Engine overall simulation modeling method and system based on distributed power system

Abstract

The application relates to the technical field of power system simulation, and solves the problem that there is currently a lack of corresponding overall performance calculation models of complete machines developed according to the layout characteristics of distributed power systems, specifically an engine overall simulation modeling method and system based on a distributed power system, and an overall performance calculation model of a tip turbine fan engine is established, which comprises the following steps: modeling each component along the airflow direction; using a design point algorithm and a non-design point algorithm to establish the overall performance calculation model; and establishing an air generator-tip turbine fan engine overall calculation model, which comprises the following steps: performing overall performance calculation of the air generator; taking the air supply parameters as the internal content air intake parameters of an auxiliary engine, and using the overall performance calculation model of the tip turbine fan engine to complete simulation calculation. A mathematical calculation model of a tip turbine fan engine suitable for simulation design of a distributed air path connected power system of a vertical / short take-off and landing aircraft is established.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power system simulation technology, in particular to an engine overall simulation modeling method and system based on a distributed power system. BACKGROUND

[0002] The distributed gas path connection configuration power system uses a configuration of one main engine + multiple auxiliary engines; wherein the main engine provides a high-pressure compressed gas source to the auxiliary engines, and the main and auxiliary engines are connected through a gas path without a mechanical transmission system. The main engine is an air generator mainly used to provide a high-pressure gas source and shaft power to the auxiliary engines. The auxiliary engines are multiple (2 / 4, etc.) tip turbine fan engines (high-bypass-ratio turbofans) that do not need a compressor component because the high-pressure airflow into the combustion chamber is directly provided by the main engine, and thus the speed-increasing gearbox connecting the tip turbine and the compressor is also removed.

[0003] The air generator (main engine) mainly provides shaft power or compressed air, and mainly has two configurations of core engine bleed air and load compressor bleed air. The air generator (main engine) uses a component method for overall performance modeling. The modeling steps are as follows: first, model and connect each component in the order of airflow passing through, then perform aerodynamic and thermodynamic calculations on each component from front to back to obtain the aerodynamic and thermodynamic parameters of the inlet and outlet of each component, and finally obtain the overall performance parameters of the air generator.

[0004] The tip turbine fan engine is different from the axial series layout of the fan, compressor, combustion chamber, turbine, etc. of the conventional turbofan engine in configuration. The combustion chamber and turbine are arranged outside the fan, the integrated turbine-fan is placed behind the combustion chamber, the turbine blades are arranged at the fan tip, and the compressor is driven by the integrated turbine-fan component through a speed-increasing gearbox, which greatly shortens the axial length of the engine. The overall performance modeling is usually performed using a component method, and the modeling method of the component is similar to that of the air generator component. In the distributed gas path connection configuration power system, the auxiliary engine used is a tip turbine fan engine without a compressor and a speed-increasing gearbox. Due to the structural changes, the calculation mathematical model for overall performance modeling of the original tip turbine fan engine needs to be adjusted.

[0005] The overall performance simulation calculation of the main engine is relatively mature, but the overall performance simulation calculation technology of the tip turbine fan engine without a compressor has not been developed, and the performance calculation model is still blank. Due to the change in the structure of the tip turbine fan engine without a compressor and a speed increasing gear box, the existing mathematical model for the overall performance calculation of the engine is no longer applicable. In addition, the overall performance joint simulation calculation of the main engine and the auxiliary engine is also blank, and the aerodynamic coupling calculation mathematical model of the air generator and the tip turbine fan engine is relatively independent. Therefore, it is urgent to propose an overall simulation model of a distributed power system based on a tip turbine fan engine to support the simulation design work of the entire distributed power system. SUMMARY

[0006] In view of the deficiencies in the prior art, the present application provides an engine overall simulation modeling method and system based on a distributed power system, which aims to establish a mathematical calculation model of a tip turbine fan engine without a compressor and an aerodynamic coupling calculation model of an air generator (main engine) and a tip turbine fan engine (auxiliary engine), improve the adaptability of the algorithm, and solve the problem of the lack of a corresponding overall performance calculation model developed for the layout characteristics of the distributed power system.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical scheme: an engine overall simulation modeling method based on a distributed power system, which comprises establishing a tip turbine fan engine overall performance calculation model and establishing an air generator-tip turbine fan engine overall calculation model.

