Method for measuring parameters of gas-liquid two-phase flow, measuring device, apparatus and medium

Abstract

The application relates to a gas-liquid two-phase flow parameter measurement method, a measurement device, an apparatus, a computer device, a storage medium and a computer program product. The method comprises the following steps: if a measured value of liquid phase superficial velocity is equal to a calculated value of the liquid phase superficial velocity, then according to the calculated value of the liquid phase superficial velocity, a preset void fraction, a distribution parameter and a gas phase drift velocity, a P index is obtained, a calculated value of the void fraction and a calculated value of gas-liquid two-phase flow density are obtained, the initial value of the gas-liquid two-phase flow density is corrected according to the calculated value of the gas-liquid two-phase flow density, a corrected value of the gas-liquid two-phase flow density is obtained, if the deviation rate of the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than a preset value, then according to the calculated value of the gas-liquid two-phase flow density, a measurement result of the gas-liquid two-phase flow is obtained, the calculated value and the corrected value of the gas-liquid two-phase flow density are compared, the density of the gas-liquid two-phase flow measurement is calibrated, and the measurement accuracy is improved.

Description

Technical Field

[0001] This application relates to the field of nuclear power plant safety analysis technology, and in particular to a method, measuring equipment and apparatus, computer equipment, storage medium and computer program product for measuring gas-liquid two-phase flow parameters. Background Technology

[0002] A steam generator heat transfer tube rupture (SGTR) accident in a lead-bismuth fast reactor threatens reactor safety and can lead to the release of radioactive materials. Within seconds to tens of seconds, steam bubbles migrate rapidly within the lead pool, potentially entering the reactor core and introducing positive reactivity, causing a surge in reactor power; or they may rise into the cover gas region, pressurizing the cover gas and posing a risk of reactor vessel overpressure. Therefore, it is essential to understand the general laws governing gas-liquid lead-bismuth two-phase flow and establish comprehensive numerical analysis methods.

[0003] The existing method uses the pressure difference method to calculate the cavitation fraction. This method uses the principle of frictional pressure drop and form resistance pressure drop to calculate the cavitation fraction, which has the problem of inaccurate measurement. Summary of the Invention

[0004] Therefore, it is necessary to provide a method, measuring device, apparatus, computer equipment, storage medium, and computer program product for measuring gas-liquid two-phase flow parameters that can improve the accuracy of prediction, in order to address the above-mentioned technical problems.

[0005] In a first aspect, this application provides a method for measuring parameters of a gas-liquid two-phase flow, the method comprising:

[0006] The average true velocity of the gas phase is obtained by using the conductivity probe in the gas-liquid two-phase flow measurement device, and the initial flow rate of the gas-liquid two-phase flow is obtained by using the flow unit in the measurement device.

[0007] The measured value of the apparent velocity of the liquid phase is obtained based on the average true velocity of the gas phase, the preset cavitation fraction, and the initial flow rate of the gas-liquid two-phase flow, wherein the preset cavitation fraction is obtained based on the average true velocity of the gas phase.

[0008] Based on the wall shear stress on the inner side of the straight pipe in the measuring device, the average density of the gas-liquid two-phase flow, the average true velocity of the liquid phase, and the first and second shear stress expressions, the calculated value of the apparent velocity of the liquid phase is obtained. The first shear stress expression is used to characterize the mechanical equilibrium relationship of shear stress in the axial direction, and the second shear stress expression is constructed through a hybrid long model, which is used to characterize the relationship between shear stress and the average true velocity of the liquid phase.

[0009] If the measured value of the apparent velocity of the liquid phase is equal to the calculated value of the apparent velocity of the liquid phase, then the P-index is obtained based on the calculated value of the apparent velocity of the liquid phase, the preset cavitation fraction, the distribution parameter, and the gas phase drift velocity.

[0010] Based on the P index and the preset cavitation fraction, the calculated value of the cavitation fraction and the calculated value of the gas-liquid two-phase flow density corresponding to the calculated value of the cavitation fraction are obtained.

[0011] The initial value of the gas-liquid two-phase flow density is corrected based on the calculated value of the gas-liquid two-phase flow density to obtain the corrected value of the gas-liquid two-phase flow density. If the deviation rate between the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than a preset value, then the measurement result of the gas-liquid two-phase flow is obtained based on the calculated value of the gas-liquid two-phase flow density.

[0012] In one embodiment, obtaining the P-index based on the calculated value of the liquid phase apparent velocity, the preset cavitation fraction, distribution parameters, and gas phase drift velocity includes:

[0013] An expression for the weighted average value of the first cavitation fraction is obtained based on the distribution parameters, the gas phase drift velocity, and the gas phase apparent velocity, wherein the gas phase apparent velocity is obtained based on the gas phase average true velocity and the initial flow rate of the gas-liquid two-phase flow.

[0014] The expression for the weighted average value of the second void fraction is obtained based on the preset void fraction and P index;

[0015] The P-index is obtained based on the expression for the weighted average of the first cavitation fraction and the expression for the weighted average of the second cavitation fraction.

[0016] In one embodiment, the method for measuring the gas-liquid two-phase flow parameters further includes:

[0017] If the deviation rate between the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is greater than or equal to a preset value, then the calculated value of the gas-liquid two-phase flow rate is corrected according to the corrected value of the gas-liquid two-phase flow density to obtain the corrected value of the gas-liquid two-phase flow rate.

[0018] A new corrected value for the density of the gas-liquid two-phase flow is obtained based on the flow rate correction value of the gas-liquid two-phase flow.

[0019] If the deviation rate between the new corrected value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than a preset value, then the measurement result of the gas-liquid two-phase flow is obtained based on the new corrected value of the gas-liquid two-phase flow density.

[0020] In one embodiment, the step of calculating the apparent velocity of the liquid phase based on the wall shear stress inside the straight pipe of the measuring device, the average density of the gas-liquid two-phase flow, the average true velocity of the liquid phase, and the expressions for the first and second shear stresses includes:

[0021] The average density of the gas-liquid two-phase flow is obtained based on the preset cavitation fraction, empirical value of P index, and liquid phase density.

[0022] The expression for the first shear stress is obtained based on the wall shear stress and the average density of the gas-liquid two-phase flow;

[0023] The second shear stress expression is obtained based on the mixing length in the mixing length model and the average true velocity of the liquid phase.

[0024] Based on the force balance condition of the shear stress in the first and second shear stress expressions, the radial distribution of the liquid phase velocity is obtained;

[0025] The calculated value of the apparent velocity of the liquid phase is obtained by integrating the radial distribution of the liquid phase velocity along the radial direction.

[0026] In one embodiment, the method further includes: if the measured value of the apparent liquid phase velocity is not equal to the calculated value of the apparent liquid phase velocity, adjusting the value of the wall shear stress until the measured value of the apparent liquid phase velocity is equal to the calculated value of the apparent liquid phase velocity.

[0027] In one embodiment, the conductivity probe includes at least two conductivity probes, and the step of obtaining the average true velocity of the gas phase through the conductivity probes in the gas-liquid two-phase flow measurement device includes:

[0028] Obtain the potential change parameters of the at least two conductivity probes;

[0029] The average true velocity of the gas phase is obtained based on the set interval length between the at least two conductivity probes and the potential change parameters.

[0030] Secondly, this application provides a device for measuring parameters of a gas-liquid two-phase flow, the device comprising:

[0031] A Venturi tube, comprising a constriction tube, a throat, and a diffuser arranged sequentially along the flow direction of the gas-liquid two-phase flow;

[0032] A straight pipe, which is concentrically connected to the diffuser tube;

[0033] A conductivity probe, which is disposed on the inner side of the tube wall of the straight tube, is used to obtain the average true velocity of the gas phase;

[0034] A flow unit is disposed on the outer side of the tube wall of the contraction tube and the throat tube, and is used to obtain the initial flow value of the gas-liquid two-phase flow.

[0035] A processor for executing the steps of the methods described above.

[0036] Thirdly, this application provides a device for measuring parameters of a gas-liquid two-phase flow, the device comprising:

[0037] The acquisition module is used to acquire the average true velocity of the gas phase through the conductivity probe in the gas-liquid two-phase flow measurement device, and to obtain the initial flow value of the gas-liquid two-phase flow through the flow unit in the measurement device.

[0038] The first calculation module is used to obtain the measured value of the apparent velocity of the liquid phase based on the average true velocity of the gas phase, the preset cavitation fraction, and the initial value of the flow rate of the gas-liquid two-phase flow.

[0039] The second calculation module is used to obtain the calculated value of the apparent velocity of the liquid phase based on the wall shear stress on the inner side of the straight pipe in the measuring device, the average density of the gas-liquid two-phase flow, the average true velocity of the liquid phase, and the first and second shear stress expressions. The first shear stress expression is used to characterize the mechanical equilibrium relationship of the shear stress in the axial direction, and the second shear stress expression is constructed through a hybrid long model, which is used to characterize the relationship between the shear stress and the average true velocity of the liquid phase.

[0040] The first processing module is used to obtain the P-index based on the calculated value of the apparent liquid phase velocity, the preset cavitation fraction, the distribution parameter, and the gas phase drift velocity if the measured value of the apparent liquid phase velocity is equal to the calculated value of the apparent liquid phase velocity.

[0041] The third calculation module is used to obtain the calculated value of the cavitation fraction and the calculated value of the gas-liquid two-phase flow density corresponding to the calculated value of the cavitation fraction based on the P index and the preset cavitation fraction.

[0042] The second processing module is used to correct the initial value of the gas-liquid two-phase flow density based on the calculated value of the gas-liquid two-phase flow density to obtain the corrected value of the gas-liquid two-phase flow density. If the deviation rate between the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than a preset value, then the measurement result of the gas-liquid two-phase flow is obtained based on the calculated value of the gas-liquid two-phase flow density.

[0043] Fourthly, this application provides a computer device including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described above.

