Method, device and medium for calculating minimum continuous heat flow of fuel centrifugal pump

Abstract

This invention proposes a method, apparatus, and medium for calculating the minimum continuous heat flow of a fuel centrifugal pump. The invention aims to address the technical problem in existing minimum continuous heat flow calculations that fail to consider the coupled effects of fuel vaporization margin and viscosity-temperature characteristics, leading to easy vaporization and overheating under low flow conditions. This invention obtains operating parameters and fuel property data, determines the dynamic ejector coefficient based on the ejector working pressure ratio and dynamic fuel property characteristics, determines the dynamically permissible temperature rise constrained by vaporization, viscosity, and structural limitations based on saturated vapor pressure characteristics and local minimum pressure, corrects power loss based on viscosity-temperature characteristics, and iteratively solves for the minimum continuous heat flow by establishing a specific enthalpy heat balance relationship. This invention can simultaneously satisfy thermal balance, anti-vaporization, and pump performance constraints, and is applicable to low flow protection, thermal safety design, and control protection of fuel centrifugal pump systems.

Description

Technical Field

[0001] This invention relates to the field of fluid machinery and pump thermal management technology, and in particular to a method, apparatus and medium for calculating the minimum continuous heat flow of a fuel centrifugal pump. Background Technology

[0002] Centrifugal fuel pumps are widely used in fuel supply systems for aircraft engines, marine power systems, and fuel supply systems for ground-based gas turbines. In actual operation, when the system's required flow rate is lower than the pump's rated flow rate, the centrifugal fuel pump inevitably operates under low-flow, throttling, or bypass recirculation conditions. Under these conditions, the portion of the pump shaft power that cannot be converted into effective pressure energy is transferred to the fuel as heat, causing the fuel temperature inside the pump to rise.

[0003] To address heat dissipation issues under low-flow conditions, existing fuel centrifugal pump systems typically incorporate an ejector at the pump outlet. A portion of the high-pressure fuel at the pump outlet is used as the primary flow to enter the ejector, entraining low-pressure fuel and creating a mixed reflux. This increases the fuel flow through the pump body, carrying away the heat generated within the pump. In engineering design, it is necessary to determine the minimum continuous heat flux required for the pump to operate safely and continuously, serving as the basis for low-flow protection thresholds and bypass valve control.

[0004] Existing methods for calculating minimum continuous heat flow typically determine the ejector coefficient under design or single test conditions and perform heat balance calculations using fixed fuel specific heat capacity and fixed pump efficiency. Specifically, traditional methods simplify pump power loss to a constant product of specific heat capacity, flow rate, and allowable temperature rise. The ejector coefficient is determined separately by the pressure ratio or flow rate ratio, and the allowable temperature rise is preset to a fixed safe temperature rise value. While some methods can determine the ejector's injection flow rate or ejector coefficient based on pressure relationships, their focus is primarily on the ejector body flow rate or the energy balance of the gas / vapor system. They lack specific correction algorithms for the dynamic changes in the vaporization boundary of liquid fuel after heating within the pump, the changes in pump net positive suction head (NPSH) with temperature, the changes in pump efficiency caused by fuel viscosity variations, and the changes in specific enthalpy after mixing return fuel with fresh fuel.

[0005] Therefore, there is an urgent need for a method, device, and medium for calculating the minimum continuous heat flow of a fuel centrifugal pump to solve the problems existing in the current technology. Summary of the Invention

[0006] This invention provides a method, apparatus, and medium for calculating the minimum continuous heat flow of a fuel centrifugal pump. Existing methods for calculating the minimum continuous heat flow of a fuel centrifugal pump only correct the ejector coefficient based on the pressure ratio or flow ratio, without incorporating the fuel vaporization margin and viscosity-temperature characteristics into the thermal balance model. This results in insufficient accuracy of the calculation results under low flow and high temperature conditions, and poses risks such as localized fuel vaporization or pump overheating.

[0007] The core technology of this invention is to calculate the dynamic allowable temperature rise that is limited by vaporization, viscosity and structural constraints by combining the saturated vapor pressure of fuel and the local minimum pressure in the pump. Based on the viscosity-temperature characteristics of fuel, the pump power loss and ejector coefficient are dynamically corrected, and the minimum continuous heat flow is solved iteratively by establishing the specific enthalpy mixing heat balance equation using the specific heat capacity integral.

[0008] In a first aspect, the present invention provides a method for calculating the minimum continuous heat flow of a fuel centrifugal pump, the method comprising the following steps:

[0009] Acquire pressure, flow, temperature, and fuel properties data during the operation of the fuel centrifugal pump system; The working pressure ratio of the ejector is calculated based on the pressure parameters, and the dynamic physical property characteristics of the fuel are determined based on the fuel physical property data. The dynamic physical property characteristics include at least the viscosity characteristics and the vaporization margin characteristics. The dynamic ejection coefficient of the ejector is determined based on the working pressure ratio and dynamic physical property characteristic number, and the ejection return flow rate is calculated based on the dynamic ejection coefficient. Based on the relationship between fuel saturated vapor pressure and temperature and the local minimum pressure inside the pump, the dynamic allowable temperature rise, which is jointly limited by vaporization constraints, viscosity constraints, and structural constraints, is determined. The power loss of the fuel centrifugal pump is corrected based on the viscosity-temperature characteristics in the fuel physical property data to obtain the dynamic power loss. The specific enthalpy heat balance relationship is established based on the ejector return flow rate, dynamic power loss, and specific heat capacity characteristics in the fuel physical property data. Combined with the dynamic allowable temperature rise, the minimum continuous heat flow rate of the fuel centrifugal pump is obtained by iterative solution.