[0008] The establishment of the tip turbine fan engine overall performance calculation model comprises the following steps:

[0009] The component method is adopted to model each component of the engine one by one along the airflow direction;

[0010] The design point algorithm and the non-design point algorithm are used to establish the overall performance calculation model of the tip turbine fan engine from the inlet to the outlet;

[0011] The establishment of the air generator-tip turbine fan engine overall calculation model comprises the following steps:

[0012] The overall performance calculation of the air generator is performed to determine the air supply parameters of the air generator;

[0013] The air supply parameters are used as the internal intake parameters of the auxiliary engine, and the simulation calculation is completed by using the tip turbine fan engine overall performance calculation model.

[0014] Preferably, the component method refers to modeling and connecting each component of the modeling object in sequence according to the airflow flowing through, and then respectively calculating the aerodynamic thermal parameters of the inlet and outlet of each component from front to back to obtain the overall performance parameters of the air generator.

[0015] Preferably, the calculation steps of the design point algorithm include,

[0016] Calculating the engine inlet airflow parameters: obtaining the flight altitude and Mach number of the engine, and calculating the atmospheric parameters and engine inlet airflow parameters according to the flight altitude and Mach number;

[0017] Sequentially calculating the engine outer-bypass component parameters, the outer-bypass component including an outer-bypass inlet, an outer-bypass fan, an outer-bypass duct, and an outer-bypass nozzle;

[0018] Sequentially calculating the engine related component parameters: the related component including an air system, a combustion chamber, a turbine, and an inner-bypass nozzle;

[0019] Calculating the engine overall performance.

[0020] Preferably, the calculation of the engine outer-bypass component parameters includes the following steps:

[0021] Obtaining the inlet total pressure recovery coefficient, and calculating the outer-bypass inlet outlet airflow parameters according to the inlet total pressure recovery coefficient;

[0022] Obtaining the fan design point pressure ratio, efficiency, inner-bypass air flow, and engine bypass ratio, and calculating the outer-bypass fan power and outer-bypass fan outlet airflow parameters according to the fan design point pressure ratio, efficiency, inner-bypass air flow, and engine bypass ratio;

[0023] Obtaining the outer-bypass duct airflow total pressure recovery coefficient, and calculating the outer-bypass duct outlet parameters according to the outer-bypass duct airflow total pressure recovery coefficient;

[0024] Obtaining the atmospheric pressure and outer-bypass nozzle thrust coefficient, and calculating the thrust, outlet area, and gas parameters of the outer-bypass nozzle according to the atmospheric pressure and outer-bypass nozzle thrust coefficient.

[0025] Preferably, the calculation of the engine related component parameters includes the following steps:

[0026] First, obtaining the high-pressure compressed air parameters provided by the air generator, the high-pressure air pipeline total pressure loss, and the cooling and sealing sealing air proportion of high-temperature components such as turbines, and calculating the airflow parameters entering the combustion chamber;

[0027] Then, obtaining the turbine pre-temperature and combustion chamber total pressure recovery coefficient, and calculating the fuel flow and outlet gas parameters of the combustion chamber according to the turbine pre-temperature and combustion chamber total pressure recovery coefficient;

[0028] Finally, the turbine and the inner-duct nozzle are calculated.

[0029] Preferably, the calculation of the turbine and the inner-duct nozzle comprises the following steps:

[0030] Firstly, the turbine guide vane cold air amount, the extracted shaft power, the turbine efficiency and the turbine working vane cold air amount are obtained, the guide vane cooling calculation is performed according to the turbine guide vane cold air amount, and the gas parameters entering the turbine working vane are obtained according to the guide vane cooling calculation;

[0031] Secondly, the turbine working vane outlet parameters are calculated according to the shaft power and the turbine efficiency;

[0032] Then, the working vane cooling calculation is performed according to the turbine working vane cold air amount, and the turbine outlet gas parameters are obtained according to the working vane cooling calculation;

[0033] Finally, the atmospheric pressure and the inner-duct nozzle thrust coefficient are obtained, and the thrust, the outlet area and the gas parameters of the inner-duct nozzle are calculated according to the atmospheric pressure and the inner-duct nozzle thrust coefficient.

