Engine starting throttling back calculation method based on test data

Abstract

The invention belongs to the field of ground and high-altitude starting performance simulation research, and particularly relates to an engine starting throttling back calculation method based on test data, starting throttling back calculation is carried out based on a power extraction method, and the combustion efficiency in the starting process is reversely evaluated according to the oil supply amount in the starting process, the rotor acceleration rate and starter characteristics. On the basis of the similarity principle, a conversion torque scaling coefficient calculation method is provided, conversion between the efficiency characteristic and the torque characteristic is completed, and the effectiveness of the method is verified. A pre-ignition starting performance calculation model is further established, starting performance simulation from the zero rotating speed to the slow rotating speed is achieved, and the simulation model is verified based on complete machine test data. A conversion torque scaling coefficient calculation method is provided, equivalent replacement of the efficiency characteristic and the torque characteristic is achieved, and the precision of the torque characteristic applied to engine whole machine calculation is improved.

Description

Technical Field

[0001] The present application belongs to the field of ground and high-altitude starting performance simulation research, and in particular relates to an engine starting throttling back-calculation method based on test data. Background Art

[0002] The simulation research of aircraft engine ground and high altitude starting performance is the focus of engine modeling and simulation technology. The simulation research of aircraft engine ground and high altitude starting performance includes numerical simulation of engine starting process.

[0003] The current numerical simulation of the engine starting process has the following disadvantages: 1) There are already a large number of methods for numerical simulation of the engine starting process, but the simulation accuracy is very low, the calculation convergence is poor, and there are great limitations in engineering practice application; 2) The existing start-up model correction does not take into account the impact of start-up combustion efficiency. In the low speed range, the combustion efficiency interpolated from the general combustion chamber characteristics is relatively high and the speed does not change much, which is obviously not in line with the actual situation. During the start-up of the turbine engine, the air inlet of the combustion chamber is uneven at low speed, and the oil-gas mixing is poor; at the same time, the combustion chamber is in a cold state with low pressure, which has a greater impact on combustion and low combustion efficiency.

[0004] Therefore, how to improve the calculation accuracy of numerical simulation of engine starting process is a problem that needs to be solved. Summary of the invention

[0005] The purpose of this application is to provide an engine start throttle back calculation method based on test data to solve the current problems of low numerical simulation accuracy and poor calculation convergence of the engine start process.

[0006] The technical solution of the present application is: a method for back-calculating engine start throttling based on test data, comprising: The torque method is used to convert the efficiency characteristics of the rotating parts into torque characteristics, and the converted torque characteristics are extended to the low speed area through similarity theory to obtain an accurate conversion torque scaling coefficient; Based on the test data, the starter speed-power characteristics, the rotor acceleration rate characteristics during the starting process and the fuel flow rate data during the starting process are obtained; based on the power extraction method and the conversion torque scaling coefficient, the fuel quantity control equation and the variable combustion efficiency are added to the steady-state balance equation group to obtain the rotor acceleration rate back-calculation model. The rotor acceleration rate back-calculation model reversely evaluates the combustion efficiency of the engine during the starting process through the reverse evaluation method of the starting combustion efficiency, and evaluates whether the combustion efficiency of the engine during the starting process can be throttled to the ignition speed. If so, proceed to the next step; and the fuel flow is added to construct the engine starting common working equation group; Establish an engine starting performance calculation model, and obtain the parameters of each component at the minimum speed point through the engine starting common working equation group, including compressor work, turbine work and total temperature before the turbine. According to the current starter power, an approximate calculation method is used to perform an approximate calculation of the starting process before ignition. The combustion efficiency of the engine during the starting process obtained by evaluation is substituted into the engine starting performance calculation model for simulation.

[0007] Preferably, the step of obtaining the converted torque scaling coefficient comprises: Obtain a characteristic diagram in an engine simulation program, set an efficiency characteristic scaling factor to scale the characteristic curve in the characteristic diagram, and obtain a torque characteristic; By specific heat Get the ideal unit work and construct the conversion torque proportional coefficient through the ideal unit work , the ideal unit work is solved by using the real pressure ratio coupled from the non-design point for the torque characteristics, and combined with the conversion torque proportional coefficient Get accurate torque scaling factor .