[0010] Furthermore, the viscosity characteristic number is determined based on the ratio of the fuel kinematic viscosity at the current mixing temperature to the reference kinematic viscosity; the vaporization margin characteristic number is determined based on the ratio of the difference between the local minimum pressure in the pump, the fuel saturated vapor pressure at the current mixing temperature, and the preset safety pressure margin to the reference pressure difference.

[0011] Furthermore, the dynamic ejection coefficient of the ejector is determined based on the working pressure ratio and dynamic physical property characteristic number, including: The working pressure ratio, viscosity characteristic number, and vaporization margin characteristic number are input into a pre-constructed multivariate coupling correction function, interpolation model, or calibration mapping table to calculate the dynamic ejection coefficient; or The dynamic ejection coefficient is obtained by multiplicatively correcting the reference ejection coefficient using pressure ratio correction term, viscosity correction term and vaporization margin correction term. When the vaporization margin characteristic number is lower than the preset vaporization margin threshold, the dynamic ejection coefficient is derated or a protection action is triggered.

[0012] Furthermore, based on the relationship between fuel saturated vapor pressure and temperature, and the local minimum pressure within the pump, the dynamically permissible temperature rise, constrained by vaporization, viscosity, and structural constraints, is determined, including: The local minimum pressure inside the pump can be calculated based on the inlet pressure of the fuel centrifugal pump, the pressure drop in the suction line and the pressure drop at the impeller inlet, or the local minimum pressure inside the pump can be obtained directly through a pressure sensor. Based on the relationship between saturated vapor pressure and temperature and the preset safety pressure margin, the vaporization limit temperature at which vaporization does not occur is calculated, and the allowable temperature rise for vaporization constraint is calculated from the vaporization limit temperature. The viscosity limit for permissible temperature rise is calculated by back-calculating the minimum permissible viscosity and the viscosity-temperature characteristics of the fuel. The minimum value among the allowable temperature rise due to vaporization constraint, the allowable temperature rise due to preset structure, and the allowable temperature rise due to viscosity limitation is determined as the dynamic allowable temperature rise.

[0013] Furthermore, when the local minimum pressure inside the pump minus the preset safety pressure margin is less than or equal to the saturated vapor pressure corresponding to the current temperature, it is determined that the current operating condition does not meet the conditions for continuous safe operation, and the minimum continuous heat flow is increased to the protection flow or a vaporization risk alarm is issued.

[0014] Furthermore, the power loss of the fuel centrifugal pump is corrected based on the viscosity-temperature characteristics in the fuel property data to obtain the dynamic power loss, including: Determine the average viscosity within the temperature range from the inlet to the outlet of the fuel centrifugal pump; The pump's baseline efficiency is corrected based on the average viscosity utilization efficiency viscosity correction factor to obtain the corrected efficiency. The dynamic power loss is calculated based on the pump input power and the corrected efficiency.

[0015] Furthermore, based on the ejector return flow rate, dynamic power loss, and specific heat capacity characteristics in the fuel physical property data, a specific enthalpy heat balance relationship is established. Combined with the dynamic allowable temperature rise, the minimum continuous heat flow rate of the fuel centrifugal pump is iteratively solved, including: The specific enthalpy of fuel is obtained by integrating the specific heat capacity at constant pressure in the fuel physical property data over the temperature range. The mixing enthalpy at the pump inlet is calculated based on the mass flow rate and specific enthalpy of the externally supplied fuel and the ejector return flow rate and specific enthalpy. A heat balance equation is established, which satisfies that the dynamic power loss is equal to the total mass flow rate at the pump inlet multiplied by the difference between the specific enthalpy at the pump outlet and the mixing specific enthalpy. Set an initial value for the external fuel mass flow rate and update it iteratively. When the iteration converges and the pump outlet temperature rise does not exceed the dynamic allowable temperature rise, the pump anti-vaporization conditions are met, and the pump outlet fuel viscosity is not lower than the minimum allowable viscosity, output the converged external fuel mass flow rate and multiply it by a preset safety factor to obtain the minimum continuous heat flow rate.

[0016] In a second aspect, the present invention provides a device for calculating the minimum continuous heat flow of a fuel centrifugal pump, comprising: The parameter acquisition module is used to acquire pressure parameters, flow parameters, temperature parameters, and fuel physical property data during the operation of the fuel centrifugal pump system. The characteristic number calculation module is used to calculate the working pressure ratio of the ejector based on the pressure parameters, and to determine the dynamic physical property characteristic number of the fuel based on the fuel physical property data. The dynamic physical property characteristic number includes at least the viscosity characteristic number and the vaporization margin characteristic number. The ejector coefficient determination module is used to determine the dynamic ejector coefficient of the ejector based on the working pressure ratio and dynamic physical property characteristic number, and to calculate the ejector return flow rate based on the dynamic ejector coefficient; The allowable temperature rise determination module is used to determine the dynamic allowable temperature rise, which is jointly limited by vaporization constraints, viscosity constraints, and structural constraints, based on the relationship between fuel saturated vapor pressure and temperature and the local minimum pressure inside the pump. The power loss correction module is used to correct the power loss of the fuel centrifugal pump based on the viscosity-temperature characteristics in the fuel property data to obtain the dynamic power loss. The heat flow calculation module is used to establish the specific enthalpy heat balance relationship based on the ejector return flow rate, dynamic power loss and specific heat capacity characteristics in the fuel physical property data, and combined with the dynamic allowable temperature rise, to iteratively solve for the minimum continuous heat flow of the fuel centrifugal pump.