[0034] Preferably, the calculation of the engine overall performance is performed by calculating the total thrust and the specific fuel consumption of the engine according to the thrust and the gas parameters of the inner-duct nozzle and the outer-duct nozzle.

[0035] Preferably, the calculation steps of the non-design point algorithm comprise:

[0036] Four independent free variables of the tip turbine engine are selected, and the four independent free variables comprise: the fan relative physical rotating speed, the fan working point position auxiliary coordinate on the characteristic map, the tip turbine working point position auxiliary coordinate on the characteristic map and the tip turbine front temperature.

[0037] According to the principle of the common work of engine components, an engine steady-state working equation set is built, and the engine steady-state working equation set comprises: a first balance equation, a second balance equation, a third balance equation and a fourth balance equation.

[0038] The first balance equation is a combustion chamber outlet and tip turbine inlet flow balance equation.

[0039] The second balance equation is a fan and tip turbine power balance equation.

[0040] The third balance equation is a tip turbine outlet and inner-duct nozzle flow balance equation.

[0041] The fourth balance equation is a fan outlet and bypass nozzle flow balance equation / inner and outer bypass flow mixing static pressure balance equation, the fan outlet and bypass nozzle flow balance equation is applied to an inner and outer bypass separated exhaust turbine engine, and the inner and outer bypass flow mixing static pressure balance equation is applied to a mixed exhaust turbine engine.

[0042] Preferably, the combustion chamber outlet and turbine inlet flow balance equation is E(1)=(W g41,cor -W g41,cor,map ) / W g41,cor , wherein W g41,cor is turbine working blade inlet converted flow, and W g41,cor,map is interpolated converted flow from a turbine characteristic diagram.

[0043] The fan and turbine power balance equation is E(2)=(L th -L f ) / L th , wherein L th is turbine power, and L f is fan power.

[0044] The turbine outlet and inner bypass nozzle flow balance equation is E(3)=(P6-P8) / P6, wherein P6 is inner bypass nozzle inlet total pressure, and P8 is inner bypass nozzle outlet total pressure.

[0045] The fan outlet and bypass nozzle flow balance equation is E(4)=(P 16 -P 18 ) / P 16 , wherein P 16 is bypass nozzle inlet total pressure, and P 18 is bypass nozzle outlet total pressure.

[0046] The inner and outer bypass flow mixing static pressure balance equation is E(4)=(Ps 163 -Ps 63 ) / Ps 63 , wherein Ps 163 is outer bypass mixing static pressure, and Ps 63 is inner bypass mixing static pressure.

[0047] Preferably, the engine overall simulation modeling system comprises,

[0048] An auxiliary engine calculation module is used to establish a turbine fan engine overall performance calculation model.

[0049] An overall coupling calculation module is used to establish an air generator-turbine fan engine overall calculation model.

[0050] Preferably, the auxiliary engine calculation module comprises:

[0051] The acquisition unit is used for acquiring the unique configuration of the tip turbine fan engine, i.e., a tip turbine-fan integrated engine and an engine without an inter-duct compressor;

[0052] The modeling unit is used for modeling each component of the engine in sequence along the airflow direction by using the component method idea;

[0053] The calculation unit is used for establishing the overall performance calculation model of the tip turbine fan engine from the inlet to the outlet by using the design point algorithm and the off-design point algorithm according to the flow balance and the power balance and the like.

[0054] Preferably, the overall coupling calculation module comprises:

[0055] The analysis unit is used for performing the overall performance calculation of the air generator and determining the air supply parameters of the air generator, the air supply parameters including the flow rate, the temperature and the pressure;

[0056] The simulation unit is used for taking the air supply parameters as the inter-duct inlet parameters of the auxiliary engine and completing the simulation calculation by using the overall performance calculation model of the tip turbine fan engine.

[0057] Compared with the prior art, the present application provides the engine overall simulation modeling method and system based on the distributed power system, and has the following beneficial effects:

[0058] 1. The present application proposes the overall performance calculation model of the tip turbine fan engine without a compressor and the simulation modeling method of the corresponding model, solves the problem of the simulation modeling technology of the tip turbine fan engine (auxiliary engine) without a compressor, without a connecting tip turbine and a speed increasing gearbox of a compressor in the distributed air path connection configuration power system at present, and establishes the mathematical calculation model of the tip turbine fan engine suitable for the simulation design of the distributed air path connection power system of the vertical / short take-off and landing aircraft.