[0008] Preferably, the specific heat The formula is: ; The conversion torque proportionality factor for: ; The converted torque scaling factor The formula is: ; In the formula, is the mass flow rate, N is the rotation speed, is the relative physical conversion speed, C p is the specific heat of gas at constant pressure, is the temperature, is the compressor pressure ratio, γ is the specific heat ratio, For efficiency; is the temperature coefficient, specifically the ratio of the inlet temperature to the standard atmospheric temperature; π is the pressure ratio; To convert the torque design value, To convert the torque characteristic diagram value, Δ H ideal,map is the ideal unit power characteristic diagram value; ΔH ideal,des is the ideal unit work design value, ΔH ideal,offdes is the non-design point parameter after ideal unit power coupling.

[0009] Preferably, the starter speed-power characteristic and the rotor acceleration rate characteristic during the starting process are obtained specifically as follows: The starter torque is obtained by interpolating the high-pressure shaft speed, and then the starter transmission power is obtained. The starter speed-power characteristics and the rotor acceleration rate characteristics during the starting process are sorted out.

[0010] Preferably, the method for obtaining the fuel flow rate during the starting process is: The test bench uses a Coriolis mass flowmeter and a gear flowmeter in series to measure the fuel flow. At the same time, the measurement results of the Coriolis mass flowmeter are used to eliminate the bad points in the output results of the gear flowmeter that suddenly drop due to the influence of bubbles in the fuel pipeline, and the fuel flow during the starting process is obtained.

[0011] Preferably, the reverse evaluation method for starting combustion efficiency is specifically: constructing a group of engine starting common working equations to perform a reverse evaluation on the combustion efficiency.

[0012] Preferably, the engine starting common working equation group is: ; ; ; ; ; In the formula, The power consumption of the compressor is is the turbine output work, The power consumption is due to the resistance during the starting process. is the high pressure shaft acceleration power, is the starter power, W a3 is the combustion chamber inlet air flow rate, W fb is the fuel flow rate, W g4 is the combustion chamber outlet gas flow rate, W g9 is the engine outlet gas flow rate, n OB is the engine speed control variable, n is the relative physical speed, W fb_OB The fuel flow control amount.

[0013] Preferably, the approximate calculation of the pre-ignition starting process is specifically: Establish an engine starting performance calculation model to obtain the relationship between starter power and relative physical speed; The starter power is selected to have a cubic relationship with the ignition speed, and the relative physical speed is selected to have a linear relationship with the ignition speed; the working point of the ignition speed is selected as the reference point, and the engine compressor work, turbine work and total temperature before the turbine are obtained by interpolating the speed between zero speed and ignition speed, and the starter power at the current time t is obtained according to the starter characteristics; At time t+Δt, the relative physical speed n at the previous time t is used as the initial value at the current time, the starter power is calculated repeatedly, and then the rotor acceleration rate is calculated according to the rotor dynamics equation. dn / dt , then according to the formula n t+Δt =n t + dn / dt , regain n 1 t+Δt Repeat this process until the n Calculated times n n t+Δt Convergence, calculation ends, and the speed at the current moment is obtained n t+Δt ; Determine the current speed n t+Δt Whether the ignition speed is reached, if not, the speed calculation is performed again at different times until the speed reaches the ignition speed, completing the starting performance calculation before ignition.

[0014] The engine start throttle back calculation method based on test data of the present application has the following advantages: 1. A method for calculating the conversion torque scaling coefficient is proposed to achieve equivalent replacement of efficiency characteristics and torque characteristics, and improve the accuracy of torque characteristics applied to engine calculations; 2. It can make full use of the test data of the engine starting process to realize the approximate simulation of the starting process. With the fuel flow, rotor acceleration rate and starter characteristics as input, the combustion efficiency of the starting process can be calculated in reverse, thus improving the accuracy of the starting simulation; 3. Fully consider the constraints and matching conditions between the various components and systems of the engine. The evaluation results meet the whole machine matching constraints such as flow balance, power balance, static pressure balance and speed equality, making the combustion efficiency evaluation results more reliable and objective. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solution provided by the present application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0016] Figure 1This is a schematic diagram of the overall process of this application; Figure 2 The starter characteristic diagram for this application; Figure 3 This is the rotor acceleration rate characteristic diagram during the starting process of this application. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] An engine starting throttling back-calculation method based on test data reversely evaluates the combustion efficiency during the starting process according to the fuel supply, rotor acceleration rate and starter characteristics during the starting process.