[0017] Thirdly, the present invention provides an electronic device including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to execute the above-described method for calculating the minimum continuous heat flow of a fuel centrifugal pump.

[0018] Fourthly, the present invention provides a readable storage medium storing a computer program, the computer program including program code for controlling a process to execute the process, the process including the calculation method for the minimum continuous heat flow of the fuel centrifugal pump described above.

[0019] The main contributions and innovations of this invention are as follows: 1. This invention calculates the vaporization limit temperature by back-calculating the fuel saturated vapor pressure curve and the lowest local pressure within the pump. It then combines this with the minimum allowable temperature rise based on structural and viscosity limitations, taking this as the final allowable temperature rise. This allows the thermal balance calculation to be actively constrained by the vaporization margin. Compared to existing technologies that use a fixed safety temperature rise, this invention effectively prevents localized vaporization and cavitation under low flow conditions, significantly improving the reliability of continuous operation of the fuel centrifugal pump.

[0020] 2. This invention constructs the dynamic ejector coefficient as a multivariate coupled function of the working pressure ratio, viscosity correction characteristic number, and vaporization margin characteristic number, rather than characterizing it only by a single dimension such as pressure ratio or flow rate ratio as in the prior art. By introducing corrections for the entrainment capacity due to fuel viscosity-temperature changes and for the decrease in backflow stability near the vaporization boundary, the calculation of the ejector backflow flow rate can be adapted to cold-state high viscosity, high-temperature low viscosity, and vaporization critical conditions, avoiding the underestimation of the minimum continuous heat flux caused by ejector coefficient deviation.

[0021] 3. This invention uses the enthalpy integral instead of the constant specific heat capacity for heat balance calculations, incorporating the nonlinear change in fuel specific heat capacity with temperature into the heat balance equation, and determining the pump inlet state based on the mixing enthalpy of fresh fuel and ejector return fuel. Under conditions of large temperature rise or significant changes in physical properties, this correction can effectively eliminate the calculation bias caused by the constant specific heat capacity assumption, making the heat balance results closer to the actual physical process.

[0022] 4. This invention calculates power loss based on the correction relationship between fuel viscosity and pump efficiency, ensuring that the heat source term changes in real time with fuel temperature. Under low-temperature, high-viscosity conditions, power loss increases due to reduced efficiency, leading to a more conservative calculation result; under high-temperature, low-viscosity conditions, power loss decreases as efficiency recovers, avoiding excessive conservatism. Compared to existing technologies that use a fixed efficiency, this invention can reasonably assess the heat generation within the pump across the entire temperature range.

[0023] 5. The calculation results of this invention can be directly used for setting low flow protection threshold, controlling bypass valve opening, determining fuel pump thermal test boundaries, and designing fuel system matching. In engineering, it simultaneously takes into account heat dissipation, vaporization safety, and pump performance changes, and is applicable to various fuel media such as aviation kerosene, diesel, and gasoline.

[0024] Details of one or more embodiments of the present invention are set forth in the following drawings and description, so that other features, objects and advantages of the invention will be more readily understood. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart of a method for calculating the minimum continuous heat flow of a fuel centrifugal pump according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0026] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with one or more embodiments of this specification. Rather, they are merely examples of apparatuses and methods consistent with some aspects of one or more embodiments of this specification as detailed in the appended claims.

[0027] It should be noted that the steps of the corresponding methods are not necessarily performed in the order shown and described in this specification in other embodiments. In some other embodiments, the methods may include more or fewer steps than described in this specification. Furthermore, a single step described in this specification may be broken down into multiple steps in other embodiments; and multiple steps described in this specification may be combined into a single step in other embodiments.

[0028] This invention introduces fuel vaporization margin constraints, viscosity-temperature characteristics correction, and specific enthalpy heat balance into the calculation of centrifugal pump heat flow. It belongs to the engineering calculation method in the field of fuel pump thermal management technology. Its purpose is to solve the practical engineering problems of fuel centrifugal pumps under low flow conditions, namely local vaporization, cavitation, and pump body overheating, rather than purely mathematical problems.

[0029] Example 1 This embodiment provides a method for calculating the minimum continuous heat flow of a fuel centrifugal pump, considering fuel vaporization margin and viscosity-temperature coupling correction. It is applicable to fuel centrifugal pump systems with ejectors. The system includes a fuel centrifugal pump, an ejector, a fuel tank or upstream fuel supply line, a return line, a pressure sensor, a temperature sensor, a flow sensor, and a controller. A portion of the high-pressure fuel at the pump outlet enters the ejector as the active flow. The ejector entrains low-pressure fuel, forming a mixed return flow. The heat generated by the pump under low-flow conditions is carried away by the fuel flowing through the pump body. This method, when calculating the minimum continuous heat flow, not only calculates the ejector return flow but also dynamically corrects for allowable temperature rise and power loss based on fuel property curves and the pump's vaporization margin.

[0030] like Figure 1 As shown, the calculation method in this embodiment includes the following steps S1 to S7: Step S1: Obtain basic operating parameters and fuel physical property parameters.