[0044] Fifthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0045] Sixthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the above-described method.

[0046] The aforementioned methods, equipment, devices, computer equipment, storage media, and computer program products for measuring gas-liquid two-phase flow parameters obtain the average true velocity of the gas phase directly through a conductivity probe in the gas-liquid two-phase flow measuring equipment, rather than indirectly through other measurement methods. Based on the average true velocity of the gas phase, a preset cavitation fraction, and the initial flow rate of the gas-liquid two-phase flow, the measured value of the apparent velocity of the liquid phase is obtained. Based on the wall shear stress on the inner side of the straight pipe in the measuring equipment, the average density of the gas-liquid two-phase flow, the average true velocity of the liquid phase, and the expressions for the first and second shear stresses, the calculated value of the apparent velocity of the liquid phase is obtained. If the measured value of the apparent velocity of the liquid phase is equal to the calculated value, then based on the calculated value of the apparent velocity of the liquid phase, the preset cavitation fraction, distribution parameters, and gas phase drift velocity, the P-index is obtained. Based on the P-index and the preset cavitation fraction, the calculated value of the cavitation fraction and the apparent velocity are obtained. The calculated value of the gas-liquid two-phase flow density corresponding to the calculated value of the bubble fraction is used to obtain the calculated value of the gas-liquid two-phase flow density under one cycle. The initial value of the gas-liquid two-phase flow density is corrected based on the calculated value of the gas-liquid two-phase flow density to obtain the corrected value of the gas-liquid two-phase flow density. If the deviation rate between the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than the preset value, then the measurement result of the gas-liquid two-phase flow is obtained based on the calculated value of the gas-liquid two-phase flow density. By comparing the calculated value of the gas-liquid two-phase flow density and the corrected value, if the difference between the two is less than the preset value, it means that the calculated density of the gas-liquid two-phase flow is the true density, thus improving the accuracy of the measurement result. This method, on the one hand, directly measures the average true velocity of the gas phase in the gas-liquid two-phase flow using a conductivity probe, which improves the accuracy of the measurement compared to the indirect measurement method in the prior art. On the other hand, it compares the calculated value and the corrected value of the gas-liquid two-phase flow density. If the difference is less than the preset value, the measurement result of the gas-liquid two-phase flow is obtained based on the calculated value of the gas-liquid two-phase flow density, which further improves the measurement result of the gas-liquid two-phase flow parameters. Attached Figure Description

[0047] Figure 1 This is a diagram illustrating the application environment of a method for measuring gas-liquid two-phase flow parameters in one embodiment.

[0048] Figure 2 This is a flowchart illustrating a method for measuring parameters of a gas-liquid two-phase flow in one embodiment.

[0049] Figure 3 This is a flowchart illustrating a method for measuring gas-liquid two-phase flow parameters in another embodiment.

[0050] Figure 4 This is a schematic diagram illustrating the calculation method of the shear stress expression in one embodiment;

[0051] Figure 5 This is a schematic diagram of a conductivity probe in one embodiment;

[0052] Figure 6 This is a schematic diagram of the structure of a device for measuring gas-liquid two-phase flow parameters in one embodiment;

[0053] Figure 7 This is a schematic diagram showing the placement of the probe in one embodiment;

[0054] Figure 8 This is a flowchart illustrating a method for dynamic monitoring of gas-liquid two-phase flow in one embodiment.

[0055] Figure 9 This is a schematic diagram comparing the cavitation fraction of two-phase flow with experimental results in one embodiment;

[0056] Figure 10 This is a structural block diagram of a device for measuring parameters of a gas-liquid two-phase flow in one embodiment;

[0057] Figure 11 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0059] The method for measuring gas-liquid two-phase flow parameters provided in this application embodiment can be applied to, for example... Figure 1 The application environment shown is as follows. In this environment, the measurement terminal 102 is connected to the conductivity probe 104, and the measurement terminal 102 stores the gas-liquid two-phase flow parameter data measured from the conductivity probe 104.

[0060] The measurement terminal 102 obtains the average true velocity of the gas phase through the conductivity probe 104 in the gas-liquid two-phase flow measurement device, and obtains the initial flow rate value of the gas-liquid two-phase flow through the flow unit in the measurement device. Based on the average true velocity of the gas phase, the preset cavitation fraction, and the initial flow rate value of the gas-liquid two-phase flow, the measurement terminal 102 obtains the measured value of the apparent velocity of the liquid phase. Based on the wall shear stress on the inner side of the straight pipe in the measurement device, the average density of the gas-liquid two-phase flow, the average true velocity of the liquid phase, and the expressions for the first and second shear stresses, the measurement terminal 102 obtains the calculated value of the apparent velocity of the liquid phase. If the measured value of the apparent velocity of the liquid phase is equal to the calculated value of the apparent velocity of the liquid phase... The measurement terminal 102 calculates the apparent velocity of the liquid phase, and then obtains the P-index based on the calculated apparent velocity of the liquid phase, the preset cavitation fraction, the distribution parameters, and the gas phase drift velocity. Based on the P-index and the preset cavitation fraction, the measurement terminal 102 obtains the calculated value of the cavitation fraction and the corresponding calculated value of the gas-liquid two-phase flow density. The measurement terminal 102 corrects the initial value of the gas-liquid two-phase flow density based on the calculated value. If the deviation rate between the calculated value and the initial value of the gas-liquid two-phase flow density is less than a preset value, the measurement terminal 102 obtains the measurement result of the gas-liquid two-phase flow based on the calculated value of the gas-liquid two-phase flow density.

[0061] The measurement terminal 102 can be the controller of a gas-liquid two-phase flow measurement device or the control terminal of other measurement devices. The measurement terminal 102 has the ability to collect and analyze data, and can process the data obtained from various components of the measurement device by combining it with a preset data mapping relationship to obtain the measurement results of the gas-liquid two-phase flow. The conductivity probe 104 can be a probe built into the measurement device. The conductivity probe 104 generally extends into the pipe where the gas-liquid two-phase flow occurs for measurement. The conductivity probe 104 can measure the potential level of the substance and send the potential status signal to the measurement terminal 102 for processing.

[0062] In one embodiment, such as Figure 2 As shown, a method for measuring parameters of a gas-liquid two-phase flow is provided, and this method is applied to... Figure 1 Taking the measurement terminal in the example, the following steps are included:

[0063] S202, the average true velocity of the gas phase is obtained through the conductivity probe in the gas-liquid two-phase flow measurement device, and the initial flow rate of the gas-liquid two-phase flow is obtained through the flow unit in the measurement device.

[0064] Two-phase flow, also known as gas-liquid two-phase flow, is a type of two-phase flow in alloys. Two-phase flow refers to a flow system where any two of the three phases (solid, liquid, and gas) are combined, creating an interphase interface. It can consist of gas-liquid, liquid-solid, or solid-gas combinations and is a common fluid flow phenomenon in nature and industrial applications. Examples include liquid boiling, steam condensation, blood flow, and oil transportation—all common two-phase or multiphase flow systems.

[0065] Specifically, this embodiment uses a pipeline applied to a new type of nuclear power reactor core as an example. Two-phase flow phenomena exist in the pipelines of new nuclear power reactor cores. For example, the most typical physical phenomenon under a lead-bismuth fast reactor SGTR accident is the "gas-liquid metal two-phase flow" formed in the steam injection pool. Currently, lead-bismuth fast reactors mostly adopt a pool-type structure design, that is, the reactor core, steam generator, and internal components are immersed in a container filled with liquid metal. Although this improves the compactness and economy of the reactor, it also brings new safety challenges. The heat transfer tubes of the steam generator are subject to thermal stress and mechanical stress caused by the temperature and pressure difference between the two sides of the tube wall (liquid metal and water), as well as corrosion from the lead-bismuth alloy (LBE). This can easily lead to a heat transfer tube rupture (SGTR) accident, threatening reactor safety and causing radioactive material leakage. Under normal circumstances, the pipeline is filled with liquid metal (lead-bismuth alloy). When an SGTR accident occurs, steam bubbles in the heat transfer tubes and the existing liquid metal form a gas-liquid metal two-phase flow.

[0066] Among these, the steam generator heat transfer tube rupture (SGTR) accident in a lead-bismuth fast reactor threatens reactor safety and can lead to the release of radioactive materials. Within seconds to tens of seconds, steam bubbles migrate and flow rapidly within the lead pool, potentially entering the reactor core, introducing positive reactivity, and causing a surge in reactor power. Alternatively, they may rise into the cover gas region, pressurizing the cover gas and posing a risk of reactor vessel overpressure. Therefore, it is crucial to understand the general laws governing gas-liquid lead-bismuth two-phase flow and establish comprehensive measurement methods.

[0067] When measuring gas-liquid metal two-phase flow, an important parameter is the actual velocity of the gas phase.

[0068] Among these challenges, the opacity of lead-bismuth alloy (LBE) makes visualization difficult. Currently, neutron imaging is one method for observing local flow fields; however, this method requires sophisticated neutron source and irradiation shielding, and it limits the design of the flow channel test section to a two-dimensional flat box structure to allow the neutron beam to pass through, making it difficult to investigate the influence of the flow channel structure on the two-phase flow. Therefore, existing research still has certain limitations.

[0069] Among them, the average true velocity U of the gas phase is obtained by using the conductivity probe in the gas-liquid two-phase flow measurement device. GSpecifically, a conductivity probe is typically inserted into the pipe wall to measure the gas-liquid two-phase flow. The movement speed of the gas phase can be determined based on the potential of the conductivity probe. It should be noted that the potential of the gas phase is high and the potential of the liquid phase is low.

[0070] The initial flow rate of the gas-liquid two-phase flow can be obtained through the flow unit in the measuring device. The flow unit generally includes at least two probes for pressure detection. The pressure of the two-phase flow at at least two points in the variable cross-section pipe is obtained through the pressure detection probes. Then, the average flow rate V (volume flow rate information) of the two-phase flow is given according to the flow continuity equation and Bernoulli equation, which is the initial flow rate of the gas-liquid two-phase flow.