[0019] like Figure 1 , including the following steps: Step S100, low speed region characteristic curve expansion: using the torque method to convert the efficiency characteristics of the rotating component into torque characteristics, and expanding the converted torque characteristics to the low speed region through similarity theory to obtain an accurate conversion torque scaling coefficient; The steps of converting the torque scaling factor include: Step S110, obtain the characteristic diagram in the engine simulation program. The characteristic diagrams used in the engine simulation program are mostly general characteristics. The design point parameters in the characteristic diagram are quite different from the actual design point parameters of the engine. Therefore, it is necessary to set the efficiency characteristic scaling factor to scale the characteristic curve in the characteristic diagram to obtain the torque characteristic. for:

[0020] In the formula, For design efficiency; is the characteristic diagram value efficiency, obtained from the characteristic diagram.

[0021] Step S120, by determining the specific heat Get the ideal unit work and construct the conversion torque proportional coefficient through the ideal unit work , the ideal unit work is solved by using the real pressure ratio coupled from the non-design point for the torque characteristics, and combined with the conversion torque proportional coefficient Get accurate torque scaling factor .

[0022] When the efficiency characteristic is converted into a torque characteristic, the calculation method of the conversion torque scaling factor is no longer applicable. To find the proportional coefficient of the conversion torque, the detailed formula of the conversion torque must be derived first. The formula can be expressed as:

[0023] In the formula, is the mass flow rate, N is the rotation speed, is the relative physical conversion speed, C p is the specific heat of gas at constant pressure, is the temperature, is the compressor pressure ratio, γ is the specific heat ratio, For efficiency; is the temperature coefficient, specifically the ratio of the inlet temperature to the standard atmospheric temperature; π is the pressure ratio.

[0024] The converted torque is related to the converted flow, pressure ratio and efficiency. , π and There are corresponding scaling factors. Conversion flow scaling factor Scaling factor with compression ratio They are:

[0025]

[0026] In the formula, To convert the mass flow design value; To convert the mass flow characteristic diagram value; is the design value of pressure ratio, It is the pressure ratio characteristic diagram value.

[0027] Convert torque to is proportional to, and the scaling factor of the compression ratio is In addition, during the start-up process, efficiency should be avoided Therefore, the torque scaling factor cannot be calculated by reverse calculation through the flow scaling factor, pressure ratio scaling factor and efficiency scaling factor, nor can the torque scaling factor be simply calculated by proportionally converting the design point and the characteristic diagram parameters, which will lead to errors in the component work.

[0028] Through analysis, we can know that Refers to the ideal unit of work ΔH ideal The torque conversion coefficient constructed in this paper is as follows:

[0029] To convert the torque design value, To convert the torque characteristic diagram value, ΔH ideal,map is the ideal unit power characteristic diagram value; ΔH ideal,des It is the ideal unit work design value.

[0030] In non-design point calculations, the converted torque scaling factor is obtained The formula is as follows:

[0031] In the formula, ΔH ideal,offdes is the non-design point parameter after ideal unit power coupling.

[0032] This method is used to construct the conversion torque scaling factor, converting the ideal unit power ΔH ideal The relevant parameters are decoupled from the scaling factor.

[0033] Step S200, starting throttling back calculation: based on the test data, the starter speed-power characteristics, the rotor acceleration rate characteristics of the starting process and the fuel flow data of the starting process are obtained; based on the power extraction method and the converted torque scaling coefficient, the fuel quantity control equation and the variable combustion efficiency are added to the steady-state equilibrium equation group to obtain the rotor acceleration rate back calculation model. The rotor acceleration rate back calculation model reversely evaluates the combustion efficiency of the engine during the starting process through the starting combustion efficiency reverse evaluation method, and evaluates whether the combustion efficiency of the engine during the starting process can be throttled to the ignition speed. If so, proceed to the next step; and the fuel flow is added to construct the engine starting common working equation group; if not, return to step S100.