[0031] S11, Obtain pressure parameters. Pressure parameters must include at least the fuel centrifugal pump inlet pressure. Export pressure Ejector active inlet pressure Ejector jet inlet pressure Ejector outlet mixed flow pressure The system also collects pressure drop parameters from the suction line, impeller inlet, or pressure measurement points in the low-pressure zone of the pump, used to estimate the local minimum pressure within the pump. All pressure parameters are acquired using pressure sensors installed on the system pipelines, with the same pressure reference used during acquisition.

[0032] S12, Obtain flow parameters. Flow parameters must include at least the ejector active flow mass flow rate. Mass flow rate of fuel supplied from outside the system or added to the fuel tank Total mass flow rate at pump inlet Ejector reflux mass flow rate Among them, active flow mass flow rate It can be measured directly by a flow meter, or determined by the difference between the total flow rate at the pump outlet and the external supply flow rate.

[0033] S13, Obtain temperature parameters. Temperature parameters must include at least the temperature of the fuel tank or upstream fresh fuel. Pump inlet mixing temperature Pump outlet temperature Injector recirculation fuel temperature and ejector active flow temperature Temperature parameters are collected by temperature sensors installed at the oil tank outlet, pump inlet, pump outlet, and ejector piping.

[0034] S14, obtain the fuel property function. Establish or retrieve the fuel density function for the fuel grade used. Specific heat capacity at constant pressure saturated vapor pressure Dynamic viscosity or kinematic viscosity Functions that change with temperature, lookup table data, or piecewise interpolation data. In this embodiment, the physical property functions can be in the following forms: Density function:

[0035] in Reference temperature The density value below, is the coefficient of volume expansion.

[0036] Specific heat capacity function at constant pressure:

[0037] in , , The fitting coefficient is determined from fuel property manuals or calibration tests.

[0038] Kinematic viscosity function:

[0039] in , , These are the fitting coefficients for the Vogel-Fulcher equation.

[0040] Saturated vapor pressure function:

[0041] in , , These are the fitting coefficients for the Antoine equation.

[0042] The aforementioned coefficients can be determined from fuel property manuals, fuel grade test data, or specialized calibration tests to cover the temperature, pressure, and batch range of fuels that may occur in actual operation. For aviation kerosene, diesel, gasoline, or other fuels, corresponding property curves can be established separately, or different parameter groups can be called according to the fuel grade.

[0043] S15, Obtain pump performance and correction data. The pump performance and correction data must include at least the pump speed. Input power Reference efficiency Head or pressure rise curve Efficiency-viscosity correction factor NPSH requirements Or local minimum pressure model Among them, the efficiency-viscosity correction factor and local minimum pressure model It can be determined through pump performance calibration tests under different fuel temperatures or equivalent viscosity media.

[0044] S16, Obtain the safety threshold. The safety threshold includes at least the allowable temperature rise of the structure or materials. Anti-vaporization pressure margin Minimum permissible viscosity Temperature safety margin and the final output flow safety factor Among them, the safety factor A value greater than 1 is used to add a safety margin based on the calculated minimum continuous heat flow. The specific value is determined based on the system safety level, control strategy, and engineering experience.

[0045] Step S2: Calculate the ejector working pressure ratio and the dynamic physical property characteristics of the fuel.

[0046] First, the ejector working pressure ratio is calculated based on the pressure parameters obtained in step S11. :

[0047] in The active flow inlet pressure of the ejector. The ejector outlet mixing flow pressure, The ejector jet inlet pressure is the same pressure reference for all pressures.

[0048] Next, the dynamic physical property characteristics of the fuel, including viscosity characteristics, are calculated. and vaporization margin characteristic number .

[0049] Viscosity characteristic number Defined as the ratio of the fuel kinematic viscosity at the current mixing temperature to the reference kinematic viscosity:

[0050] in The temperature of the mixed fuel at the ejector or pump inlet. This represents the kinematic viscosity of the fuel at the reference calibration temperature. Viscosity characteristic number. It characterizes the degree of deviation between the fuel viscosity at the current mixing temperature and the reference viscosity, reflecting the impact of viscosity changes on the ejector entrainment capacity and the flow state within the pump.

[0051] vaporization margin characteristic number Defined as the ratio of actual vaporization margin to reference vaporization margin:

[0052] in This refers to the lowest local pressure within the pump or in the ejector return path. This represents the saturated vapor pressure corresponding to the current temperature of the mixed fuel. This is the preset anti-vaporization safety pressure margin. The reference pressure difference. The smaller the value, the closer the fuel is to the vaporization boundary, and the lower the ejector entrainment stability and the safety margin for continuous operation within the pump.

[0053] Step S3: Determine the dynamic ejection coefficient based on the working pressure ratio and dynamic physical property characteristic number.

[0054] Under baseline operating conditions, the actual ejector mass flow rate is used. With active flow quality flow The ratio determines the reference ejection coefficient. This method constructs the ejection coefficient as a coupling function of the working pressure ratio and the dynamic physical property characteristic number.

[0055] As one implementation method, during the fuel calibration test, the ejector active flow pressure, ejector flow pressure, mixed flow pressure, fuel temperature, and backflow back pressure were varied, and multiple sets of data were recorded. The data is fitted using multivariate polynomials, piecewise interpolation, lookup tables, or radial basis functions to obtain the dynamic ejection coefficient function. For example, it can be expressed in the following multivariate polynomial form:

[0056] in to The fitting coefficient is determined from the calibration test data.