[0059] 2. The present application establishes the aerodynamic coupling calculation model of the air generator (main engine) and the tip turbine fan engine (auxiliary engine), improves the adaptability of the algorithm, and provides support for the simulation design of the entire distributed power system through the overall performance joint simulation calculation of the main engine and the auxiliary engine.

[0060] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be achieved and obtained by the structure indicated in the description and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0061] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are only some embodiments of the present application, and the other drawings can be obtained by those skilled in the art without any creative effort based on these drawings.

[0062] Figure 1 A high-pressure air generator + 4 tip turbine fan engine layout schematic diagram according to an embodiment of the present application is shown.

[0063] Figure 2 A schematic diagram of a tip turbine fan engine with a compressor split according to the prior art is shown.

[0064] Figure 3 A schematic diagram of a tip turbine fan engine without a compressor split according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0065] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely explain the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the scope of protection of the present application.

[0066] As shown in Figure 1 A high-pressure air generator + 4 tip turbine fan engine layout schematic diagram according to an embodiment of the present application is shown. At present, the distributed air path connection power system for vertical / short take-off and landing aircraft uses a main engine + multiple auxiliary engine configuration. The main engine provides high-pressure compressed air source to the auxiliary engine, and the main and auxiliary engines are connected through the air path without a mechanical transmission system. The main engine is an air generator, which mainly provides high-pressure air source and power extraction to the auxiliary engine. Figure 1 The auxiliary engine is four tip turbine fan engines (large bypass ratio turbofan). Since the inner bypass high-pressure air flow entering the combustion chamber is directly provided by the main engine, the compressor component is not needed, and thus the speed-up gearbox connecting the tip turbine and the compressor is also removed.

[0067] The overall performance simulation calculation of the main engine (air generator) is mature; but the overall performance simulation calculation of the uncompressor tip turbine fan engine (auxiliary engine) still needs to be studied, the power configuration of the uncompressor tip turbine fan engine (auxiliary engine) has not been proposed before, and the performance calculation model thereof is still blank at present. In addition, the overall performance joint simulation calculation of the main engine and the auxiliary engine is also blank; in order to support the simulation design and the like of the entire distributed power system, the engine overall simulation modeling method and system based on the distributed power system are proposed.

[0068] The main function of the air generator is to provide shaft power or compressed air, and the essence of the air generator is a gas turbine engine. The air generator mainly has two configurations of core engine bleed air and load compressor bleed air. The air generator is modeled by using the component method; specifically, when the overall performance of the air generator is modeled by using the component method, each component is modeled and connected in series according to the order of the airflow flowing through, and then the aerodynamic and thermal calculation of each component is performed from front to back to obtain the aerodynamic and thermal parameters of the inlet and outlet of each component, and finally the overall performance parameters of the entire air generator are obtained.

[0069] In the distributed air path connection power system for vertical / short take-off and landing aircraft, the configuration of one main engine + multiple auxiliary engines is used. Since the auxiliary engine (tip turbine fan engine) removes the compressor and the speed increasing gearbox, the existing overall performance calculation mathematical model of the engine is no longer applicable. In addition, the overall performance modeling of the main engine (air generator) and the auxiliary engine (tip turbine fan engine) is relatively independent, and the aerodynamic coupling calculation mathematical model of the two needs to be established.

[0070] As shown in Figure 2 , a structure schematic diagram of an existing split-type tip turbine fan engine with a compressor is shown, and the tip turbine fan engine mainly comprises an inlet duct, an outer-duct fan, an inner-duct compressor, a combustion chamber, a tip turbine, an exhaust nozzle and a speed increasing gearbox. The tip turbine fan engine is different from the fan, compressor, combustion chamber and turbine of the conventional turbofan engine in that the combustion chamber and the turbine are arranged outside the fan, the integrated turbine-fan is arranged behind the combustion chamber, the turbine blades are arranged at the fan blade tip, and the compressor is driven by the integrated turbine-fan through the speed increasing gearbox. This configuration greatly shortens the axial length of the engine. The component method is usually used to model the overall performance of the split-type tip turbine fan engine with a compressor. The steps of modeling the tip turbine fan engine by using the component method are similar to those of modeling the air generator.