[0034] The engine used is a single-shaft turbojet. The models of each component level are not described in detail. The solution algorithm uses Newton's method iteration. Based on energy conservation and flow continuity, the common working equations of the steady-state model are:

[0035]

[0036]

[0037]

[0038] In the formula, The power consumption of the compressor is is the turbine output work, W a3 is the combustion chamber inlet air flow rate, W fb is the fuel flow rate, W g4is the combustion chamber outlet gas flow rate, W g9 is the engine outlet gas flow rate, n OB is the engine speed control variable, n is the relative physical speed.

[0039] Iteration variables are: compressor pressure ratio Z C , relative physical speed n , combustion chamber outlet temperature T 4. Turbine pressure drop ratio π T .

[0040] Preferably, the starter speed-power characteristics and the rotor acceleration rate characteristics during the starting process are obtained specifically as follows: The starter participates in the starting process by transmitting torque to the high-pressure shaft of the engine. The torque of the starter is linearly related to the speed. Therefore, the starter torque can be obtained by interpolating the high-pressure shaft speed, and then the starter transmission power can be obtained. The starter speed-power characteristics and the rotor acceleration rate characteristics of the starting process are sorted out. The relationship between the relative physical speed of the engine and the starter power is as follows: Figure 3 shown.

[0041] like Figure 2 , preferably, in the rotor acceleration rate back calculation model: The most important part of the throttling back calculation during the engine starting process is to determine the part that participates in the work / power consumption. The power balance equation during the starting process is:

[0042] in, The power consumption of the compressor is is the turbine output work, The power consumption is due to the resistance during the starting process. is the high pressure shaft acceleration power, is the starter power.

[0043] The power consumption of the starting process resistance is small and can be ignored, so the unknown quantity of power balance is the high-voltage shaft acceleration power. The calculation formula is:

[0044]

[0045] Where J is the moment of inertia, To convert torque, is the design speed value.

[0046] like Figure 3 , acceleration power and rotor acceleration rate The relationship is:

[0047] Therefore, it is necessary to calculate the rotor acceleration rate. Through the engine starting test, the relationship between the speed and time during the starting process can be obtained, and the rotor acceleration rate characteristics can be obtained through the test data.

[0048] Preferably, the method for obtaining the fuel flow rate during the starting process is: The test bench uses a Coriolis mass flowmeter and a gear flowmeter in series to measure the fuel flow. The fuel supply of the test data in this application is based on the measurement results of the gear flowmeter. At the same time, the measurement results of the Coriolis mass flowmeter are used to eliminate the bad points of the gear flowmeter output that suddenly drop due to the influence of bubbles in the fuel pipeline, and the fuel flow during the starting process is obtained.

[0049] Preferably, the reverse evaluation method of the starting combustion efficiency is as follows: during the starting process, the engine requires the combustion chamber to be able to ignite quickly and reliably and burn stably. Since the combustion efficiency in the general combustion chamber characteristic diagram does not decrease significantly with the speed, which does not conform to the actual situation, it is necessary to perform a reverse evaluation of the combustion efficiency.

[0050] The engine steady-state joint working equation group has four variables and four equilibrium equations. Through the test data, we have obtained the fuel flow and rotor acceleration rate during the starting process, and thus constructed the engine starting joint working equation group: ; ; ; ; ; In the formula, W fb_OB The fuel flow control amount.

[0051] The fitting formula of engine speed and fuel flow can be obtained through test data. Therefore, in the process of starting throttling back calculation, the current speed is interpolated to obtain W fb_OB Based on the steady-state equilibrium equations, the fuel flow rate in the test data is used as the control variable W fb_OB , bringing the number of balanced equations to 5, so a variable must be added to make the system of equations have a solution. Therefore, the variable combustion efficiency is added to the system of working equations.

[0052] Step S300, calculation of the starting process before ignition: establish an engine starting performance calculation model, and obtain the parameters of each component at the minimum speed point through the engine starting common working equation group, including compressor work, turbine work, total temperature before the turbine and other parameters, and use an approximate calculation method to perform an approximate calculation of the starting process before ignition based on the current starter power.

[0053] The speed range from zero to ignition is relatively small compared to the full speed range, and has little impact on the simulation calculation of the engine starting process. Therefore, an approximate calculation method is used in this range.

