Supercritical medium metering method and regulating device

Abstract

This invention discloses a supercritical medium metering method and regulating device. The metering method includes: S1, acquiring real-time state information of the metering medium and determining its real-time state; S2, metering the volumetric flow rate of the metering medium according to its different real-time states; and S3, calculating the mass flow rate using the medium density ρ, medium temperature, and the measured volumetric flow rate. This invention solves the problem of the narrow applicability of existing supercritical medium regulating methods.

Description

[Technical Field]

[0001] This invention relates to the field of metering and regulating fuel and other media in aerospace engines, and in particular to a method and device for metering and regulating supercritical media. [Background Technology]

[0002] As the Mach numbers of aerospace vehicles continue to increase and their flight environments become increasingly harsh, higher demands are placed on the active cooling of these vehicles. Active regenerative cooling (ADCU), as a cooling system for such engines, offers the possibility for various engines to adapt to increasingly harsh operating environments. The engine coolant in ADCU is generally the engine fuel, which is in a supercritical state under ultra-high pressure and ultra-high heat flux. Experimental studies on supersonic combustion have found that, under the same inflow conditions and equivalence ratio, supercritical kerosene has a 10%–15% higher combustion efficiency than liquid kerosene, and supercritical fuel can significantly improve combustion intensity and efficiency.

[0003] Supercritical fluids are fluids whose temperature and pressure are both above their critical state. Supercritical fluids possess many unique properties, such as viscosity, density, diffusion coefficient, and solvation ability, which are highly sensitive to changes in temperature and pressure. Specifically, in the supercritical state, their viscosity is close to that of a gas, while their density is close to that of a liquid. Supercritical fluids do not undergo phase changes during the entire flow and heat transfer process. At supercritical pressure, the fluid reaches a maximum temperature (called the critical temperature) as the temperature increases. Near this maximum, the properties of supercritical fluids become even more sensitive to temperature changes, and the heat transfer process at this point differs from conventional heat transfer. If the temperature continues to rise to a certain level, a series of chemical changes that affect heat transfer, such as cracking and coking, will occur.

[0004] In existing technologies, the flow rate of supercritical media is controlled by adjusting its cold-end flow rate. For example, in patent CN10595242B, the flow rate of supercritical water is controlled by a high-pressure metering pump before the inlet of the supercritical water generator. However, since the fuel flow rate required for active regenerative cooling in high-performance aerospace engines is inconsistent with the flow rate required for engine combustion, and both use the same fuel source, it is impossible to control the supercritical fuel flow rate by controlling the cold-end fuel flow rate. Therefore, it is necessary to meter and regulate the supercritical state.

[0005] However, due to the unique properties of supercritical fuels, the property laws and calculation methods of conventional fluids are not entirely applicable. Current technologies treat supercritical media as ideal gases but fail to account for the compressibility effect of supercritical fluids, leading to certain deviations in the prediction of property parameters and posing significant challenges to experimental and numerical studies. Currently, research on the flow characteristics and flow adjustment of supercritical fluids is relatively limited, and studies on the supercritical flow characteristics of mixture-type fuels are even rarer.

[0006] In practical engine applications, to broaden the engine's operating envelope and improve its performance, there are also requirements for metering media in liquid, gaseous, and subcritical states throughout the entire metering and regulation cycle. Existing metering methods cannot meet these requirements, so there is an urgent need for a metering and regulation device and method that can effectively meter and regulate media in supercritical and other states. [Summary of the Invention]

[0007] To address the aforementioned problems, this invention provides a supercritical medium metering and regulation method and apparatus, which can solve the problem of the narrow applicability of existing supercritical medium regulation methods.

[0008] The technical solution adopted in this invention is a supercritical medium metering method, the metering method comprising:

[0009] S1. Obtain the real-time status information of the metering medium and determine the real-time status of the metering medium accordingly.

[0010] S2. Measure the volumetric flow rate of the metering medium according to its different real-time conditions;

[0011] S2.1 When the real-time state is supercritical:

[0012] If the flow velocity u1 of the metering medium reaches the speed of sound a, then before the state changes, the volumetric flow rate is a constant that depends only on the throat area.

[0013] The flow velocity u1 of the metering medium is less than the speed of sound a. The volumetric flow rate is obtained based on the velocity u1 and the area S1.