[0071] As shown in Figure 3As shown in Fig. 1, a schematic diagram of a split-ducted tip turbine fan engine without a compressor is shown. The high pressure air flow into the inner duct of the combustion chamber of the split-ducted tip turbine fan engine is directly provided by the main engine, thus without a compressor component, and the speed increasing gearbox connecting the tip turbine and the compressor is also removed. The tip turbine fan engine is in a split-ducted form, and a mixing chamber for mixing the inner and outer duct air flows can be added to the tip turbine engine as needed, and then the mixed air flow is expanded through the tail nozzle and discharged into the atmosphere.

[0072] In combination Figure 1 and Figure 3 , the corresponding power system principle of the present technology is as follows: the main engine (air generator) provides high pressure air source for multiple auxiliary engines (tip turbine fan engines), the distributed auxiliary engines generate thrust to provide vertical take-off and landing or short take-off power for the aircraft. Since the auxiliary engine does not have a compressor, the high pressure compressed air directly enters the auxiliary engine combustion chamber for combustion to generate high temperature and high pressure gas, which enters the tip turbine and drives the turbine to work, and then enters the inner duct nozzle for expansion and discharge into the atmosphere. Since the tip turbine and the fan are integrated components, the turbine directly drives the fan to rotate, compresses the outer duct air flow, and then expands through the outer duct nozzle and discharges into the atmosphere. The distributed power system is essentially equivalent to a large bypass ratio turbofan engine. As shown in Fig. 2, the combustion chamber and turbine of the auxiliary engine can be regarded as a part of the equivalent turbofan engine, i.e., the combustion chamber of the four auxiliary engines plus the combustion chamber of the air generator is equivalent to the combustion chamber of the turbofan engine, the turbine of the four auxiliary engines plus the turbine of the air generator is equivalent to the turbine of the turbofan engine, the fan of the four auxiliary engines is equivalent to the fan of the turbofan engine, and the compressor of the air generator is the same as the compressor of the equivalent turbofan engine. Therefore, the changes in various parameters of the main and auxiliary engines are consistent. Figure 1

[0073] The present application develops an engine overall simulation modeling method based on the layout characteristics of the distributed power system, which includes: establishing a tip turbine fan engine overall performance calculation model and an air generator-tip turbine fan engine whole machine calculation model.

[0074] The establishment of the tip turbine fan engine overall performance calculation model includes the following steps: (1) obtaining the specific configuration of the tip turbine fan engine: tip turbine-fan integrated engine, and engine without an inner duct compressor; (2) using the component method idea to model each component of the engine one by one along the airflow direction; (3) using the design point algorithm and the non-design point algorithm to establish the overall performance calculation model of the tip turbine fan engine from the inlet to the outlet according to the flow balance and power balance relationships;

[0075] ​The steps for establishing the air generator-ducted fan engine overall calculation model include the following: (1) performing overall performance calculation of the air generator to determine air supply parameters of the air generator, including flow rate, temperature and pressure; and (2) taking the air supply parameters as the internal inlet air parameters of the auxiliary engine, and performing simulation calculation by using the overall performance calculation model of the ducted fan engine.

[0076] The component method refers to modeling each component of the modeling object in sequence according to the sequence of airflow passing through, and then performing aerodynamic and thermal calculation on each component from front to back to obtain aerodynamic and thermal parameters at the inlet and outlet of each component, and finally obtaining overall performance parameters of the air generator.

[0077] The calculation steps of the design point algorithm include: (1) calculating engine inlet airflow parameters: obtaining the flight altitude and Mach number of the engine, and calculating atmospheric parameters (temperature, pressure, etc.) and engine inlet airflow parameters according to the flight altitude and Mach number; (2) sequentially calculating engine outer duct component parameters, including outer duct inlet, outer duct fan, outer duct and outer duct nozzle; (3) sequentially calculating engine related component parameters: related components include air system, combustion chamber, turbine and inner duct nozzle; and (4) calculating overall performance of the engine.