[0054] The parameters of each component at the minimum speed point, when the starter power is known, the relationship between the speed and time can be calculated. When using this method, in the process before ignition, the total temperature T4 at the combustion chamber outlet is equal to the total temperature at the combustion chamber inlet.

[0055] The specific steps are as follows: Step S310, establishing an engine starting performance calculation model to obtain a change relationship between starter power and relative physical speed; Step S320, select the cubic relationship between the starter power and the ignition speed, and the linear relationship between the relative physical speed and the ignition speed. Select the working point of the ignition speed as the reference point, interpolate the speed between zero speed and ignition speed, obtain the compressor work, turbine work and total temperature before the turbine of the engine, and obtain the starter power at the current time t according to the starter characteristics; Step S330, at time t+Δt, the relative physical speed n at the previous time t is used as the initial value at the current time, the starter power is repeatedly calculated, and then the rotor acceleration rate is calculated according to the rotor dynamics equation dn / dt , then according to the formula n t+Δt =n t +dn / dt , regain n 1 t+Δt Repeat this process until the n Calculated times n n t+Δt Convergence, calculation ends, and the speed at the current moment is obtained n t+Δt ; Step S340, determine the current speed n t+Δt Whether the ignition speed is reached, if not, repeat step S330 to calculate the speed at different times again until the speed reaches the ignition speed, at which time the pre-ignition starting performance calculation is completed.

[0056] Step S400, starting performance calculation: the combustion efficiency of the engine during the starting process obtained through evaluation is substituted into the engine starting performance calculation model for simulation.

[0057] The difference between the starting throttling back calculation and the starting performance calculation is that the throttling back calculation evaluates the combustion efficiency inversely based on the fuel flow, rotor acceleration rate and starting motor, while the starting performance calculation substitutes the evaluated combustion efficiency into the model for starting simulation. The solution methods of the nonlinear equation groups of the two are shown in the following table: Table 1 Solution table of engine nonlinear equations

[0058] In Table 1, WFB OB is the fuel flow control value, is the turbine pressure drop ratio; ETAB For combustion efficiency, Z c is the compressor pressure ratio.

[0059] In summary, this application has the following advantages: 1. A method for calculating the conversion torque scaling coefficient is proposed to achieve equivalent replacement of efficiency characteristics and torque characteristics, and improve the accuracy of torque characteristics applied to engine calculations; 2. It can make full use of the test data of the engine starting process to realize the approximate simulation of the starting process. With the fuel flow, rotor acceleration rate and starter characteristics as input, the combustion efficiency of the starting process can be calculated in reverse, thus improving the accuracy of the starting simulation; 3. Fully consider the constraints and matching conditions between the various components and systems of the engine. The evaluation results meet the whole machine matching constraints such as flow balance, power balance, static pressure balance and speed equality, making the combustion efficiency evaluation results more reliable and objective.

[0060] Finally, it should be noted that: the drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other; Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An engine start throttle back calculation method based on test data, characterized in that: include: The torque method is used to convert the efficiency characteristics of the rotating parts into torque characteristics, and the converted torque characteristics are extended to the low speed area through similarity theory to obtain an accurate conversion torque scaling coefficient; Based on the test data, the starter speed-power characteristics, the rotor acceleration rate characteristics during the starting process and the fuel flow rate data during the starting process are obtained; based on the power extraction method and the conversion torque scaling coefficient, the fuel quantity control equation and the variable combustion efficiency are added to the steady-state balance equation group to obtain the rotor acceleration rate back-calculation model. The rotor acceleration rate back-calculation model reversely evaluates the combustion efficiency of the engine during the starting process through the reverse evaluation method of the starting combustion efficiency, and evaluates whether the combustion efficiency of the engine during the starting process can be throttled to the ignition speed. If so, proceed to the next step; and the fuel flow is added to construct the engine starting common working equation group; Establish an engine starting performance calculation model, and obtain the parameters of each component at the minimum speed point through the engine starting common working equation group, including compressor work, turbine work and total temperature before the turbine. According to the current starter power, an approximate calculation method is used to perform an approximate calculation of the starting process before ignition. The combustion efficiency of the engine during the starting process obtained by evaluation is substituted into the engine starting performance calculation model for simulation.