[0071] S204. Based on the average true velocity of the gas phase, the preset cavitation fraction, and the initial flow rate of the gas-liquid two-phase flow, the measured value of the apparent velocity of the liquid phase is obtained.

[0072] Among them, the cavitation fraction α refers to the cross-sectional gas holdup, which is the ratio of the cross-sectional area occupied by the gas phase to the total cross-sectional area at a certain interface in a two-phase flow. The cross-sectional gas holdup is directly related to the relative velocity between the two phases and has the characteristics of thermodynamic imbalance. It is difficult to use the continuity equation and thermodynamic equilibrium equation to calculate the cross-sectional gas holdup to represent the volume fraction of the gas phase existing in the flow channel.

[0073] The preset void fraction can refer to the center gas content α of the cross section. C The gas holdup at the center of the cross section is derived from the average true gas phase velocity. Specifically, the expression for the gas holdup at the center of the cross section is as follows:

[0074]

[0075] in, <j G + > is the dimensionless cross-sectional average apparent gas phase velocity, i.e.:

[0076]

[0077] Where σ and g represent the surface tension coefficient and gravitational acceleration, respectively. ρ L and ρ G These are the liquid and gas phase densities under the current pressure and temperature conditions, respectively. <j G > is the apparent velocity of the gas phase, which can be derived from the average true velocity of the gas phase, U. G It is derived.

[0078] Among them, the measured value of the apparent velocity of the liquid phase <j L1Apparent velocity is used to measure the flow velocity of the liquid phase in a two-phase or multiphase flow. Specifically, it is the velocity at which a virtual (artificial) flow, or the velocity at which a single fluid flows through a region, is assumed. Other phases, particles, or porous media are not considered.

[0079] Among them, the average true velocity of the gas phase U can be used as a basis. G The preset void fraction α and the initial flow rate V of the gas-liquid two-phase flow are obtained, and the measured value of the apparent velocity of the liquid phase is obtained. <j L1 Specifically, the pre-defined void fraction α here can be represented by the center gas content α of the cross section. C Let U represent the gas content at the center of the cross-section, as measured by the average true gas velocity U in the gas phase using a conductivity probe. G Then, based on the average true velocity U in the gas phase G The expression for the gas holdup at the center of the cross section is used to obtain the gas holdup α at the center of the cross section. C .

[0080] After obtaining the preset void fraction α, based on the expression for gas phase velocity, the preset void fraction α, and the average true gas phase velocity U... G The gas phase velocity j is obtained. G And the apparent velocity of the gas phase corresponding to the gas phase velocity. <j G > The expression for the gas phase velocity is: j G =U G α.

[0081] Furthermore, the total volumetric flow density of the two phases is obtained based on the initial flow rate V of the gas-liquid two-phase flow and the cross-sectional area A of the straight pipe containing the two-phase flow. <j>The total two-phase volumetric flow density is used to represent the sum of the apparent velocities of the two-phase flows. Specifically, the total two-phase volumetric flow density... <j>The expression is: <j>=V / A.

[0082] The expression for the total volumetric flow density of the two-phase flow is: <j>= <j L >+ <j G >

[0083] Based on the average true velocity of the gas phase, the preset cavitation fraction, and the initial flow rates of the gas-liquid two-phase flow, the measured value of the apparent velocity of the liquid phase is obtained. <j L1 >

[0084] S206. Based on the wall shear stress on the inner side of the straight pipe in the measuring device, the average density of the gas-liquid two-phase flow, the average true velocity of the liquid phase, and the first and second shear stress expressions, the calculated value of the apparent velocity of the liquid phase is obtained. The first shear stress expression is used to characterize the mechanical equilibrium relationship of the shear stress in the axial direction, and the second shear stress expression is constructed through a hybrid long model, which is used to characterize the relationship between the shear stress and the average true velocity of the liquid phase.

[0085] Among them, the wall shear stress τ W This refers to the wall shear stress of a straight pipe section in a gas-liquid two-phase flow measurement device.

[0086] Specifically, the first shear stress expression describes the mechanical equilibrium relationship of shear stress in the axial direction. The left side of the first shear stress expression is the axial shear stress τ(r), and the right side is the wall shear stress τ. W The gas-liquid two-phase flow density ρ0, wherein the gas-liquid two-phase flow density ρ0 includes the average density of the two-phase flow within the cylindrical flow channel with radius R and radius r (the two-phase flow density corresponding to radius R is ρ0(R) and the two-phase flow density corresponding to radius r is ρ0(r)).

[0087] The expression for the second shear stress is constructed using the Prandtl hybrid long model. The left side of the expression represents the shear stress τ(r), and the right side represents the average true velocity U in the liquid phase. L .

[0088] Specifically, the absolute values ​​of the first and second shear stress expressions can be made equal, assuming the wall shear stress τ W The initial value of dU can be directly obtained from the location of the stagnation point on the radial velocity curve. L / dr is the discrete value in each radial coordinate, and then U L Given the boundary condition (r=R)=0, the radial velocity distribution U of the liquid phase can be obtained by numerical integration using the first-order Taylor formula. L (r), and further, the radial distribution of the liquid phase velocity U L (r) Integrating radially yields the calculated value of the apparent velocity of the liquid phase. <j L2 >

[0089] S208, if the measured value of the apparent velocity of the liquid phase is equal to the calculated value of the apparent velocity of the liquid phase, then the P index is obtained based on the calculated value of the apparent velocity of the liquid phase, the preset cavitation fraction, the distribution parameters, and the gas phase drift velocity.

[0090] Among them, if the measured value of the apparent velocity of the liquid phase <j L1 >Equal to the calculated value of the apparent velocity in the liquid phase <j L2 >, then based on the calculated value of the apparent velocity of the liquid phase <j L2 >Preset cavitation fraction α, distribution parameter C0, gas phase drift velocity U GM The P-index is obtained.

[0091] Wherein, the distribution parameter C0 refers to the distribution of the void fraction, and the expression for the distribution parameter C0 is as follows:

[0092]

[0093] Wherein, the distribution parameter C0 is a parameter defined by the calculation module, and <αj> refers to the weighted average of the product of the void fraction and the two-phase volumetric density. <αj> is based on the preset void fraction α and the total two-phase volumetric density. <j>Calculated.

[0094] In addition, regarding the gas phase drift velocity U GM The drift flow correlation was also defined:

[0095]

[0096] The above formula can be written in the following form:

[0097]

[0098] The weighted average value <α1> of the first cavitation fraction can be obtained through the drift correlation. Specifically, the formula for calculating the weighted average value <α1> of the first cavitation fraction includes: distribution parameter C0, apparent velocity of the gas phase, etc. <j G Two-phase total volumetric flow density <j>and gas phase drift velocity

[0099] The weighted average value <α2> of the second void fraction can be obtained by considering the gas content at the cross-section. Specifically, the formula for calculating the weighted average value <α2> of the second void fraction includes: a preset void fraction α (which can be the gas content α at the center of the cross-section). C ) and the index P, which is not an empirical value but an unknown quantity.

[0100] Based on the above two formulas for calculating cavitation shares, the value of the index P can be obtained by setting the average weight of the first cavitation share <α1> and the average weight of the second cavitation share <α2> to be equal.

[0101] S210, based on the P index and the preset cavitation fraction, obtain the calculated value of the cavitation fraction and the calculated value of the gas-liquid two-phase flow density corresponding to the calculated value of the cavitation fraction.

[0102] Based on the P-index and the preset cavitation fraction α, the calculated value of the cavitation fraction <α> and the calculated value of the gas-liquid two-phase flow density corresponding to the calculated cavitation fraction are obtained.

[0103] Among them, the P index and the preset void fraction α (gas content at the center of the cross section α) can be used as the basis. C The expression for the second void fraction is used to obtain the calculated value of the void fraction <α>. Specifically, the expression for the second void fraction is as follows:

[0104]

[0105] After obtaining the calculated value of the cavitation fraction <α> (i.e., <α2>), the calculated value of the gas-liquid two-phase flow density ρ(r) can be obtained based on the P-index, the preset cavitation fraction α, and the liquid phase density. Specifically, the expression for the calculated value of the gas-liquid two-phase flow density is as follows:

[0106]

[0107] Where ρ(r) is the calculated value of the gas-liquid two-phase flow density, ρ L The liquid phase density is determined based on the temperature and pressure measured by the current sensor.

[0108] S212, the initial value of the gas-liquid two-phase flow density is corrected based on the calculated value of the gas-liquid two-phase flow density to obtain the corrected value of the gas-liquid two-phase flow density. If the deviation rate between the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than the preset value, the measurement result of the gas-liquid two-phase flow is obtained based on the calculated value of the gas-liquid two-phase flow density.

[0109] The initial value of the gas-liquid two-phase flow density can be the liquid phase density. Taking the pipeline of a new type of nuclear power reactor core as an example, if there is no gas leakage in the pipeline, the material in the pipeline can be liquid lead-bismuth alloy. In this case, the initial value of the gas-liquid two-phase flow density is the density of the lead-bismuth alloy. Specifically, the current density value of the lead-bismuth alloy can be calculated by obtaining the temperature and pressure inside the pipeline.

[0110] Since the initial value ρ0 of the gas-liquid two-phase flow density is an assumed value and differs significantly from the actual density, a calculation is first performed on the initial value ρ0 to obtain the calculated value ρ1 of the gas-liquid two-phase flow density and the calculated value V1 of the gas-liquid two-phase flow rate. Then, based on the calculated values ​​ρ1 and V1, iterative calculations are performed to obtain the corrected values ​​ρ2 and V2 of the gas-liquid two-phase flow density and flow rate. Finally, the deviation rate between the calculated values ​​ρ1 and ρ2 is compared with a preset value. If the deviation rate between the calculated values ​​ρ1 and ρ2 is less than the preset value, the measurement result of the gas-liquid two-phase flow is obtained based on the calculated values ​​of the gas-liquid two-phase flow density.