[0014] S2.2 When the real-time state is gaseous:

[0015] When the velocity at the throat of the metering nozzle reaches velocity 'a', the volumetric flow rate of the medium is determined by the inlet pressure, temperature, and throat area.

[0016] If the velocity at the throat of the metering nozzle is less than the speed of sound a, then the volumetric flow rate of the medium is determined by the inlet and outlet pressures, temperature, throat area, medium compressibility factor z, and absolute viscosity μ.

[0017] S2.3 When the real-time state is liquid:

[0018] If the pressure Pc at the throat is less than the saturated vapor pressure of the medium at this temperature, the volumetric flow rate is a constant that depends only on the throat area before the state changes.

[0019] If the pressure Pc at the throat is greater than or equal to the saturated vapor pressure of the medium at this temperature, the volumetric flow rate of the medium can be determined by the inlet and outlet pressures, temperature, throat area, and absolute viscosity μ.

[0020] S3. Calculate the mass flow rate using the medium density ρ, medium temperature, and the measured volumetric flow rate.

[0021] Furthermore, in step S2, if the real-time state is between gaseous and liquid, it means that the temperature of the medium is within the critical temperature range under the current pressure. At this time, the inlet pressure is changed to make the medium state deviate from the critical range and become a definite state before measurement is performed.

[0022] Furthermore, in step S2, if the real-time state is between gaseous and liquid, it indicates that the temperature of the medium is within the critical temperature range under the current pressure. First, perform measurement according to step S2.3. After obtaining the measurement result, infer the gas-liquid ratio Xlm of the medium at this time through the inlet pressure Pin, inlet temperature Tin, and the bubble point and dew point of the current medium. Then, based on the gas-liquid ratio Xlm combined with the mathematical model of measuring moisture, correct the measured flow rate obtained in the previous step.

[0023] Furthermore, in step S2.1, based on the measured total temperature and total pressure before and after supercritical kerosene metering, the enthalpy value h1 and entropy value S of the corresponding inlet metering medium are obtained by using the generalized corresponding state method through the total temperature and total pressure before metering. Setting the entropy value to remain constant, the enthalpy value hout of the outlet metering medium can be obtained again by using the generalized corresponding state method through the total temperature and total pressure after metering. The flow velocity u1 of the fluid can be obtained by using the change of enthalpy values ​​between the two states.

[0024] Furthermore, in step S2.2, it is determined whether the velocity at the throat of the flow channel reaches the speed of sound based on the ratio of the inlet pressure to the outlet pressure and the medium temperature.

[0025] Furthermore, in step S2.3, based on the inlet pressure Pin and inlet temperature Tin, and combined with the structural parameters of the metering nozzle, it is determined whether the pressure Pc at the throat is lower than the saturated vapor pressure of the metering medium at this temperature.

[0026] The second technical solution adopted in this invention is a supercritical medium metering and regulating device, comprising a cylindrical body and a metering nozzle arranged in a through manner, wherein the metering nozzle has a structure of first contracting and then expanding; the outer port of the cylindrical body is the metering medium inlet, and the outer port of the metering nozzle is the metering medium outlet; a pre-metering temperature sensor and a pre-metering pressure sensor are connected at the junction of the cylindrical body and the metering nozzle, and a post-metering temperature sensor and a post-metering pressure sensor are connected at the metering medium outlet.

[0027] Furthermore, an adjusting cone is installed inside the metering nozzle, with the tip of the adjusting cone pointing towards the outlet of the metering medium. The tail end of the adjusting cone is connected in sequence to a control connecting shaft and an electrical signal-displacement actuator. A sealing ring is installed between the electrical signal-displacement actuator and the metering nozzle to isolate the two.

[0028] Furthermore, multiple metering nozzles are connected in parallel, and a shut-off valve is added before each metering nozzle.

[0029] Furthermore, the throat area at the metering throat of the metering nozzle is adjustable.

[0030] The beneficial effects of this invention are that, before metering adjustment, by analyzing the medium's pressure and temperature detection values ​​to determine the medium's state and adopting corresponding metering adjustment schemes, the measurable range of the medium is greatly expanded. This is equivalent to expanding the controllable working envelope of the aircraft or other corresponding adjustment objects, and improving combustion efficiency, thus simultaneously enhancing performance and economy. Furthermore, by setting threshold ranges, this invention determines the critical range and minimizes complex operating conditions near the critical point, reducing system complexity, simplifying control calculations, and improving metering accuracy. [Attached Image Description]

[0031] Figure 1 This is a schematic diagram of the structure of a supercritical medium metering device according to the present invention;

[0032] Figure 2 This is a schematic diagram of the method flow for a supercritical medium metering method according to the present invention;

[0033] Figure 3 This is a schematic diagram of the metering device in Example 2.