2. The engine starting throttle back calculation method based on test data according to claim 1, characterized in that: The step of obtaining the torque scaling coefficient comprises: Obtain a characteristic diagram in an engine simulation program, set an efficiency characteristic scaling factor to scale the characteristic curve in the characteristic diagram, and obtain a torque characteristic; By specific heat Get the ideal unit work and construct the conversion torque proportional coefficient through the ideal unit work , the ideal unit work is solved by using the real pressure ratio coupled from the non-design point for the torque characteristics, and combined with the conversion torque proportional coefficient Get accurate torque scaling factor .

3. The engine starting throttle back calculation method based on test data as claimed in claim 2, characterized in that: The specific heat The formula is: ； The conversion torque proportionality factor for: ； The converted torque scaling factor The formula is: ； In the formula, is the mass flow rate, N is the rotation speed, is the relative physical conversion speed, C p is the specific heat of gas at constant pressure, is the temperature, is the compressor pressure ratio, γ is the specific heat ratio, For efficiency; is the temperature coefficient, specifically the ratio of the inlet temperature to the standard atmospheric temperature; π is the pressure ratio; To convert the torque design value, To convert the torque characteristic diagram value, Δ Hideal,map is the ideal unit power characteristic diagram value; Δ Hideal,des is the ideal unit work design value, Δ Hideal,offdes is the non-design point parameter after ideal unit power coupling.

4. The engine starting throttle back calculation method based on test data as claimed in claim 2, characterized in that: The starter speed-power characteristics and the rotor acceleration rate characteristics during the starting process are specifically obtained as follows: The starter torque is obtained by interpolating the high-pressure shaft speed, and then the starter transmission power is obtained. The starter speed-power characteristics and the rotor acceleration rate characteristics during the starting process are sorted out.

5. The engine starting throttle back calculation method based on test data as claimed in claim 1, characterized in that: The method for obtaining the fuel flow rate during the starting process is: The test bench uses a Coriolis mass flowmeter and a gear flowmeter in series to measure the fuel flow rate. At the same time, the measurement results of the Coriolis mass flowmeter are used to eliminate the bad points in the output results of the gear flowmeter that suddenly drop due to the influence of bubbles in the fuel pipeline, and the fuel flow rate during the starting process is obtained.

6. The engine starting throttle back calculation method based on test data as claimed in claim 1, characterized in that: The method for reverse evaluation of starting combustion efficiency is specifically as follows: constructing a group of common working equations for engine starting to perform reverse evaluation on combustion efficiency.

7. The engine starting throttle back calculation method based on test data as claimed in claim 6, characterized in that: The engine starting common working equation group is: ； ； ； ； ； In the formula, The power consumption of the compressor is is the turbine output work, The power consumption is due to the resistance during the starting process. is the high pressure shaft acceleration power, is the starter power, W a3 is the combustion chamber inlet air flow rate, W fb is the fuel flow rate, W g4 is the combustion chamber outlet gas flow rate, W g9 is the engine outlet gas flow rate, n OB is the engine speed control variable, n is the relative physical speed, W fb_OB The fuel flow control amount.

8. The engine starting throttle back calculation method based on test data as claimed in claim 1, characterized in that: The approximate calculation of the pre-ignition starting process is specifically as follows: Establish an engine starting performance calculation model to obtain the relationship between starter power and relative physical speed; The starter power is selected to have a cubic relationship with the ignition speed, and the relative physical speed is selected to have a linear relationship with the ignition speed; the working point of the ignition speed is selected as the reference point, and the engine compressor work, turbine work and total temperature before the turbine are obtained by interpolating the speed between zero speed and ignition speed, and the starter power at the current time t is obtained according to the starter characteristics; At time t+Δt, the relative physical speed n at the previous moment t is used as the initial value at the current moment, the starter power is calculated repeatedly, and then the rotor acceleration rate is calculated according to the rotor dynamics equation. dn / dt , then according to the formula n t+Δt =n t +dn / dt , regain n 1 t+Δt Repeat this process until the n Calculated times n n t+Δt Convergence, calculation ends, and the speed at the current moment is obtained n t+Δt ; Determine the current speed n t+Δt Whether the ignition speed is reached, if not, the speed calculation is performed again at different times until the speed reaches the ignition speed, completing the starting performance calculation before ignition.

Images