[0111] Specifically, based on the calculated value ρ1 of the gas-liquid two-phase flow density, the calculated flow rate V1 of the gas-liquid two-phase flow is obtained, including: based on the calculated value ρ1 of the gas-liquid two-phase flow density and the pipe area ratio. The flow rate V1 of the gas-liquid two-phase flow is obtained by using the pipeline pressure difference p1-p2, the target cross-sectional area S2, and the cross-sectional area S1 at the throat of the measuring equipment.

[0112] The expression for the calculated flow rate V1 of the gas-liquid two-phase flow is as follows:

[0113]

[0114] The corrected value ρ2 of the gas-liquid two-phase flow density is calculated based on the calculated flow rate V1 of the gas-liquid two-phase flow. After obtaining the corrected value ρ2 of the gas-liquid two-phase flow density, the deviation rate between the calculated value ρ1 and the corrected value ρ2 of the gas-liquid two-phase flow density is compared with a preset value. If the deviation rate is less than the preset value, the measurement result of the gas-liquid two-phase flow is obtained based on the calculated value ρ1 of the gas-liquid two-phase flow density.

[0115] Furthermore, if the deviation rate between the calculated value ρ1 of the gas-liquid two-phase flow density and the corrected value ρ2 of the gas-liquid two-phase flow density is greater than or equal to a preset value, then the calculated value V1 of the gas-liquid two-phase flow is corrected according to the corrected value ρ2 of the gas-liquid two-phase flow density to obtain the flow rate correction value V2 of the gas-liquid two-phase flow. Then, a new corrected value ρ3 of the gas-liquid two-phase flow density is calculated based on the flow rate correction value V2. If the deviation rate between the corrected value ρ2 of the gas-liquid two-phase flow density and the new corrected value ρ3 of the gas-liquid two-phase flow density is less than a preset value, then the measurement result of the gas-liquid two-phase flow can be calculated based on any one of the gas-liquid two-phase flow densities; otherwise, the above steps are repeated until two consecutive gas-liquid two-phase flow densities ρ1 and ρ2 are obtained. n and ρ n+1 The deviation rate between them is less than the preset value, at which point ρ n and ρ n+1 The values ​​can all be considered as the true density. The preset value can be one ten-thousandth. The various measurement results can be calculated based on one of the gas-liquid two-phase flow densities.

[0116] Specifically, the correction value ρ2 for the gas-liquid two-phase flow density is calculated based on the flow rate V1 of the gas-liquid two-phase flow, including:

[0117] Recalculate the total volumetric flow density of the two phases based on the calculated flow rate V1 of the gas-liquid two-phase flow. <j>Then, based on the total volumetric flow density of the two phases <j>Gas-phase average true velocity U G The corrected value ρ2 for the gas-liquid two-phase flow density is obtained.

[0118] The measurement results can include cavitation fraction, distribution parameters, average true velocity of the gas phase, average true velocity of the liquid phase, gas phase drift velocity, bubble frequency, etc. Specifically, when the value of the gas-liquid two-phase flow density meets the preset requirements, the cavitation fraction, distribution parameters, average true velocity of the liquid phase, and gas phase drift velocity are solved based on the current gas-liquid two-phase flow density. The average true velocity of the gas phase and the bubble frequency can be directly measured by a conductivity probe.

[0119] Specifically, the current flow rate V of the gas-liquid two-phase flow is calculated based on the current gas-liquid two-phase flow density ρ. The total volumetric flow density of the two phases is then calculated based on the current flow rate V and the cross-sectional area A of the straight pipe section. <j>.

[0120] Based on the total volumetric flow density of the two phases <j>Pre-measured gas-phase average true velocity U G The void fraction α is obtained based on the void fraction α and the total volumetric flow density of the two phases. <j>The distribution parameter C0 is obtained.

[0121] Based on the void fraction α, the average true gas velocity U G The average true velocity U in the liquid phase was obtained. L .

[0122] Based on the pre-measured average true velocity of the gas phase U G and total volumetric flow density of the two phases <j>The gas phase drift velocity U is obtained. GM =U G -j.

[0123] In this embodiment, the average true velocity of the gas phase is obtained directly through a conductivity probe in a gas-liquid two-phase flow measurement device, rather than indirectly through other measurement methods. Based on the average true velocity of the gas phase, a preset cavitation fraction, and the initial flow rate of the gas-liquid two-phase flow, the measured value of the apparent velocity of the liquid phase is obtained. Based on the wall shear stress on the inner side of the straight pipe in the measurement device, the average density of the gas-liquid two-phase flow, the average true velocity of the liquid phase, and the expressions for the first and second shear stresses, the calculated value of the apparent velocity of the liquid phase is obtained. If the measured value of the apparent velocity of the liquid phase is equal to the calculated value, then based on the calculated value of the apparent velocity of the liquid phase, the preset cavitation fraction, distribution parameters, and gas phase drift velocity, the P-index is obtained. Based on the P-index and the preset cavitation fraction, the calculated value of the cavitation fraction and the apparent velocity are obtained. The calculated value of the gas-liquid two-phase flow density corresponding to the calculated value of the bubble fraction is used to obtain the calculated value of the gas-liquid two-phase flow density under one cycle. The initial value of the gas-liquid two-phase flow density is corrected based on the calculated value of the gas-liquid two-phase flow density to obtain the corrected value of the gas-liquid two-phase flow density. If the deviation rate between the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than the preset value, then the measurement result of the gas-liquid two-phase flow is obtained based on the calculated value of the gas-liquid two-phase flow density. By comparing the calculated value of the gas-liquid two-phase flow density and the corrected value, if the difference between the two is less than the preset value, it means that the calculated density of the gas-liquid two-phase flow is the true density, thus improving the accuracy of the measurement result. This method, on the one hand, directly measures the average true velocity of the gas phase in the gas-liquid two-phase flow using a conductivity probe, which improves the accuracy of the measurement compared to the indirect measurement method in the prior art. On the other hand, it compares the calculated value and the corrected value of the gas-liquid two-phase flow density. If the difference is less than the preset value, the measurement result of the gas-liquid two-phase flow is obtained based on the calculated value of the gas-liquid two-phase flow density, which further improves the measurement result of the gas-liquid two-phase flow parameters.

[0124] In one embodiment, the P-index is obtained based on the calculated value of the liquid phase apparent velocity, a preset cavitation fraction, distribution parameters, and gas phase drift velocity. This includes: obtaining an expression for the weighted average value of the first cavitation fraction based on the distribution parameters, gas phase drift velocity, and gas phase apparent velocity, wherein the gas phase apparent velocity is obtained based on the average true gas phase velocity and the initial flow rate of the gas-liquid two-phase flow; obtaining an expression for the weighted average value of the second cavitation fraction based on the preset cavitation fraction and the P-index; and obtaining the P-index based on the expression for the weighted average value of the first cavitation fraction and the expression for the weighted average value of the second cavitation fraction.

[0125] It should be noted that the average values ​​of various parameters must be defined beforehand. The definition methods include: cross-sectional average values. <f>and weighted average

[0126] The cross-sectional average value refers to the average value of the parameters at the target cross-section. The expression for the cross-sectional average value is:

[0127]

[0128] Where A is the cross-sectional area of ​​the straight pipe.

[0129] Weighted average The expression is:

[0130]

[0131] Where A can be the cross-section of a straight pipe, and α is the preset cavitation fraction.

[0132] The expression for the weighted average value <α1> of the first void fraction is:

[0133]

[0134] Where C0 is the distribution parameter, <j G > represents the apparent velocity in the gas phase. <j>The total volumetric flow density of the two phases. Let U be the gas phase drift velocity, where U can be determined based on the average true gas phase velocity. G The apparent velocity of the gas phase is obtained from the initial flow rate V of the gas-liquid two-phase flow. <k G > The distribution parameter C0 refers to the distribution of the void fraction, and its expression is as follows:

[0135]

[0136] Specifically, the expression for the weighted average value <α> of the first cavitation fraction can be derived from the gas phase drift velocity U. GM The drift correlation is derived.

[0137] Among them, for the gas phase drift velocity U GM Define the drift flow correlation:

[0138]

[0139] The above formula can be written in the following form:

[0140]

[0141] The weighted average value <α> of the first cavitation fraction can be obtained through the drift correlation.

[0142] The weighted average expression for the second void fraction is:

[0143]

[0144] The expression for the weighted average value <α> of the second void fraction can be derived from the formula for the gas content of the target section. Specifically, the formula for the gas content of the target section is:

[0145]

[0146] Where α(r) represents the gas content distribution along the radial section of the pipe, α C Let α(r) represent the gas content at the center of the cross-section (the preset cavitation fraction), r represent the diameter of the measurement position from the center point, R represent the straight pipe radius, and P be the bankoff exponent. The weighted average expression for the second cavitation fraction can be obtained by integrating α(r) radially.

[0147] The P-index is obtained by using the expressions for the weighted average of the first cavitation share and the weighted average of the second cavitation share, including: setting the weighted average of the first cavitation share and the weighted average of the second cavitation share equal to obtain the value of the P-index.

[0148] In this embodiment, by using two methods to calculate the cavitation fraction—drift correlation and gas content distribution—an accurate P-index is obtained, thereby improving the accuracy of subsequent measurement results.

[0149] In one embodiment, such as Figure 3 As shown, the methods for measuring gas-liquid two-phase flow parameters also include:

[0150] S302, determine whether the deviation rate between the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is greater than or equal to the preset value. If yes, execute S304; otherwise, execute S314.

[0151] The deviation rate refers to the difference between the calculated value and the corrected value divided by the calculated value (or the corrected value). The preset value of the deviation rate can be set to one ten-thousandth.