[0034] The components include: 1. Metering medium inlet; 2. Cylinder; 3. Metering medium outlet; 4. Metering nozzle; 5. Pre-metering pressure sensor; 6. Pre-metering temperature sensor; 7. Post-metering pressure sensor; 8. Post-metering temperature sensor; 9. Electrical signal and displacement actuator; 10. Control connecting shaft; 11. Metering throat; 12. Adjusting cone; and 13. Sealing ring.

Detailed Implementation Methods

[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0036] This invention provides a method and device for metering supercritical media, the metering method comprising:

[0037] S1. Obtain real-time status information of the metering medium and determine its real-time status accordingly. The method for obtaining real-time status information of the metering medium is as follows: Based on the type of the metering medium, obtain its physical properties, namely, its critical pressure value, critical temperature value, and gas-liquid separation point; the metering medium may be, for example, water or kerosene. Obtain the real-time status information of the metering medium using temperature and pressure sensors; the real-time status information includes the temperature and pressure of the metering medium.

[0038] S2. Measure the volumetric flow rate of the metering medium according to its different real-time conditions;

[0039] S2.1 When the real-time state is supercritical:

[0040] If the flow velocity u1 of the metering medium reaches the speed of sound a, then before the state changes, the volumetric flow rate is a constant that depends only on the throat area.

[0041] The flow velocity u1 of the metering medium is less than the speed of sound a. The volumetric flow rate is obtained based on the velocity u1 and the area S1.

[0042] S2.2 When the real-time state is gaseous:

[0043] If the velocity at the throat of the metering nozzle 4 reaches the speed of sound a, the volumetric flow rate of the medium is determined by the inlet pressure, temperature and throat area.

[0044] If the velocity at the throat of the metering nozzle 4 is less than the speed of sound a, then the volumetric flow rate of the medium is determined by the inlet and outlet pressures, temperature, throat area, medium compressibility factor z, and absolute viscosity μ.

[0045] S2.3 When the real-time state is liquid:

[0046] If the pressure Pc at the throat is less than the saturated vapor pressure of the medium at this temperature, the volumetric flow rate is a constant that depends only on the throat area before the state changes.

[0047] If the pressure Pc at the throat is greater than or equal to the saturated vapor pressure of the medium at this temperature, the volumetric flow rate of the medium can be determined by the inlet and outlet pressures, temperature, throat area, and absolute viscosity μ.

[0048] S3. Calculate the mass flow rate using the medium density ρ, medium temperature, and the measured volumetric flow rate.

[0049] Before metering adjustment, this invention analyzes the medium's state by measuring its pressure and temperature, and then adopts a corresponding metering adjustment scheme. This significantly expands the measurable range of the medium, essentially extending the controllable working envelope of aircraft or other corresponding adjustment objects, and improving combustion efficiency—that is, simultaneously enhancing performance and economy. By setting threshold ranges, this invention determines the critical range and minimizes complex operating conditions near the critical point, reducing system complexity, simplifying control calculations, and improving metering accuracy.

[0050] In some embodiments, in step S2, if the real-time state is between gaseous and liquid, it indicates that the temperature of the medium is within the critical temperature range under the current pressure. At this time, the inlet pressure is changed to make the medium state deviate from the critical range and become a definite state before measurement is performed.

[0051] For example, in step 101, the critical pressure point, critical temperature point, and gas-liquid separation point are replaced with a judgment threshold range. For example, the upper limit of the critical pressure is 2.4 MPa, the lower limit of the critical pressure is 2.2 MPa, the upper limit of the critical temperature is 350°C, the lower limit of the critical temperature is 330°C, the lower limit of the gas-liquid separation point is the bubble point, and the upper limit of the gas-liquid separation point is the dew point, etc.

[0052] Before making judgments in steps 131, 142, 151, and 161, it is first determined whether the current state is within the judgment threshold range;

[0053] If the current state is not within the judgment threshold range, then the current state is determined and the judgment operation can be performed normally.

[0054] If the current state is within the judgment interval, it means that the current state is near the critical point between states. At this time, feedback is sent to the controller, and the current state is changed, such as by changing the inlet pressure, so that the system deviates from the critical interval and becomes a definite state before making a judgment.