[0078] The calculation of the engine outer duct component parameters includes the following steps: (1) obtaining the inlet total pressure recovery coefficient, and calculating the outer duct inlet outlet airflow parameters according to the inlet total pressure recovery coefficient; (2) obtaining the fan design point pressure ratio, efficiency, inner duct air flow rate and engine duct ratio, and calculating the outer duct fan power and outer duct fan outlet airflow parameters according to the fan design point pressure ratio, efficiency, inner duct air flow rate and engine duct ratio; (3) obtaining the outer duct airflow total pressure recovery coefficient, and calculating the outer duct outlet parameters according to the outer duct airflow total pressure recovery coefficient; and (4) obtaining the atmospheric pressure and outer duct nozzle thrust coefficient, and calculating the thrust, outlet area and gas parameters of the outer duct nozzle according to the atmospheric pressure and outer duct nozzle thrust coefficient.

[0079] The calculation of the engine related component parameters includes the following steps: (1) first obtaining high-pressure compressed air parameters provided by the air generator, high-pressure air pipeline total pressure loss, and cooling and sealing air supply proportion of high-temperature components such as turbine, and calculating the airflow parameters entering the combustion chamber; (2) then obtaining the turbine pre-temperature and the combustion chamber total pressure recovery coefficient, and calculating the fuel flow rate and outlet gas parameters of the combustion chamber according to the turbine pre-temperature and the combustion chamber total pressure recovery coefficient; and (3) finally performing calculation of the turbine and the inner duct nozzle.

[0080] The calculation of the turbine and the inner-duct nozzle comprises the following steps: (1) obtaining the turbine guide vane cold air quantity, the extracted shaft power, the turbine efficiency and the turbine working vane cold air quantity, performing guide vane cooling calculation according to the turbine guide vane cold air quantity, and obtaining the gas parameters entering the turbine working vane according to the guide vane cold air calculation; (2) calculating the turbine working vane outlet parameters according to the shaft power and the turbine efficiency; (3) performing working vane cooling calculation according to the turbine working vane cold air quantity, and obtaining the turbine outlet gas parameters according to the working vane cooling calculation; (4) finally obtaining the atmospheric pressure and the inner-duct nozzle thrust coefficient, and calculating the thrust, the outlet area and the gas parameters of the inner-duct nozzle according to the atmospheric pressure and the inner-duct nozzle thrust coefficient.

[0081] The calculation of the engine overall performance is to calculate the engine total thrust and the specific fuel consumption by the thrust and the gas parameters of the inner-duct nozzle and the outer-duct nozzle. The main purpose of the engine non-design point performance calculation is to find the working point of the engine at the non-design working condition. Since the characteristics of each component of the engine are nonlinear curves, when the mathematical model of the engine is established by using the component method, only according to the known parameters, the characteristics of each component and the mutual restriction relationship of the common work of each component, the calculation is performed from the inlet section of the engine and is performed section by section according to the flow process of the gas flow. For the fan and the blade tip turbine rotor components, two parameters (the converted rotating speed and the auxiliary coordinate) are required to determine the positions of the components on the characteristic diagram.

[0082] The calculation steps of the off-design point algorithm include: (1) selecting four independent free variables of the tip turbine engine of the non-pressure compressor, the four independent free variables including: the relative physical speed (or the relative converted speed) of the fan, the auxiliary coordinate (such as the β line) of the working point position of the fan on the characteristic map, the auxiliary coordinate (such as the β line) of the working point position of the tip turbine on the characteristic map, and the temperature before the tip turbine; after trying the above parameters, the engine common working conditions are checked and determined. If the common working conditions are met, the calculated parameter values are the engine working parameters in the corresponding state. Otherwise, the independent variables need to be adjusted and the iteration calculation is performed again until the common working conditions are met. (2) According to the principle of engine component common working, the engine steady working equation set (residual equation set) is built, and the tip turbine engine needs to meet the following four common working conditions, and there are four balance equations corresponding to the steady-state model; the engine steady working equation set includes: the first balance equation, the second balance equation, the third balance equation, and the fourth balance equation; the first balance equation is the flow balance equation of the combustor outlet and the tip turbine inlet; the second balance equation is the fan and tip turbine power balance equation; the third balance equation is the tip turbine outlet and the inner bypass nozzle flow balance equation; the fourth balance equation is the fan outlet and the outer bypass nozzle flow balance equation / the static pressure balance equation when the inner and outer bypass air flows are mixed, the fan outlet and the outer bypass nozzle flow balance equation is applied to the inner and outer dual bypass exhaust tip turbine engine, and the static pressure balance equation when the inner and outer bypass air flows are mixed is applied to the mixed exhaust tip turbine engine.