[0152] S304, the calculated flow rate of the gas-liquid two-phase flow is corrected based on the correction value of the gas-liquid two-phase flow density to obtain the corrected flow rate value of the gas-liquid two-phase flow.

[0153] S306, based on the flow rate correction value of the gas-liquid two-phase flow, obtain a new correction value for the gas-liquid two-phase flow density.

[0154] S308, determine whether the deviation rate between the new correction value of the gas-liquid two-phase flow density and the correction value of the gas-liquid two-phase flow density is less than the preset value. If yes, execute S310; otherwise, execute S312.

[0155] S310, based on the new correction value of the gas-liquid two-phase flow density or the correction value of the gas-liquid two-phase flow density, the measurement result of the gas-liquid two-phase flow is obtained.

[0156] S312, continue to correct until the density deviation rate calculated after two consecutive corrections is less than the preset value. Then, select one of the gas-liquid two-phase flow density values ​​obtained after these two corrections and calculate the measurement result of the gas-liquid two-phase flow.

[0157] It should be noted that the deviation of the density values ​​of the gas-liquid two-phase flow after two consecutive correction calculations can be compared. If the deviation is less than the preset value, the density values ​​of the gas-liquid two-phase flow are considered to be true and reliable. One of them can be randomly selected as the value of the gas-liquid two-phase flow density. The measurement result of the gas-liquid two-phase flow can be obtained based on the selected value of the gas-liquid two-phase flow density.

[0158] The measurement results include: gas-phase average true velocity U G Bubble frequency, void fraction α, distribution parameter C0, and average true liquid velocity U L Parameters

[0159] In this case, the average true gas velocity U can be directly measured. G Bubble frequency can be measured using a conductivity probe, and it characterizes the number of bubbles in a two-phase flow over a period of time.

[0160] In calculating the gas-liquid two-phase flow density ρ, the cavitation fraction α, the distribution parameter C0, and the average true liquid velocity U can be obtained. L Parameters such as these.

[0161] S314. Based on the correction value or the calculated value of the gas-liquid two-phase flow density, the measurement result of the gas-liquid two-phase flow is obtained.

[0162] In this embodiment, if the density deviation rate after two consecutive corrected calculations is less than a preset value, one of the two calculated gas-liquid two-phase flow densities is randomly selected as the new corrected value for the gas-liquid two-phase flow density; otherwise, either the new corrected value or the corrected value of the gas-liquid two-phase flow density is selected as the new corrected value for the gas-liquid two-phase flow density. The flow rate of the gas-liquid two-phase flow is corrected by the gas-liquid two-phase flow density, thereby making the measured gas-liquid two-phase density continuously approach the true value and improving the accuracy of the measurement results.

[0163] In one embodiment, such as Figure 4 The diagram illustrates the calculation method for the shear stress expression. Based on the first shear stress expression (wall shear stress, average density of the gas-liquid two-phase flow, wall shear stress and gas-liquid two-phase flow density), the average true velocity of the liquid phase, and the second shear stress expression (mixing long model and average true velocity of the liquid phase), the calculated value of the apparent velocity of the liquid phase is obtained, including:

[0164] S402, based on the preset cavitation fraction, empirical value of P index, and liquid phase density, obtains the average density of the gas-liquid two-phase flow.

[0165] Among them, according to the preset void fraction α C Liquid phase density ρ L The liquid phase density is calculated by measuring the current temperature and pressure of the two-phase flow using sensors. The empirical value of the P-index can be between 0 and 7; specifically, an empirical value of 7 is possible.

[0166] Specifically, the average density of a gas-liquid two-phase flow can be the difference between the average density within the entire flow channel radius R and the average density within a flow channel of radius r, i.e., ρ0(R) - ρ0(r0). The expression for the average density of a gas-liquid two-phase flow is as follows:

[0167]

[0168] S404, based on the wall shear stress and the average density of the gas-liquid two-phase flow, the expression for the first shear stress is obtained.

[0169] The axial shear stress τ(r) has the following mechanical equilibrium equation, which is the expression for the first shear stress:

[0170]

[0171] S406, the second shear stress expression is obtained based on the mixing length and the average true velocity of the liquid phase in the mixing length model.

[0172] The second shear stress is expressed by the Prandtl mixed-length model:

[0173]

[0174] Where l is the mixing length, U L This represents the average true velocity in the liquid phase.

[0175] The formula for calculating the mixed length l is as follows:

[0176]

[0177] In the above equation, N is the turbulence constant, and y + It is a dimensionless distance.

[0178] S408, based on the force balance condition of the shear stress in the first and second shear stress expressions, obtains the radial distribution of the liquid phase velocity.

[0179] Considering the direction of shear stress, the force balance condition of shear stress in the first and second shear stress expressions yields the radial distribution of liquid phase velocity.

[0180]

[0181] Assuming wall shear stress τ W The initial value of dU can be directly obtained from the location of the stagnation point on the radial velocity curve. L / dr is the discrete value in each radial coordinate, and then U L Given the boundary condition (r=R)=0, the radial velocity distribution U of the liquid phase can be obtained by numerical integration using the first-order Taylor formula. L (r).

[0182] S410, the apparent velocity of the liquid phase is calculated by integrating radially along the radial distribution of the liquid phase velocity.

[0183] Furthermore, regarding the liquid phase flow rate U L (r) The average velocity of the liquid phase cross section can be obtained by radial trapezoidal integration, that is, the calculated value of the apparent velocity of the liquid phase.

[0184]

[0185] In this embodiment, two shear stress calculation methods are used. The liquid phase velocity distribution is solved by the shear stress equilibrium condition, and then the apparent velocity of the liquid phase is calculated based on the radial distribution of the liquid phase velocity, which improves the accuracy of subsequent measurement results.

[0186] In one embodiment, the method for measuring the parameters of the gas-liquid two-phase flow further includes: if the measured value of the apparent velocity of the liquid phase is not equal to the calculated value of the apparent velocity of the liquid phase, adjusting the value of the wall shear stress until the measured value of the apparent velocity of the liquid phase is equal to the calculated value of the apparent velocity of the liquid phase.

[0187] One approach is to set the difference between the calculated and measured values ​​of the apparent liquid phase velocity as the objective function, for example, by using the Newton-Raphson method to find the roots of the objective function. After multiple updates and iterative calculations of the wall shear stress, the two values ​​are repeated until they are equal, meaning the measured value of the apparent liquid phase velocity equals the calculated value.

[0188] The simulation can be used to measure the wall shear stress. The simulated value of the wall shear stress is continuously adjusted until, after multiple updates and iterations of the wall shear stress, the difference between the calculated and measured values ​​of the liquid phase apparent velocity is zero, and then the current simulated value of the wall shear stress is output.

[0189] In this embodiment, by iteratively calculating the objective function corresponding to the calculated and measured values ​​of the liquid phase apparent velocity, and updating the wall shear stress multiple times until the measured value of the liquid phase apparent velocity equals the calculated value, the calculated value of the liquid phase apparent velocity can be obtained quickly and accurately, which can improve the accuracy of subsequent measurement results.

[0190] In one embodiment, the conductivity probe includes at least two conductivity probes. Obtaining the average true velocity of the gas phase through the conductivity probes in the gas-liquid two-phase flow measurement device includes: obtaining the potential change parameters of at least two conductivity probes, and obtaining the average true velocity of the gas phase based on the setting interval length between at least two conductivity probes and the potential change parameters.

[0191] Among them, such as Figure 5 The schematic diagram of the conductivity probe shown includes: a first electrode, a second electrode, and an insulating material. Taking a two-phase flow of lead-bismuth alloy mixed bubbles as an example: When the bubbles migrate with the molten lead-bismuth and pass through the conductivity probe, the circuit between the first and second electrodes of the conductivity probe is broken, and the potential of the conductivity probe is high. When the bubbles leave the conductivity probe, the molten lead-bismuth alloy causes the circuit between the first and second electrodes of the conductivity probe to become conductive, and the potential of the conductivity probe is low.

[0192] Specifically, taking a scenario with three conductivity probes as an example: A first conductivity probe, a second conductivity probe, and a third conductivity probe are positioned in the direction of the two-phase flow. When a bubble migrates with the molten lead-bismuth, it passes through the first conductivity probe, the second conductivity probe, and the third conductivity probe in sequence. Before the leading edge of the bubble touches the first conductivity probe, the signals of the first, second, and third probes are sequentially "low level - low level - low level". The instant the bubble contacts the first conductivity probe, the signal of the third probe changes sequentially from "high level - low level - low level," and this moment is recorded as t1. The instant the bubble contacts the second conductivity probe, the signal of the third probe changes to "high level - low level," and this moment is recorded as t2. The instant the bubble contacts the first conductivity probe, the signal of the third probe changes to "high level," and this moment is recorded as t3. When the bubble leaves, the first conductivity probe returns to a low level first, and this moment is recorded as t1'. The instant the bubble leaves the second conductivity probe, the signal of the second probe changes to a low level, and this moment is recorded as t2'. The instant the bubble leaves the third conductivity probe, the signal of the third probe returns to a low level, and this moment is recorded as t3'. The true velocity of the first gas phase is obtained based on the times t1, t2, t3, and the interval Δ between the conductivity probes. The true velocity of the second gas phase is obtained based on the times t1', t2', t3', and the interval Δ between the conductivity probes. The average true velocity of the gas phase is then obtained based on the true velocities of the first and second gas phases.

[0193] In this embodiment, the average true gas phase velocity is directly calculated based on the potential change parameters of the conductivity probes and the interval length of each conductivity probe, which improves the accuracy of the measurement results.

[0194] In one embodiment, obtaining the measurement result of the gas-liquid two-phase flow based on the new correction value of the gas-liquid two-phase flow density includes: obtaining the target value of the flow rate of the gas-liquid two-phase flow based on the new correction value of the gas-liquid two-phase flow density; calculating the P index based on the target value of the flow rate of the gas-liquid two-phase flow and the average true velocity of the gas phase; and obtaining the measurement result of the cavitation fraction in the measurement result based on the P index and a preset cavitation fraction.