[0055] In some embodiments, in step 2, if the real-time state is between gaseous and liquid, it indicates that the temperature of the medium is within the critical temperature range under the current pressure. First, the measurement is performed according to step s2.3. After obtaining the measurement result, the gas-liquid ratio Xlm of the medium is inferred by the inlet pressure Pin, the inlet temperature Tin, and the bubble point and dew point of the current medium. Then, the measured flow rate obtained in step s2.3 is corrected based on the gas-liquid ratio Xlm combined with the mathematical model of measuring moisture.

[0056] For example, in step 131, when the medium temperature and pressure are between the bubble point and dew point of the current state, measurement is performed according to step 161. The gas-liquid ratio Xlm of the medium at this time is inferred based on the inlet pressure Pin, inlet temperature Tin, and the bubble point and dew point of the current state. Then, the flow rate obtained in step 171 is corrected based on the gas-liquid ratio Xlm combined with a mathematical model for measuring moisture, such as the Murdock model or the Lin Zonghu model. This allows for relatively accurate measurement of the gas-liquid mixed medium flow rate, resulting in higher measurement accuracy throughout the entire process.

[0057] In some embodiments, in step S2.1, based on the measured total temperature and total pressure before and after supercritical kerosene metering, the enthalpy value h1 and entropy value S of the corresponding inlet metering medium are obtained by using the generalized corresponding state method through the total temperature and total pressure before metering. The entropy value is set to remain unchanged, and the enthalpy value hout of the outlet metering medium is obtained again by using the generalized corresponding state method through the total temperature and total pressure after metering. The flow velocity u1 of the fluid can be obtained by using the change of enthalpy values ​​between the two states.

[0058] In some embodiments, in step S2.2, it is determined whether the velocity at the throat of the flow channel reaches the speed of sound based on the ratio of the inlet pressure to the outlet pressure and the medium temperature.

[0059] In some embodiments, in step S2.3, based on the inlet pressure Pin and the inlet temperature Tin, and in conjunction with the metering nozzle structural parameters, it is determined whether the pressure Pc at the throat is lower than the saturated vapor pressure of the medium at this temperature.

[0060] This invention also provides a supercritical medium metering and regulating device, applied to a supercritical medium metering method, such as... Figure 1 As shown, it includes a cylindrical body 2 and a metering nozzle 4 that are arranged in a through manner. The metering nozzle 4 has a structure that first contracts and then expands. The outer port of the cylindrical body 2 is the metering medium inlet 1, and the outer port of the metering nozzle 4 is the metering medium outlet 3. A pre-metering temperature sensor 6 and a pre-metering pressure sensor 5 are connected at the junction of the cylindrical body 2 and the metering nozzle 4. A post-metering temperature sensor 8 and a post-metering pressure sensor 7 are connected to the metering medium outlet 3.

[0061] In some embodiments, such as Figure 3 As shown, an adjusting cone 12 is provided inside the metering nozzle 4. The tip of the adjusting cone 12 points towards the outlet 3 of the metering medium. The tail end of the adjusting cone 12 is sequentially connected to a control connecting shaft 10 and an electrical signal-displacement actuator 9. A sealing ring 13 is provided between the electrical signal-displacement actuator 9 and the metering nozzle 4 to isolate them. By adding an adjusting component, this invention can adjust the flow rate to the required value when the medium is in any state, solving the problem of mismatch between the fuel required for active cooling and the fuel required for combustion, and greatly improving engine performance.

[0062] In some embodiments, multiple metering nozzles 4 are arranged in parallel, with a shut-off valve added before each metering nozzle 4. The flow rate of each metering nozzle 4 is controlled by controlling the opening and closing of the shut-off valves. The controller can receive metering device status information and desired indicator information of the controlled object, calculate the shut-off valve control signal through a preset algorithm, and adjust the metering flow rate by controlling the opening and closing of each shut-off valve.

[0063] In some embodiments, the throat area at the metering throat 11 of the metering nozzle 4 is adjustable. The nozzle is made of a deformable material, and external structural forces can deform the throat. The controller receives metering device status information and desired index information of the controlled object, calculates a control signal through a preset algorithm, and adjusts the metering flow rate by controlling the throat area of ​​the metering nozzle.