[0057] As another implementation method, if the calibration data is limited, it can be established first based on the pressure ratio. Then, a multiplicative correction term is established using the fuel viscosity curve and vaporization margin curve:

[0058] in As the reference ejection coefficient, This is the pressure ratio correction function. , To correct the fitting coefficients for viscosity, This is the vaporization margin correction function. It decreases as the vaporization margin decreases, reflecting the phenomenon of reduced ejector efficiency when liquid fuel recirculation approaches vaporization.

[0059] To ensure the safety of the project, Set upper and lower limits. When When the vaporization margin is below the preset threshold, for Perform a rate reduction correction or trigger a protection action.

[0060] After determining the dynamic ejector coefficient, the ejector return mass flow rate is calculated using the following formula:

[0061] Step S4: Calculate the minimum local pressure and dynamic allowable temperature rise inside the pump.

[0062] Since whether fuel vaporization occurs depends on the relationship between local pressure and saturated vapor pressure at the current temperature, this method first determines the local minimum pressure in the pump or ejector return path before performing heat balance calculations. . It can be measured directly by a pressure sensor, or it can be obtained by subtracting the pressure drop in the suction line, the pressure drop at the impeller inlet, and the local acceleration pressure drop from the pump inlet pressure:

[0063] in To reduce the pressure drop in the suction line, The pressure drop at the impeller inlet is a function of the total mass flow rate at the pump inlet, fuel viscosity, and temperature.

[0064] The vaporization limiting temperature can be solved by using the inverse function of the fuel saturated vapor pressure function or through numerical iteration. To satisfy:

[0065] when When the saturated vapor pressure is less than or equal to the current temperature, the controller determines that the current operating condition does not meet the conditions for continuous safe operation and increases the minimum continuous heat flow to the protection flow or issues a vaporization risk alarm.

[0066] When a safety margin is available, the allowable temperature rise due to vaporization constraint is:

[0067] in The mixing temperature at the pump inlet. This is a safety margin for temperature.

[0068] Furthermore, based on the minimum permissible viscosity Inverse viscosity limiting temperature To satisfy The viscosity limit allows for a temperature rise of:

[0069] The final allowable temperature rise is the minimum value among the structural allowable temperature rise, the vaporization constraint allowable temperature rise, and the viscosity constraint allowable temperature rise:

[0070] Therefore, the allowable temperature rise is no longer a fixed constant, but a dynamic value that changes in real time with the fuel grade, inlet temperature, local pressure, viscosity, and vaporization margin.

[0071] Step S5: Correct pump power loss based on viscosity-temperature characteristics.

[0072] Fuel temperature variations alter pump efficiency and line resistance; therefore, this method expresses pump power loss as a viscosity-dependent function. Specifically, the average viscosity within the pump inlet to outlet temperature range is first determined. Then, based on the average viscosity, look up the efficiency minus the viscosity correction factor. Combined with benchmark efficiency The corrected pump efficiency is obtained:

[0073] Pump power loss is calculated using the following formula:

[0074] Under low temperature and high viscosity fuel conditions This can improve the efficiency after correction. Reduced, thus leading to Increase; under high-temperature, low-viscosity operating conditions, although reduced viscosity may decrease some flow losses, leakage losses, vaporization risk, and lubrication margin will change accordingly. The above correction aligns the heat source term with the actual state of the fuel, avoiding errors caused by using a fixed efficiency.

[0075] As another implementation method, the pump power loss can also be calculated using the following formula:

[0076] in This is the pump volumetric flow rate. For average density, It is the acceleration due to gravity. To account for the head after viscosity correction.

[0077] Step S6: Establish the fuel specific enthalpy mixing and heat balance equation.

[0078] Calculate the ejector return mass flow rate based on the dynamic ejector coefficient:

[0079] The total mass flow rate at the pump inlet is ,in This represents the minimum continuous thermal mass flow rate to be replenished from the tank or upstream system. To ensure compatibility with traditional volumetric flow rate expressions, it can ultimately be converted to... .

[0080] The specific enthalpy of fuel is obtained by integrating the specific heat capacity with temperature:

[0081] When the specific heat capacity function is adopted At that time, the specific enthalpy function can be expanded as:

[0082] in It is an integration constant and can be eliminated in the difference calculation.

[0083] The specific enthalpy of the mixed fuel at the pump inlet meets the following requirements:

[0084] in For fresh fuel at temperature Enthalpy below For ejecting recirculated fuel at temperature The specific enthalpy is below that. If the pressure difference between the ejector recirculated fuel and the fresh fuel is large, throttling or mixing loss correction terms can also be considered.

[0085] The internal heat balance equation of the pump is:

[0086] And require to meet ,and .

[0087] Compared with conventional heat balance equations Unlike other fuels, this equation incorporates the specific heat of fuel under varying temperatures, density changes, and enthalpy of refluxing mixture, making it suitable for fuels operating under conditions of significant temperature rise or substantial changes in physical properties.

[0088] Step S7: Iteratively solve for the minimum continuous heat flow.

[0089] S71, setting the external fuel mass flow rate or volumetric flow rate The initial value is determined, and the pump inlet pressure is estimated based on the current flow rate. Export pressure Ejector active inlet pressure Jet inlet pressure Mixed flow pressure Inlet temperature outlet temperature and local minimum pressure .

[0090] S72, Calculate the working pressure ratio based on step S2. Viscosity characteristic number and vaporization margin characteristic number The dynamic ejection coefficient is obtained according to step S3. The ejector recirculation mass flow rate is obtained according to step S6. and the total mass flow rate at the pump inlet .