[0195] One approach is to correct the flow rate of the gas-liquid two-phase flow based on the new correction value to obtain the target value of the gas-liquid two-phase flow flow. Alternatively, one can deduce the previous gas-liquid two-phase flow flow value by looking back at the new correction value.

[0196] After obtaining the target flow rate value of the gas-liquid two-phase flow, the total volumetric flow density j of the two phases is calculated based on the target flow rate value V, where j = V / A. The average true velocity U of the gas phase is then obtained. G The apparent velocity of the gas phase was calculated. <j G >=U G / j.

[0197] Among them, based on the apparent velocity of the gas phase <j G >Obtain the dimensionless cross-sectional average apparent gas phase velocity <j G + Specifically, the dimensionless cross-sectional average apparent gas phase velocity. <j G + The expression is:

[0198]

[0199] Where σ and g represent the surface tension coefficient and gravitational acceleration, respectively. ρ L and ρ G These are the liquid and gas phase densities under the current pressure and temperature conditions, respectively. <j G > represents the apparent velocity in the gas phase.

[0200] Based on the dimensionless cross-sectional average apparent velocity of the gas phase <j G + >Obtain the gas content α at the center of the cross section C (Preset cavitation ratio)

[0201]

[0202] The value of the P-index is obtained by using the expressions for the two cavitation fractions.

[0203] The weighted average value of the void fraction is obtained based on the P-index and the preset void fraction. The expression for the weighted average value of the void fraction <α> is as follows:

[0204]

[0205] The weighted average value of the cavitation fraction is the value of the cavitation fraction in the measurement results.

[0206] It should be noted that after calculating the cavitation fraction, the distribution parameter C0 and the average true velocity of the liquid phase U can be obtained from this cavitation fraction. L Gas phase drift velocity U GM wait.

[0207] Among them, the average true velocity U of the liquid phase is calculated. L and gas phase drift velocity U GM The methods include:

[0208] Based on the cavitation fraction α and the obtained average true gas velocity U G =j G / α yields the apparent velocity j in the gas phase G .

[0209] Based on the total volumetric density j of the two-phase flow and the apparent velocity j of the gas phase G Obtain the apparent velocity j of the liquid phase L and the average true velocity U in the liquid phase L =j L / (1-α).

[0210] The gas phase drift velocity U can also be obtained from this. GM =U G -j, the liquid phase drift velocity is U LM =U L -j, it should be noted that the actual gas-liquid relative velocity U GL =U G -U L For bubbly flow with α < 0.25, U GM =U GL (1-α).

[0211] Methods for calculating the distributed parameter C0 include: considering the direction of shear stress, the first shear stress expression and the second shear stress expression have the following force equilibrium conditions.

[0212]

[0213] The above equation is dimensionless, where D = 2R.

[0214] Then there is,

[0215]

[0216] in,

[0217]

[0218]

[0219]

[0220]

[0221] Ga represents the Galileo number. The expression for the average velocity across the liquid phase cross section (apparent velocity of the liquid phase) is:

[0222]

[0223] At this point, the expression for the average velocity across the liquid phase cross section (apparent velocity of the liquid phase) is written as:

[0224]

[0225] Easy to obtain

[0226]

[0227] as well as,

[0228]

[0229] The expression for the distribution parameter C0 is:

[0230]

[0231] Dimensionlessize the expression:

[0232]

[0233] Wherein, the Froude number Fr is,

[0234]

[0235] Among them, the void fraction α and the cross-sectional gas content α were obtained. C P-index, liquid-phase average true velocity U L Then, the C0 value of the distribution parameter can be calculated.

[0236] In this embodiment, the measurement results of the gas-liquid two-phase flow are obtained by using a new corrected value of the gas-liquid two-phase flow density. A method for measuring the parameters of the two-phase flow is established. Based on the measured parameters, the flow state of the two-phase flow can be monitored, and the flow state of the two-phase flow can be predicted within a certain time range, thereby improving the monitoring effect of the two-phase flow.

[0237] In one embodiment, such as Figure 6 The diagram shows the structure of the device for measuring gas-liquid two-phase flow parameters.

[0238] The system includes: a Venturi tube comprising a contraction tube, a throat, and a diffuser arranged sequentially along the gas-liquid two-phase flow direction; a straight tube concentrically connected to the diffuser; a conductivity probe disposed on the inner wall of the straight tube for acquiring the average true gas phase velocity; a flow rate unit disposed on the outer wall of the contraction tube and the throat for acquiring the initial flow rate value of the gas-liquid two-phase flow; and a processor for executing the steps of the above method.

[0239] The Venturi tube includes a contraction tube, a throat, and a diffuser. The contraction tube has a frustum-shaped cross-section, the throat, also known as the throat passage, is a short straight tube, and the diffuser has a frustum-shaped cross-section. Temperature and pressure measuring units can be installed in different sections of the Venturi tube to calculate the estimated density ρ of the substance inside the Venturi tube.

[0240] The straight pipe is communicatively connected to the diffuser end of the Venturi tube, and the diameter of the straight pipe is equal to the maximum diameter of the diffuser. The flow unit is located inside the walls of the contraction and throat pipes and is used to measure the flow rate V of the gas-liquid two-phase flow within the Venturi tube.

[0241] The probe can include electrodes and insulating material, and is used to determine whether the substance at the measurement location is a gas or a liquid. If it is a gas, the probe has a high potential, and if it is a liquid, the probe has a low potential.

[0242] In this embodiment, a probe is set to determine the type of substance in the gas-liquid two-phase flow, and then the average true velocity of the gas phase is calculated. The gas phase density and liquid phase density of the gas-liquid two-phase flow are measured by the temperature and pressure unit, and the flow rate V of the gas-liquid two-phase flow in the venturi tube is measured by the flow unit. The measurement of various parameters is completed, providing a basis for the calculation of other parameters in the future.

[0243] In one embodiment, the probe includes a first probe, a second probe, and a third probe arranged sequentially along the flow direction of the gas-liquid two-phase flow. The first probe and the second probe are used to obtain the first gas phase true velocity; the second probe and the third probe are used to obtain the second gas phase true velocity, wherein the average value of the first gas phase true velocity and the second gas phase true velocity is the gas phase average true velocity.

[0244] Among them, such as Figure 7 The schematic diagram showing the probe placement allows us to obtain the true velocity U of the first gas phase based on the potential change parameters of the first and second probes and the distance between them. G1 The potential change parameter includes the time of potential change, specifically, the time of potential change from high level to low level, or from low level to high level.

[0245] Similarly, the true velocity U of the second gas phase is obtained based on the potential change parameters of the second and third probes and the distance between the second and third probes. G2 Furthermore, based on the true velocity U of the first gas phase... G1 Second gas phase true velocity U G2 The average true gas phase velocity U is obtained by taking the average value. G .

[0246] In this embodiment, the average true velocity of the gas phase in the gas-liquid two-phase flow is directly measured by the probe, which improves the efficiency of the measurement and the accuracy of the calculation of the measurement results.

[0247] In one embodiment, such as Figure 8 As shown, a method for dynamic monitoring of gas-liquid two-phase flow is provided, including:

[0248] S802, acquire the potential change parameters of the first conductivity probe, the second conductivity probe and the third conductivity probe.

[0249] S804, based on the setting interval length and potential change parameters between the first conductivity probe, the second conductivity probe and the third conductivity probe, at least two gas phase true velocities are obtained.

[0250] S806, the average true gas phase velocity is obtained based on at least two true gas phase velocities.

[0251] S808 obtains the initial flow rate of the gas-liquid two-phase flow through the flow unit in the measuring device.

[0252] S810 obtains the measured value of the apparent velocity of the liquid phase based on the average true velocity of the gas phase, the preset cavitation fraction, and the initial flow rate of the gas-liquid two-phase flow.

[0253] S812, based on the preset cavitation fraction, empirical value of P index, and liquid phase density, obtains the average density of the gas-liquid two-phase flow.

[0254] S814, based on the wall shear stress and the average density of the gas-liquid two-phase flow, the expression for the first shear stress is obtained.

[0255] S816, the second shear stress expression is obtained based on the mixing length and the average true velocity of the liquid phase in the mixing length model.

[0256] S818, based on the force balance condition of the shear stress in the first and second shear stress expressions, obtains the radial distribution of the liquid phase velocity.

[0257] S820, the apparent velocity of the liquid phase is calculated by integrating radially along the radial distribution of the liquid phase velocity.

[0258] S822, determine whether the measured value of the apparent velocity of the liquid phase is equal to the calculated value of the apparent velocity of the liquid phase. If yes, execute S824; otherwise, execute S826.

[0259] S824: Obtain the weighted average value of the first cavitation fraction based on the distribution parameters, gas phase drift velocity, and gas phase apparent velocity; obtain the weighted average value of the second cavitation fraction based on the preset cavitation fraction and P index; obtain the P index based on the weighted average value of the first cavitation fraction and the weighted average value of the second cavitation fraction; and execute S828.

[0260] The apparent velocity of the gas phase is obtained based on the average true velocity of the gas phase and the initial flow rate of the gas-liquid two-phase flow.

[0261] S826, If the measured value of the apparent liquid velocity is not equal to the calculated value of the apparent liquid velocity, adjust the value of the wall shear stress until the measured value of the apparent liquid velocity is equal to the calculated value of the apparent liquid velocity, and return to S814.

[0262] S828, based on the P index and the preset cavitation fraction, obtains the calculated value of the cavitation fraction and the calculated value of the gas-liquid two-phase flow density corresponding to the calculated value of the cavitation fraction.

[0263] S830, the initial value of the gas-liquid two-phase flow density is corrected based on the calculated value of the gas-liquid two-phase flow density to obtain the corrected value of the gas-liquid two-phase flow density.