[0064] The working process of the supercritical medium metering and regulating device of the present invention is as follows: Figure 2 As shown, it includes:

[0065] 101- Determine the critical pressure value, critical temperature value, and gas-liquid separation point based on the physical properties of the metering medium;

[0066] 111 - Obtain the status information of the metering device and the metering medium based on the temperature sensor before metering, the pressure sensor before metering, the temperature sensor after metering, and the pressure sensor after metering.

[0067] 121 - Send the status information of the metering device to the controller;

[0068] 131 - The controller compares the status information of the metering device with the critical pressure value, critical temperature value, and gas-liquid separation point to determine the state of the medium. If the medium is in a supercritical state, step 141 is executed; if the medium is in a gaseous state, step 151 is executed; if the medium is in a liquid state, step 161 is executed.

[0069] 141- Based on the measured total temperature and pressure before and after supercritical kerosene metering, the enthalpy hin and entropy S of the corresponding inlet kerosene are obtained by using the generalized corresponding state rule through the total temperature and pressure before metering. With the entropy value remaining unchanged, the enthalpy houtlet can be obtained by using the generalized corresponding state rule through the total temperature and pressure after metering. The flow velocity u1 and sound speed a are obtained by using the change in enthalpy between the two states.

[0070] 142 - Determine whether the flow velocity u1 has reached the speed of sound a. If not, proceed to step 143; otherwise, proceed to step 144.

[0071] 143 - Calculate the volumetric flow rate based on the velocity u1 and area S1;

[0072] 144 - Before the change of state, the volumetric flow rate is a constant that depends only on the throat area;

[0073] 151 - Determine whether the velocity at the throat of the flow channel reaches the speed of sound based on the ratio of the inlet and outlet pressures Pin and Pout. If it reaches the speed of sound, proceed to step 152; otherwise, proceed to step 153.

[0074] 152 - The volumetric flow rate of the medium is determined by the inlet pressure, temperature, and throat area;

[0075] 153 - The volumetric flow rate of the medium is determined by the inlet and outlet pressure, temperature, throat area, medium compressibility factor z, and absolute viscosity μ;

[0076] 161-Based on the inlet pressure Pin and inlet temperature Tin, and combined with the metering nozzle structure parameters, determine whether the throat pressure Pc is lower than the saturated vapor pressure of the medium at this temperature. If it is lower than the saturated vapor pressure, proceed to step 162; if it is higher than the saturated vapor pressure, proceed to step 163.

[0077] 162 - Before the change of state, the volumetric flow rate is a constant that depends only on the throat area;

[0078] 163 - The volumetric flow rate of the medium is determined by the inlet and outlet pressure, temperature, throat area, and absolute viscosity μ;

[0079] 171 - The mass flow rate is calculated by interpolating the medium density ρ using the outlet temperature Tout and the volumetric flow rate obtained from the metering.

[0080] Example 1

[0081] Taking the liquid, gas, and supercritical medium metering method of RP-3 aviation kerosene as an example, since RP-3 aviation kerosene is a mixture, its critical pressure is between 2.2 and 2.4 MPa, and its critical temperature range is 332.1 to 348.9℃. Physical properties such as bubble point and dew point temperature, saturated vapor pressure, etc. will change under different pressures.

[0082] Select a point within the critical temperature range as the critical temperature, for example, Tc = 340℃; select a point within the critical pressure range as the critical pressure, for example, Pc = 2.3MPa; select a gas-liquid separation point between the bubble point and dew point at the same pressure, for example, the average temperature under the same pressure.

[0083] The electronic controller collects electrical signals from the pressure and temperature sensors before and after metering to obtain the pressures Pin, Pout and Tin, Tout of the metering inlet and outlet media, respectively; the status information of the metering device is sent to the controller; the controller compares the status information of the metering device with the critical pressure value, critical temperature value, and gas-liquid separation point to determine the status of the medium.

[0084] If the medium is in a supercritical state, based on the measured total temperature and pressure of the supercritical kerosene before and after metering, the enthalpy hin and entropy S of the corresponding inlet kerosene can be obtained by using the generalized corresponding state rule through the total temperature and pressure before metering. With the entropy value remaining unchanged, the enthalpy houtlet can be obtained by using the generalized corresponding state rule again through the total temperature and pressure after metering. Using the change in enthalpy between the two states, the flow velocity u1 and the speed of sound a can be obtained. It is then determined whether the flow velocity u1 reaches the speed of sound a. If not, the volumetric flow rate can be obtained based on the velocity u1 and the area S1. Otherwise, before the state changes, the volumetric flow rate is a constant that is only related to the throat area.