[0091] S73, calculate the dynamic allowable temperature rise based on step S4. Correct the pump power loss according to step S5. The new external fuel mass flow rate is calculated based on the specific enthalpy heat balance equation in step S6. .

[0092] S74, determine new Compared to the previous round Check if the difference is less than the preset convergence threshold, and simultaneously determine if all three of the following conditions are met: Condition one: That is, the pump outlet temperature rise does not exceed the dynamic allowable temperature rise; Condition two: This means that no vaporization occurs inside the pump; Condition three: That is, the viscosity of the fuel at the pump outlet shall not be lower than the minimum allowable viscosity.

[0093] If any condition is not met, then increase. Alternatively, adjust the protection flow and return to step S71 to continue iteration. When the controller calculates in real time... Below the preset threshold Less than the structural allowable temperature rise or When the viscosity is below the minimum allowable viscosity, even if the energy balance calculation yields a lower flow rate, the larger flow rate corresponding to the vaporization or viscosity constraint should be used as the final minimum continuous heat flow rate.

[0094] S75, after iterative convergence, outputs the external fuel mass flow rate. and conversion of volumetric flow rate and multiplied by a safety factor The minimum continuous heat flow required by the control system is obtained as follows:

[0095] The results can be used for low flow alarms, bypass or return valve control, pump test boundary setting, and fuel system thermal safety design.

[0096] Further implementation methods and calibration requirements: Fuel property calibration should cover the temperature, pressure, and batch range of fuels that may occur during actual operation. For aviation kerosene, diesel, gasoline, or other fuels, corresponding property curves can be established separately, or different parameter groups can be called according to fuel grade.

[0097] Ejector calibration should not only record the relationship between pressure ratio and ejector coefficient, but also record the ejector backflow stability under different fuel temperatures, viscosities, and back pressures to establish... Or a corresponding mapping table.

[0098] Pump performance calibration can be performed by measuring the efficiency correction factor under different fuel temperatures or equivalent viscosity media. Pressure drop model and local minimum pressure model are used to simultaneously correct for heat source terms and vaporization constraints in the calculation.

[0099] When the controller calculates in real time... Below the preset threshold Less than the structural allowable temperature rise or When the viscosity is below the minimum allowable viscosity, even if the energy balance calculation yields a lower flow rate, the larger flow rate corresponding to the vaporization or viscosity constraint should be used as the final minimum continuous heat flow rate.

[0100] Example 2 This embodiment provides a calculation device for the minimum continuous heat flow of a fuel centrifugal pump, used to execute the calculation method of Embodiment 1. The device includes: The parameter acquisition module is used to acquire pressure, flow, and temperature parameters, as well as fuel property data, during the operation of the fuel centrifugal pump system. Specifically, this module connects to pressure, temperature, and flow sensors installed on various pipelines in the system via a communication interface to collect operational data in real time and retrieve the property functions or lookup data of the fuel used from a fuel property database or pre-stored parameter tables.

[0101] The feature number calculation module, connected to the parameter acquisition module, is used to calculate the working pressure ratio of the ejector based on the pressure parameters. Based on the fuel physical property data, the dynamic physical property characteristic number of the fuel is determined, and the dynamic physical property characteristic number includes at least the viscosity characteristic number. and vaporization margin characteristic number .

[0102] The ejector coefficient determination module, connected to the characteristic number calculation module, is used to determine the dynamic ejector coefficient of the ejector based on the working pressure ratio and dynamic physical property characteristic numbers. It calculates the ejector return flow rate based on the dynamic ejector coefficient. This module internally stores pre-calibrated multivariate coupling correction functions, interpolation models, or calibration mapping tables, and performs derating correction or sends a protection signal to the controller when the vaporization margin characteristic number is lower than a preset threshold.

[0103] The permissible temperature rise determination module, connected to the parameter acquisition module, is used to determine the dynamically permissible temperature rise, which is constrained by vaporization, viscosity, and structural constraints, based on the relationship between fuel saturated vapor pressure and temperature, and the local minimum pressure within the pump. This module internally stores the fuel saturated vapor pressure function. and viscosity function It can perform the calculation of vaporization limit temperature and viscosity limit temperature, and output the minimum value of the triple constraints.

[0104] The power loss correction module, connected to the parameter acquisition module, corrects the power loss of the fuel centrifugal pump based on the viscosity-temperature characteristics in the fuel property data, thus obtaining the dynamic power loss. This module internally stores pump efficiency-viscosity correction coefficients. The data or function can correct the pump efficiency and calculate the power loss based on the average viscosity in the pump inlet to outlet range.

[0105] The heat flow calculation module is connected to the ejector coefficient determination module, the allowable temperature rise determination module, and the power loss correction module, respectively. It is used to establish the specific enthalpy heat balance relationship based on the ejector return flow rate, dynamic power loss, and specific heat capacity characteristics in the fuel physical property data, and combined with the dynamic allowable temperature rise, iteratively solves to obtain the minimum continuous heat flow of the fuel centrifugal pump.

[0106] The data flow between the above modules is consistent with the logical order of steps S1 to S7 in Example 1, forming a complete closed-loop calculation process.

[0107] Example 3 This embodiment also provides an electronic device, see reference. Figure 2 It includes a memory 402 and a processor 401, the memory 402 storing a computer program and the processor 401 being configured to run the computer program to perform the steps in any of the above method embodiments.