[0083] The flow balance equation of the combustor outlet and the tip turbine inlet is: E(1) = (W g41,cor -W g41,cor,map ) / W g41,cor , wherein W g41,cor is the converted flow of the turbine working blade inlet, and W g41,cor,map is the converted flow of the interpolation on the turbine characteristic map; the fan and tip turbine power balance equation is: E(2) = (L th -L f ) / L th , wherein Lth is the tip turbine power, and L f is the fan power; the tip turbine outlet and the inner bypass nozzle flow balance equation is: E(3) = (P6-P8) / P6, wherein P6 is the total pressure of the inner bypass nozzle inlet, and P8 is the total pressure of the inner bypass nozzle outlet; the fan outlet and the outer bypass nozzle flow balance equation is: E(4) = (P 16 -P 18 ) / P 16 , wherein P 16 is the total pressure of the outer bypass nozzle inlet, and P 18 is the total pressure of the outer bypass nozzle outlet; the static pressure balance equation when the inner and outer bypass air flows are mixed is: E(4) = (Ps163 -Ps 63 ) / Ps 63 Where, Ps 163 is the outer mixed static pressure, Ps 63 is the inner mixed static pressure. In summary, the number of independent variables and the number of balance equations are equal, the equation set is closed, and the common working nonlinear equation set can be solved by using Newton iteration method or the like.

[0084] The application provides an engine overall simulation modeling system based on a distributed power system, which comprises: (1) an auxiliary engine calculation module, which is used for establishing an overall performance calculation model of a tip turbine fan engine; and (2) an overall coupling calculation module, which is used for establishing an air generator-tip turbine fan engine overall calculation model.

[0085] The auxiliary engine calculation module comprises: (1) an acquisition unit, which is used for acquiring specific configurations of the tip turbine fan engine, i.e., a tip turbine-fan component integrated engine and an engine without an inner channel compressor; (2) a modeling unit, which is used for modeling each component of the engine one by one along the airflow direction by using the component method thought; and (3) a calculation unit, which is used for establishing an overall performance calculation model of the tip turbine fan engine from the inlet to the outlet by using a design point algorithm and a non-design point algorithm according to flow balance and power balance and the like.

[0086] The overall coupling calculation module comprises: (1) an analysis unit, which is used for performing overall performance calculation of the air generator and determining air supply parameters of the air generator, wherein the air supply parameters comprise flow, temperature and pressure; and (2) a simulation unit, which is used for taking the air supply parameters as inner channel inlet air parameters of the auxiliary engine and completing simulation calculation by using the overall performance calculation model of the tip turbine fan engine. The air generator is essentially a gas turbine engine, and its overall performance calculation model is very mature, and several simulation calculation commercial software can be used.

[0087] The key of the overall performance coupling calculation of the air generator and the tip turbine fan engine lies in the determination of the air supply parameters (i.e., the tip turbine engine inner channel inlet air parameters, including flow, temperature and pressure) of the air generator.

[0088] In order to obtain better auxiliary engine performance, the air supply flow ratio of the air generator should be adjustable in a small range. Therefore, in the non-design point calculation of the power system, the air supply flow ratio (relative to the air flow of the air generator inlet) of the air generator is an independent variable for the air generator, and the change of the air supply flow ratio will cause the change of the overall state of the air generator, and the corresponding inlet pressure and temperature also change.

[0089] Taking a single-shaft air generator as an example, the common working equation is as follows:

[0090] (1) Flow balance equation between combustion chamber outlet and turbine inlet;

[0091] (2) Compressor and turbine power balance equations;

[0092] (3) Flow balance equation between turbine outlet and nozzle inlet;

[0093] The single-shaft air generator has five independent variables: the relative physical speed of the compressor (or relative converted speed), the auxiliary coordinates of the compressor's operating point position on the characteristic diagram, the auxiliary coordinates of the turbine's operating point position on the characteristic diagram, the turbine front temperature, and the air supply flow ratio of the air generator.