[0085] If the medium is gaseous, determine whether the velocity at the throat of the flow channel reaches the speed of sound based on the ratio of the inlet and outlet pressures Pin and Pout. If it reaches the speed of sound, determine the volumetric flow rate of the medium by the inlet pressure, temperature, and throat area. If it does not reach the speed of sound, determine the volumetric flow rate of the medium by the inlet and outlet pressures, temperature, throat area, medium compressibility factor z, and absolute viscosity μ.

[0086] If the medium is liquid, the pressure Pc at the throat is determined based on the inlet pressure Pin and inlet temperature Tin, combined with the structural parameters of the metering nozzle. If it is lower than the saturated vapor pressure of the medium at this temperature, the volumetric flow rate is a constant that is only related to the throat area before the state changes. If it is higher than the saturated vapor pressure, the volumetric flow rate of the medium is determined by the inlet and outlet pressures, temperatures, throat area, and absolute viscosity μ.

[0087] Finally, the mass flow rate is calculated using the medium density ρ obtained from the outlet temperature Tout and the volumetric flow rate measured.

[0088] Example 2

[0089] Combination Figure 2 and Figure 3 As shown, another supercritical medium metering and regulating device provided by the present invention includes a through-type cylinder 2 and a metering nozzle 4, wherein the metering nozzle 4 has a structure that first contracts and then expands; the outer port of the cylinder 2 is the metering medium inlet 1, and the outer port of the metering nozzle 4 is the metering medium outlet 3; a pre-metering temperature sensor 6 and a pre-metering pressure sensor 5 are connected at the junction of the cylinder 2 and the metering nozzle 4, and a post-metering temperature sensor 8 and a post-metering pressure sensor 7 are connected to the metering medium outlet 3. An adjusting cone 12 is provided inside the metering nozzle 4, the tip of the adjusting cone 12 pointing towards the metering medium outlet 3, and the tail end of the adjusting cone 12 is sequentially connected to a control connecting shaft 10 and a displacement actuator 9.

[0090] After measuring the flow rate at the current state, the controller receives the expected index information of the controlled object and calculates the control signal through a preset algorithm; by controlling the throat area of ​​the metering nozzle, the metering flow rate is adjusted.

[0091] Before metering adjustment, this invention analyzes the medium's state by measuring its pressure and temperature. For different states—supercritical, gaseous, or liquid—it employs corresponding metering adjustment methods, significantly expanding the measurable range of the medium. This is equivalent to extending the controllable operating envelope of an aircraft or other similar adjustment object, and improving combustion efficiency, thus simultaneously enhancing performance and economy. By setting threshold ranges, this invention determines the critical range and minimizes complex operating conditions near the critical point, reducing system complexity, simplifying control calculations, and improving metering accuracy.

[0092] This invention solves the problem of mismatch between the fuel required for active cooling and the fuel required for combustion by adding an adjustment component, namely, setting multiple metering nozzles 4 in parallel and adding a shut-off valve in front of each metering nozzle 4, and controlling the flow rate of each metering nozzle 4 by controlling the opening and closing of the shut-off valve; it also solves the problem of mismatch between the fuel required for active cooling and the fuel required for combustion by designing the throat area at the metering throat 11 of the metering nozzle 4 to be adjustable, so that the flow rate can be adjusted to the required value when the medium is in any state, thus greatly improving the engine performance.

[0093] This invention employs a modified method to achieve relatively accurate metering of the flow rate of gas-liquid mixtures, resulting in higher metering precision throughout the entire process. Besides its applications in aerospace engine fuel flow regulation, this invention can also be used in natural gas metering and regulation, the petroleum industry, supercritical generator sets, and other scenarios involving flow metering and regulation of media under different states, demonstrating its wide applicability.