[0108] Specifically, the processor 401 may include a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of the present invention.

[0109] The memory 402 may include a mass storage device for data or instructions. For example, and not limitingly, the memory 402 may include a hard disk drive (HDD), a floppy disk drive, a solid-state drive (SSD), flash memory, an optical disk drive, a magneto-optical disk drive, magnetic tape, or a Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 402 may include removable or non-removable (or fixed) media. Where appropriate, the memory 402 may be internal or external to a data processing device. In a particular embodiment, the memory 402 is non-volatile memory. In a particular embodiment, the memory 402 includes read-only memory (ROM) and random access memory (RAM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable read-only memory (PROM), an erasable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), an electrically alterable read-only memory (EAROM), or flash memory, or a combination of two or more of these. Where appropriate, the RAM can be Static Random-Access Memory (SRAM) or Dynamic Random-Access Memory (DRAM). DRAM can be Fast Page Mode Dynamic Random Access Memory (FPMDRAM), Extended Data Out Dynamic Random Access Memory (EDODRAM), Synchronous Dynamic Random-Access Memory (SDRAM), etc.

[0110] The memory 402 can be used to store or cache various data files that need to be processed and / or communicated, as well as possible computer program instructions executed by the processor 401.

[0111] The processor 401 reads and executes computer program instructions stored in the memory 402 to implement any of the methods for calculating the minimum continuous heat flow of the fuel centrifugal pump in the above embodiments.

[0112] Optionally, the electronic device may further include a transmission device 403 and an input / output device 404, wherein the transmission device 403 is connected to the processor 401 and the input / output device 404 is connected to the processor 401.

[0113] The transmission device 403 can be used to receive or send data via a network. Specific examples of the network described above may include wired or wireless networks provided by the communication provider of the electronic device. In one example, the transmission device includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device 403 may be a Radio Frequency (RF) module used for wireless communication with the Internet.

[0114] Input / output device 404 is used for inputting or outputting information. It can be a speaker, microphone, monitor, or keyboard.

[0115] Example 4 This embodiment also provides a readable storage medium storing a computer program, the computer program including program code for controlling a process to execute the process, the process including a method for calculating the minimum continuous heat flow of a fuel centrifugal pump according to Embodiment 1.

[0116] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementations, and will not be repeated here.

[0117] Generally, various embodiments can be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects of the invention can be implemented in hardware, while others can be implemented by firmware or software executed by a controller, microprocessor, or other computing device, but the invention is not limited thereto. Although various aspects of the invention may be shown and described as block diagrams, flowcharts, or using some other graphical representation, it should be understood that, by way of non-limiting example, these blocks, apparatuses, systems, techniques, or methods described herein can be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0118] Embodiments of the present invention can be implemented by computer software, which may be executable by a data processor of a mobile device, such as a processor entity, or by hardware, or by a combination of software and hardware. Computer software or programs (also referred to as program products) including software routines, applets, and / or macros can be stored in any device-readable data storage medium, and they include program instructions for performing specific tasks. The computer program product may include one or more computer-executable components configured to perform the embodiments when the program is run. The one or more computer-executable components may be at least one piece of software code or a portion thereof. Additionally, it should be noted in this respect that, as Figure 1 Any box in the logical flow can represent a program step, or interconnected logic circuits, boxes and functions, or a combination of program steps and logic circuits, boxes and functions. Software can be stored on physical media such as memory chips or blocks of storage implemented within a processor, magnetic media such as hard disks or floppy disks, and optical media such as DVDs and their data variants, CDs, etc. The physical medium is a non-transient medium.

[0119] Those skilled in the art should understand that 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 have been 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.

[0120] The above embodiments are merely illustrative of several implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A method for calculating the minimum continuous heat flow of a fuel centrifugal pump, applicable to fuel centrifugal pump systems with ejectors, characterized in that, Includes the following steps: Acquire pressure, flow, temperature, and fuel properties data during the operation of the fuel centrifugal pump system; The working pressure ratio of the ejector is calculated based on the pressure parameters, and the dynamic physical property characteristics of the fuel are determined based on the fuel property data. The dynamic physical property characteristics include at least the viscosity characteristics and the vaporization margin characteristics. The dynamic ejection coefficient of the ejector is determined based on the working pressure ratio and the dynamic physical property characteristic number, and the ejection return flow rate is calculated based on the dynamic ejection coefficient. Based on the relationship between fuel saturated vapor pressure and temperature and the local minimum pressure inside the pump, the dynamic allowable temperature rise, which is jointly limited by vaporization constraints, viscosity constraints, and structural constraints, is determined. The power loss of the fuel centrifugal pump is corrected based on the viscosity-temperature characteristics in the fuel physical property data to obtain the dynamic power loss. Based on the ejector return flow rate, the dynamic power loss, and the specific heat capacity characteristics in the fuel physical property data, a specific enthalpy heat balance relationship is established, and combined with the dynamic allowable temperature rise, the minimum continuous heat flow rate of the fuel centrifugal pump is obtained by iterative solution.

2. The calculation method as described in claim 1, characterized in that, The viscosity characteristic number is determined based on the ratio of the fuel kinematic viscosity at the current mixing temperature to the reference kinematic viscosity; the vaporization margin characteristic number is determined based on the ratio of the difference between the local minimum pressure in the pump, the fuel saturated vapor pressure at the current mixing temperature, and the preset safety pressure margin to the reference pressure difference.