[0264] S832, determine whether the deviation rate between the calculated value and the corrected value of the gas-liquid two-phase flow density is greater than or equal to a preset value. If yes, proceed to S834; otherwise, proceed to S844.

[0265] S834, the calculated flow rate of the gas-liquid two-phase flow is corrected based on the correction value of the gas-liquid two-phase flow density to obtain the corrected flow rate value of the gas-liquid two-phase flow.

[0266] S836, based on the flow rate correction value of the gas-liquid two-phase flow, obtain a new correction value for the gas-liquid two-phase flow density.

[0267] S838: Determine whether the deviation rate between the new corrected value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than a preset value. If yes, proceed to S840. If no, proceed to S842.

[0268] S840, based on the new correction value of the gas-liquid two-phase flow density or the correction value of the gas-liquid two-phase flow density, obtains the measurement result of the gas-liquid two-phase flow.

[0269] Taking the new corrected value of the gas-liquid two-phase flow density as an example, the target value of the gas-liquid two-phase flow rate is obtained based on the new corrected value of the gas-liquid two-phase flow density. The P index is calculated based on the target value of the gas-liquid two-phase flow rate and the average true velocity of the gas phase. The measurement result of the cavitation fraction in the measurement result is obtained based on the P index and the preset cavitation fraction.

[0270] like Figure 9 As shown, a total of 76 operating conditions were compared. The relative deviation rate between calculated and experimental values ​​did not exceed 20%. For the Ariyoshi bubble bed experiment, the statistical relative error and statistical root mean square error did not exceed ±9% and 15%, respectively. Compared with the original Clark drift flow model, the absolute values ​​of the maximum statistical relative error and statistical root mean square error decreased by approximately 42% and 27%, respectively. For the Nishi air lift pump experiment, the statistical relative error and statistical root mean square error did not exceed ±5% and 17%, respectively. Compared with Clark's drift flow model, the absolute values ​​of the maximum statistical relative error and statistical root mean square error decreased by 71% and 87%, respectively.

[0271] The results above demonstrate that the model is suitable for calculating the cavitation fraction in gas-liquid lead-bismuth two-phase flow. The model will be used in subsequent analyses of two-phase flows.

[0272] S842, continue to correct until the density deviation rate calculated after two consecutive corrections is less than the preset value. Then, select one of the gas-liquid two-phase flow density values ​​obtained after these two corrections and calculate the measurement result of the gas-liquid two-phase flow.

[0273] S844: Based on the correction value or the calculated value of the gas-liquid two-phase flow density, the measurement result of the gas-liquid two-phase flow is obtained.

[0274] In this embodiment, the average true velocity of the gas phase is obtained directly through a conductivity probe in the gas-liquid two-phase flow measurement device, rather than indirectly through other measurement methods. Based on the average true velocity of the gas phase, a preset cavitation fraction, and the initial flow rate of the gas-liquid two-phase flow, the measured value of the apparent velocity of the liquid phase is obtained. Then, based on the shear stress balance of the straight pipe wall in the gas-liquid two-phase flow measurement device, the calculated value of the apparent velocity of the liquid phase is obtained. Based on the measured and calculated values ​​of the apparent velocity of the liquid phase, when the measured value equals the calculated value, the P-index is obtained based on the calculated value of the apparent velocity, the preset cavitation fraction, distribution parameters, and gas phase drift velocity. Based on the P-index and the preset cavitation fraction, the calculated value of the cavitation fraction and the corresponding calculated value of the gas-liquid two-phase flow density are obtained. The calculated value of the gas-liquid two-phase flow density under one cycle is obtained. The initial value of the gas-liquid two-phase flow density is corrected based on the calculated value of the gas-liquid two-phase flow density to obtain the corrected value of the gas-liquid two-phase flow density. If the difference between the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than the preset value, the measurement result of the gas-liquid two-phase flow is obtained based on the calculated value of the gas-liquid two-phase flow density. By comparing the calculated value of the gas-liquid two-phase flow density and the corrected value, if the deviation rate between the two is less than the preset value, it means that the calculated density of the gas-liquid two-phase flow is the true density, thus improving the accuracy of the measurement results. This method, on the one hand, directly measures the average true velocity of the gas phase in the gas-liquid two-phase flow using a conductivity probe, improving measurement accuracy compared to indirect measurement methods in existing technologies. On the other hand, it compares the calculated and corrected values ​​of the gas-liquid two-phase flow density; if the deviation rate is less than a preset value, the measurement result of the gas-liquid two-phase flow is obtained based on the calculated value of the gas-liquid two-phase flow density, further improving the measurement results of gas-liquid two-phase flow parameters. This method can rapidly provide complete and comprehensive key parameter information by analyzing the gas-liquid two-phase flow caused by a heat transfer tube rupture accident in a lead-bismuth fast reactor steam generator.

[0275] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0276] Based on the same inventive concept, this application also provides a gas-liquid two-phase flow parameter measuring device for implementing the above-mentioned method for measuring gas-liquid two-phase flow parameters. The solution provided by this device is similar to the solution described in the above-described method. Therefore, the specific limitations of one or more embodiments of the gas-liquid two-phase flow parameter measuring device provided below can be found in the limitations of the gas-liquid two-phase flow parameter measuring method above, and will not be repeated here.

[0277] In one embodiment, such as Figure 10 As shown, a device for measuring parameters of a gas-liquid two-phase flow is provided, comprising: an acquisition module 1002, a first calculation module 1004, a second calculation module 1006, a first processing module 1008, a third calculation module 1010, and a second processing module 1012, wherein:

[0278] The acquisition module 1002 is used to acquire the average true velocity of the gas phase through the conductivity probe in the gas-liquid two-phase flow measurement device, and to obtain the initial value of the flow rate of the gas-liquid two-phase flow through the flow unit in the measurement device.

[0279] The first calculation module 1004 is used to obtain the measured value of the apparent velocity of the liquid phase based on the average true velocity of the gas phase, the preset cavitation fraction, and the initial value of the flow rate of the gas-liquid two-phase flow.

[0280] The second calculation module 1006 is used to obtain the calculated value of the apparent velocity of the liquid phase based on the wall shear stress on the inner side of the straight pipe in the measuring device, the average density of the gas-liquid two-phase flow, the average true velocity of the liquid phase, and the first and second shear stress expressions. The first shear stress expression is used to characterize the mechanical equilibrium relationship of the shear stress in the axial direction, and the second shear stress expression is constructed through a hybrid long model, which is used to characterize the relationship between the shear stress and the average true velocity of the liquid phase.

[0281] The first processing module 1008 is used to obtain the P-index based on the calculated value of the liquid phase apparent velocity, the preset cavitation fraction, the distribution parameters, and the gas phase drift velocity if the measured value of the liquid phase apparent velocity is equal to the calculated value of the liquid phase apparent velocity.

[0282] The third calculation module 1010 is used to obtain the calculated value of the cavitation fraction and the calculated value of the gas-liquid two-phase flow density corresponding to the calculated value of the cavitation fraction based on the P index and the preset cavitation fraction.

[0283] The second processing module 1012 is used to correct the initial value of the gas-liquid two-phase flow density based on the calculated value of the gas-liquid two-phase flow density, and to obtain the corrected value of the gas-liquid two-phase flow density. If the deviation rate between the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than a preset value, then the measurement result of the gas-liquid two-phase flow is obtained based on the calculated value of the gas-liquid two-phase flow density.

[0284] In one embodiment, the first processing module 1008 is further configured to obtain an expression for the weighted average value of the first cavitation fraction based on the distribution parameters, gas phase drift velocity, and gas phase apparent velocity, wherein the gas phase apparent velocity is obtained based on the gas phase average true velocity and the initial flow rate of the gas-liquid two-phase flow; an expression for the weighted average value of the second cavitation fraction is obtained based on the preset cavitation fraction and the P-index; and the P-index is obtained based on the expression for the weighted average value of the first cavitation fraction and the expression for the weighted average value of the second cavitation fraction.

[0285] In one embodiment, the device for measuring gas-liquid two-phase flow parameters further includes: a judgment module, used for...

[0286] If the deviation rate between the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is greater than or equal to a preset value, then the calculated value of the gas-liquid two-phase flow rate is corrected according to the corrected value of the gas-liquid two-phase flow density to obtain the corrected value of the gas-liquid two-phase flow rate; then a new corrected value of the gas-liquid two-phase flow density is obtained according to the corrected value of the gas-liquid two-phase flow rate; if the deviation rate between the new corrected value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than a preset value, then the measurement result of the gas-liquid two-phase flow is obtained according to the new corrected value of the gas-liquid two-phase flow density.

[0287] In one embodiment, the second calculation module 1006 is used to obtain the average density of the gas-liquid two-phase flow based on the preset cavitation fraction, empirical value of the P index, and liquid phase density; to obtain a first shear stress expression based on the wall shear stress and the average density of the gas-liquid two-phase flow; to obtain a second shear stress expression based on the mixing length and the average true liquid phase velocity in the mixing length model; to obtain the radial distribution of liquid phase velocity based on the force balance condition of the shear stress in the first and second shear stress expressions; and to obtain the calculated value of the apparent liquid phase velocity by integrating the radial distribution of liquid phase velocity.

[0288] In one embodiment, the second calculation module 1006 is further configured to adjust the value of the wall shear stress until the measured value of the liquid phase apparent velocity equals the calculated value of the liquid phase apparent velocity if the measured value of the liquid phase apparent velocity is not equal to the calculated value of the liquid phase apparent velocity.

[0289] In one embodiment, the acquisition module 1002 is further configured to acquire the potential change parameters of at least two conductivity probes; and to obtain the average true gas phase velocity based on the setting interval length between the at least two conductivity probes and the potential change parameters.