Claims

1. A method for metering supercritical media, characterized in that, The measurement method includes: S1. Obtain the real-time status information of the metering medium and determine the real-time status of the metering medium accordingly. S2. Measure the volumetric flow rate of the metering medium according to its different real-time conditions; S2.1 When the real-time state is supercritical: If the flow velocity u1 of the metering medium reaches the speed of sound a, then before the state changes, the volumetric flow rate is a constant that depends only on the throat area. The flow velocity u1 of the metering medium is less than the speed of sound a. The volumetric flow rate is obtained based on the velocity u1 and the area S1. S2.2 When the real-time state is gaseous: When the velocity at the throat of the metering nozzle (4) reaches velocity a, the volumetric flow rate of the medium is determined by the inlet pressure, temperature and throat area. If the velocity at the throat of the metering nozzle (4) is less than the speed of sound a, then the volumetric flow rate of the medium is determined by the inlet and outlet pressures, temperature, throat area, medium compressibility factor z, and absolute viscosity μ. S2.3 When the real-time state is liquid: If the pressure Pc at the throat is less than the saturated vapor pressure of the medium at this temperature, the volumetric flow rate is a constant that depends only on the throat area before the state changes. If the pressure Pc at the throat is greater than or equal to the saturated vapor pressure of the medium at this temperature, the volumetric flow rate of the medium can be determined by the inlet and outlet pressures, temperature, throat area, and absolute viscosity μ. S3. Calculate the mass flow rate using the medium density ρ, medium temperature, and the measured volumetric flow rate.

2. The supercritical medium metering method as described in claim 1, characterized in that, In step S2, if the real-time state is between gaseous and liquid, it means that the temperature of the medium is within the critical temperature range under the current pressure. At this time, the inlet pressure is changed to make the medium state deviate from the critical range and become a definite state before measurement is performed.

3. The supercritical medium metering method as described in claim 1, characterized in that, In step S2, if the real-time state is between gaseous and liquid, it means that the temperature of the medium is within the critical temperature range under the current pressure. First, perform measurement according to step S2.

3. After obtaining the measurement result, infer the gas-liquid ratio Xlm of the medium at this time by using the inlet pressure Pin, inlet temperature Tin, bubble point and dew point of the current medium. Then, based on the gas-liquid ratio Xlm combined with the mathematical model of measuring moisture, correct the metering flow rate obtained in the previous step.

4. The supercritical medium metering method as described in claim 1, characterized in that, In step S2.1, based on the measured total temperature and pressure before and after supercritical kerosene metering, the enthalpy h1 and entropy S of the corresponding inlet metering medium are obtained by using the generalized corresponding state method through the total temperature and pressure before metering. Setting the entropy value to remain constant, the enthalpy hout of the outlet metering medium can be obtained again by using the generalized corresponding state method through the total temperature and pressure after metering. The flow velocity u1 of the fluid can be obtained by using the change in enthalpy between the two states.

5. The supercritical medium metering method as described in claim 1, characterized in that, In step S2.2, the velocity at the throat of the flow channel is determined based on the ratio of the inlet pressure to the outlet pressure and the medium temperature.

6. The supercritical medium metering method as described in claim 1, characterized in that, In step S2.3, based on the inlet pressure Pin and inlet temperature Tin, and combined with the structural parameters of the metering nozzle, it is determined whether the pressure Pc at the throat is lower than the saturated vapor pressure of the metering medium at this temperature.

7. A supercritical medium metering and regulating device, characterized in that, The method is applied to any one of the supercritical medium metering methods as described in claims 1-6, and includes a cylindrical body (2) and a metering nozzle (4) that are arranged in a through manner. The metering nozzle (4) has a structure that first contracts and then expands. The outer port of the cylindrical body (2) is the metering medium inlet (1), and the outer port of the metering nozzle (4) is the metering medium outlet (3). A pre-metering temperature sensor (6) and a pre-metering pressure sensor (5) are connected at the junction of the cylindrical body (2) and the metering nozzle (4), and a post-metering temperature sensor (8) and a post-metering pressure sensor (7) are connected at the metering medium outlet (3).

8. The supercritical medium metering and regulating device as described in claim 7, characterized in that, An adjusting cone (12) is provided inside the metering nozzle (4). The tip of the adjusting cone (12) points to the metering medium outlet (3). The tail end of the adjusting cone (12) is connected in sequence to a control connecting shaft (10) and an electrical signal-displacement actuator (9). A sealing ring (13) is provided between the electrical signal-displacement actuator (9) and the metering nozzle (4) to isolate the two.

9. A supercritical medium metering and regulating device as described in claim 7 or 8, characterized in that, Multiple metering nozzles (4) are connected in parallel, and a shut-off valve is added in front of each metering nozzle (4).

10. A supercritical medium metering and regulating device as described in claim 7 or 8, characterized in that, The throat area at the metering throat (11) of the metering nozzle (4) is adjustable.

Images