3. The calculation method as described in claim 1, characterized in that, The dynamic ejection coefficient of the ejector is determined based on the working pressure ratio and the dynamic physical property characteristic number, including: The working pressure ratio, viscosity characteristic number, and vaporization margin characteristic number are input into a pre-constructed multivariate coupling correction function, interpolation model, or calibration mapping table to calculate the dynamic ejection coefficient; or The dynamic ejection coefficient is obtained by multiplicatively correcting the reference ejection coefficient using pressure ratio correction term, viscosity correction term, and vaporization margin correction term. When the vaporization margin characteristic number is lower than the preset vaporization margin threshold, the dynamic ejection coefficient is derated or a protection action is triggered.

4. The calculation method as described in claim 1, characterized in that, The dynamic allowable temperature rise, constrained by vaporization, viscosity, and structural limitations, is determined based on the relationship between fuel saturated vapor pressure and temperature, and the local minimum pressure within the pump. This includes: The local minimum pressure inside the pump can be calculated based on the inlet pressure of the fuel centrifugal pump, the pressure drop in the suction line and the pressure drop at the impeller inlet, or the local minimum pressure inside the pump can be directly obtained through a pressure sensor. Based on the relationship between the saturated vapor pressure and temperature and the preset safety pressure margin, the vaporization limit temperature at which vaporization does not occur is calculated, and the allowable temperature rise for vaporization constraint is calculated from the vaporization limit temperature. The viscosity limit for permissible temperature rise is calculated by back-calculating the minimum permissible viscosity and the viscosity-temperature characteristics of the fuel. The minimum value among the vaporization constraint allowable temperature rise, the preset structure allowable temperature rise, and the viscosity limit allowable temperature rise is determined as the dynamic allowable temperature rise.

5. The calculation method as described in claim 4, characterized in that, When the minimum local pressure in the pump minus the preset safety pressure margin is less than or equal to the saturated vapor pressure corresponding to the current temperature, it is determined that the current operating condition does not meet the conditions for continuous safe operation, and the minimum continuous heat flow is increased to the protection flow or a vaporization risk alarm is issued.

6. The calculation method as described in claim 1, characterized in that, The power loss of the fuel centrifugal pump is corrected based on the viscosity-temperature characteristics in the fuel property data to obtain the dynamic power loss, including: Determine the average viscosity within the temperature range from the inlet to the outlet of the fuel centrifugal pump. The pump reference efficiency is corrected based on the average viscosity utilization efficiency viscosity correction coefficient to obtain the corrected efficiency; The dynamic power loss is calculated based on the pump input power and the corrected efficiency.

7. The calculation method as described in claim 1, characterized in that, Based on the ejector return flow rate, the dynamic power loss, and the specific heat capacity characteristics in the fuel physical property data, a specific enthalpy heat balance relationship is established. Combined with the dynamic allowable temperature rise, the minimum continuous heat flow rate of the fuel centrifugal pump is iteratively solved, including: The specific heat capacity at constant pressure in the fuel physical property data is integrated over the temperature range to obtain the fuel specific enthalpy; The mixing enthalpy at the pump inlet is calculated based on the external fuel mass flow rate and its specific enthalpy, and the ejector return flow rate and its specific enthalpy. A heat balance equation is established, which satisfies that the dynamic power loss is equal to the total mass flow rate at the pump inlet multiplied by the difference between the pump outlet specific enthalpy and the mixing specific enthalpy. An initial value for the external fuel mass flow rate is set and iteratively updated. When the iteration converges and the pump outlet temperature rise does not exceed the dynamic allowable temperature rise, the pump anti-vaporization condition is met, and the pump outlet fuel viscosity is not lower than the minimum allowable viscosity, the converged external fuel mass flow rate is output and multiplied by a preset safety factor to obtain the minimum continuous heat flow rate.

8. A device for calculating the minimum continuous heat flow of a fuel centrifugal pump, characterized in that, include: The parameter acquisition module is used to acquire pressure parameters, flow parameters, temperature parameters, and fuel physical property data during the operation of the fuel centrifugal pump system. The feature number calculation module is used to calculate the working pressure ratio of the ejector based on the pressure parameters, and to determine the dynamic physical property feature number of the fuel based on the fuel physical property data. The dynamic physical property feature number includes at least the viscosity feature number and the vaporization margin feature number. The ejector coefficient determination module is used to determine the dynamic ejector coefficient of the ejector based on the working pressure ratio and the dynamic physical property characteristic number, and to calculate the ejector return flow rate based on the dynamic ejector coefficient; The allowable temperature rise determination module is used to determine the dynamic allowable temperature rise, which is jointly limited by vaporization constraints, viscosity constraints, and structural constraints, based on the relationship between fuel saturated vapor pressure and temperature and the local minimum pressure inside the pump. A power loss correction module is used to correct the power loss of the fuel centrifugal pump based on the viscosity-temperature characteristics in the fuel physical property data to obtain dynamic power loss. The heat flow calculation module is used to establish a specific enthalpy heat balance relationship based on the ejector return flow rate, the dynamic power loss, and the specific heat capacity characteristics in the fuel physical property data, and to iteratively solve for the minimum continuous heat flow of the fuel centrifugal pump in combination with the dynamic allowable temperature rise.

9. An electronic device comprising a memory and a processor, characterized in that, The memory stores a computer program, and the processor is configured to run the computer program to perform the calculation method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, the computer program including program code for controlling a process to execute the process, the process including the calculation method according to any one of claims 1 to 7.

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