[0290] Each module in the aforementioned gas-liquid two-phase flow parameter measurement device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0291] In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 11 As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs in the non-volatile storage media. The database stores average real velocity data of the gas phase. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When executed by the processor, the computer program implements a method for measuring parameters of a gas-liquid two-phase flow.

[0292] Those skilled in the art will understand that Figure 11 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0293] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described above.

[0294] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0295] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps of the method described above.

[0296] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data shall comply with the relevant laws, regulations and standards of the relevant countries and regions.

[0297] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0298] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0299] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.< / j> < / f> < / j> < / j> < / j> < / j> < / j> < / j> < / j> < / j> < / j> < / j> < / j> < / j>

Claims

1. A method for measuring parameters of a gas-liquid two-phase flow, characterized in that, The method includes: The average true velocity of the gas phase is obtained by using the conductivity probe in the gas-liquid two-phase flow measurement device, and the initial flow rate of the gas-liquid two-phase flow is obtained by using the flow unit in the measurement device. The measured value of the apparent velocity of the liquid phase is obtained based on the average true velocity of the gas phase, the preset cavitation fraction, and the initial flow rate of the gas-liquid two-phase flow, wherein the preset cavitation fraction is obtained based on the average true velocity of the gas phase. Based on the wall shear stress on the inner side of the straight pipe in the measuring device, the average density of the gas-liquid two-phase flow, the average true velocity of the liquid phase, and the first and second shear stress expressions, the calculated value of the apparent velocity of the liquid phase is obtained. The first shear stress expression is used to characterize the mechanical equilibrium relationship of shear stress in the axial direction, and the second shear stress expression is constructed through a hybrid long model, which is used to characterize the relationship between shear stress and the average true velocity of the liquid phase. If the measured value of the apparent velocity of the liquid phase is equal to the calculated value of the apparent velocity of the liquid phase, then the P-index is obtained based on the calculated value of the apparent velocity of the liquid phase, the preset cavitation fraction, the distribution parameter, and the gas phase drift velocity. Based on the P-index and the preset cavitation fraction, the calculated value of the cavitation fraction and the calculated value of the gas-liquid two-phase flow density corresponding to the calculated value of the cavitation fraction are obtained. The initial value of the gas-liquid two-phase flow density is corrected based on the calculated value of the gas-liquid two-phase flow density to obtain the corrected value of the gas-liquid two-phase flow density. If the deviation rate between the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than a preset value, the measurement result of the gas-liquid two-phase flow is obtained based on the calculated value of the gas-liquid two-phase flow density. The step of obtaining the P-index based on the calculated value of the liquid phase apparent velocity, the preset cavitation fraction, distribution parameters, and gas phase drift velocity includes: An expression for the weighted average value of the first cavitation fraction is obtained based on the distribution parameters, the gas phase drift velocity, and the gas phase apparent velocity, wherein the gas phase apparent velocity is obtained based on the gas phase average true velocity and the initial flow rate of the gas-liquid two-phase flow. The expression for the weighted average value of the second void fraction is obtained based on the preset void fraction and P index; The P-index is obtained based on the expression for the weighted average of the first cavitation fraction and the expression for the weighted average of the second cavitation fraction. The method further includes: If the deviation rate between the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is greater than or equal to a preset value, then the calculated value of the gas-liquid two-phase flow rate is corrected according to the corrected value of the gas-liquid two-phase flow density to obtain the corrected value of the gas-liquid two-phase flow rate. A new corrected value for the density of the gas-liquid two-phase flow is obtained based on the flow rate correction value of the gas-liquid two-phase flow. If the deviation rate between the new corrected value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than a preset value, then the measurement result of the gas-liquid two-phase flow is obtained based on the new corrected value of the gas-liquid two-phase flow density.

2. The method according to claim 1, characterized in that, The calculation of the apparent velocity of the liquid phase based on the wall shear stress on the inner side of the straight pipe in the measuring device, the average density of the gas-liquid two-phase flow, the average true velocity of the liquid phase, and the expressions for the first and second shear stresses includes: The average density of the gas-liquid two-phase flow is obtained based on the preset cavitation fraction, empirical value of P index, and liquid phase density. The expression for the first shear stress is obtained based on the wall shear stress and the average density of the gas-liquid two-phase flow; The second shear stress expression is obtained based on the mixing length in the mixing length model and the average true velocity of the liquid phase. Based on the force balance condition of the shear stress in the first and second shear stress expressions, the radial distribution of the liquid phase velocity is obtained; The calculated value of the apparent velocity of the liquid phase is obtained by integrating the radial distribution of the liquid phase velocity along the radial direction.

3. The method according to claim 1, characterized in that, The method further includes: if the measured value of the apparent velocity of the liquid phase is not equal to the calculated value of the apparent velocity of the liquid phase, adjusting the value of the wall shear stress until the measured value of the apparent velocity of the liquid phase is equal to the calculated value of the apparent velocity of the liquid phase.

4. The method according to claim 1, characterized in that, The conductivity probe includes at least two conductivity probes, and the step of obtaining the average true velocity of the gas phase through the conductivity probes in the gas-liquid two-phase flow measurement device includes: Obtain the potential change parameters of the at least two conductivity probes; The average true velocity of the gas phase is obtained based on the set interval length between the at least two conductivity probes and the potential change parameters.

5. A device for measuring parameters of a gas-liquid two-phase flow, characterized in that, The measuring device includes: A Venturi tube, comprising a constriction tube, a throat, and a diffuser arranged sequentially along the flow direction of the gas-liquid two-phase flow; A straight pipe, which is concentrically connected to the diffuser tube; A conductivity probe, which is disposed on the inner side of the tube wall of the straight tube, is used to obtain the average true velocity of the gas phase; A flow unit is disposed on the outer side of the tube wall of the contraction tube and the throat tube, and is used to obtain the initial flow value of the gas-liquid two-phase flow. A processor for performing the steps of the method according to any one of claims 1 to 4.

6. A device for measuring parameters of a gas-liquid two-phase flow, characterized in that, The device includes: The acquisition module is used to acquire the average true velocity of the gas phase through the conductivity probe in the gas-liquid two-phase flow measurement device, and to obtain the initial flow value of the gas-liquid two-phase flow through the flow unit in the measurement device. The first calculation module is used to obtain the measured value of the apparent velocity of the liquid phase based on the average true velocity of the gas phase, the preset cavitation fraction, and the initial value of the flow rate of the gas-liquid two-phase flow. The second calculation module is used to obtain the calculated value of the apparent velocity of the liquid phase based on the wall shear stress on the inner side of the straight pipe in the measuring device, the average density of the gas-liquid two-phase flow, the average true velocity of the liquid phase, and the first and second shear stress expressions. The first shear stress expression is used to characterize the mechanical equilibrium relationship of the shear stress in the axial direction, and the second shear stress expression is constructed through a hybrid long model, which is used to characterize the relationship between the shear stress and the average true velocity of the liquid phase. The first processing module is used to obtain the P-index based on the calculated value of the apparent liquid phase velocity, the preset cavitation fraction, the distribution parameter, and the gas phase drift velocity if the measured value of the apparent liquid phase velocity is equal to the calculated value of the apparent liquid phase velocity. The third calculation module is used to obtain the calculated value of the cavitation fraction and the calculated value of the gas-liquid two-phase flow density corresponding to the calculated value of the cavitation fraction based on the P index and the preset cavitation fraction. The second processing module is used to correct the initial value of the gas-liquid two-phase flow density based on the calculated value of the gas-liquid two-phase flow density to obtain the corrected value of the gas-liquid two-phase flow density. If the deviation rate between the calculated value of the gas-liquid two-phase flow density and the corrected value of the gas-liquid two-phase flow density is less than a preset value, then the measurement result of the gas-liquid two-phase flow is obtained based on the calculated value of the gas-liquid two-phase flow density. The first processing module is further configured to: obtain an expression for the weighted average value of the first cavitation fraction based on the distribution parameters, the gas phase drift velocity, and the gas phase apparent velocity, wherein the gas phase apparent velocity is obtained based on the gas phase average true velocity and the initial flow rate of the gas-liquid two-phase flow; obtain an expression for the weighted average value of the second cavitation fraction based on the preset cavitation fraction and the P-index; and obtain the P-index based on the expression for the weighted average value of the first cavitation fraction and the expression for the weighted average value of the second cavitation fraction. The device further includes a judgment module, which is used to correct the calculated flow rate of the gas-liquid two-phase flow based on the correction value of the gas-liquid two-phase flow density if the deviation rate between the calculated value and the correction value of the gas-liquid two-phase flow density is greater than or equal to a preset value, thereby obtaining a corrected flow rate value for the gas-liquid two-phase flow; and to obtain a new corrected value for the gas-liquid two-phase flow density based on the corrected flow rate value; and to obtain the measurement result of the gas-liquid two-phase flow based on the new corrected value of the gas-liquid two-phase flow density if the deviation rate between the new corrected value and the correction value of the gas-liquid two-phase flow density is less than a preset value.

7. The apparatus according to claim 6, characterized in that, The second calculation module is also used for: The average density of the gas-liquid two-phase flow is obtained based on the preset cavitation fraction, empirical value of P index, and liquid phase density. The expression for the first shear stress is obtained based on the wall shear stress and the average density of the gas-liquid two-phase flow; The second shear stress expression is obtained based on the mixing length in the mixing length model and the average true velocity of the liquid phase. Based on the force balance condition of the shear stress in the first and second shear stress expressions, the radial distribution of the liquid phase velocity is obtained; The calculated value of the apparent velocity of the liquid phase is obtained by integrating the radial distribution of the liquid phase velocity along the radial direction.

8. The apparatus according to claim 6, characterized in that, The second calculation module is also used for: If the measured value of the apparent liquid phase velocity is not equal to the calculated value of the apparent liquid phase velocity, then the value of the wall shear stress is adjusted until the measured value of the apparent liquid phase velocity is equal to the calculated value of the apparent liquid phase velocity.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 4.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 4.

11. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 4.

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