[0094] For the entire power system, the air generator and tip turbine have a total of seven equilibrium equations, with a total of nine independent variables. This number outnumbers the number of independent variables, requiring the specification of two independent variable values ​​(i.e., control laws) to close the common operating equations for the power system and determine its operating state. This allows the air generator and tip turbine to be controlled relatively independently, resulting in more efficient control of the main and auxiliary engines.

[0095] The present invention establishes a mathematical calculation model of a blade tip turbine turbofan engine without a compressor and an aerodynamic coupling calculation model of an air generator (main engine) and a blade tip turbine turbofan engine (auxiliary engine), thereby improving the adaptability of the algorithm.

[0096] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. The overall simulation modeling method of the engine based on the distributed power system is characterized by: The overall simulation modeling method includes establishing an overall performance calculation model of the blade tip turbofan engine and establishing an air generator-blade tip turbofan engine whole machine calculation model; The establishment of the blade tip turbofan engine overall performance calculation model comprises the following steps: Using the component approach, each engine component is modeled one by one along the airflow direction; The overall performance calculation model of the blade tip turbofan engine from inlet to outlet is established using the design point algorithm and the non-design point algorithm. The calculation steps of the design point algorithm include calculating the engine inlet airflow parameters: obtaining the flight altitude and Mach number of the engine, and calculating the atmospheric parameters and the engine inlet airflow parameters according to the flight altitude and Mach number; sequentially calculating the parameters of the engine outer components, the outer components including the outer intake duct, the outer fan, the outer duct and the outer nozzle; sequentially calculating the parameters of the engine related components, the related components including the air system, the combustion chamber, the turbine and the inner nozzle; and calculating the overall engine performance. The calculation steps of the non-design point algorithm include: selecting four independent free variables of the blade tip turbine engine, the four independent free variables include: the relative physical speed of the fan, the auxiliary coordinates of the working point position of the fan on the characteristic diagram, the auxiliary coordinates of the working point position of the blade tip turbine on the characteristic diagram, and the temperature before the blade tip turbine; according to the principle of the joint operation of the engine components, constructing a steady-state working equation group of the engine, the steady-state working equation group of the engine includes: a first balance equation, a second balance equation, a third balance equation, and a fourth balance equation; the first balance equation is a flow balance equation between the combustion chamber outlet and the blade tip turbine inlet; the second balance equation is a power balance equation between the fan and the blade tip turbine; the third balance equation is a flow balance equation between the blade tip turbine outlet and the inner nozzle; the fourth balance equation is a flow balance equation between the fan outlet and the outer nozzle / a static pressure balance equation when the inner and outer nozzle airflows are mixed, the fan outlet and the outer nozzle flow balance equation is applied to the inner and outer double duct separate exhaust blade tip turbine engine, and the static pressure balance equation when the inner and outer nozzle airflows are mixed is applied to the mixed exhaust blade tip turbine engine; The establishment of the air generator-tip turbofan engine whole machine calculation model comprises the following steps: Calculate the overall performance of the air generator and determine the air supply parameters of the air generator; The air supply parameters are used as the implicit air intake parameters of the auxiliary engine, and the overall performance calculation model of the blade tip turbofan engine is used to complete the simulation calculation.

2. The engine overall simulation modeling method based on a distributed power system according to claim 1 is characterized in that: The component method refers to modeling the components of the modeling object and connecting them in series according to the order of airflow, and then performing aerodynamic and thermal calculations on each component from front to back to obtain the aerodynamic and thermal parameters of the inlet and outlet of each component, and finally obtain the overall performance parameters of the air generator.

3. The engine overall simulation modeling method based on a distributed power system according to claim 1 is characterized in that: The calculation of the engine external component parameters includes the following steps: Obtaining an intake duct total pressure recovery coefficient, and calculating an outlet airflow parameter of the outer duct according to the intake duct total pressure recovery coefficient; Obtaining the fan design point pressure ratio, efficiency, internal air flow rate, and engine bypass ratio, and calculating the external fan power and external fan outlet airflow parameters based on the fan design point pressure ratio, efficiency, internal air flow rate, and engine bypass ratio; Obtaining a total pressure recovery coefficient of the duct airflow, and calculating duct outlet parameters according to the total pressure recovery coefficient of the duct airflow; Atmospheric pressure and a ducted nozzle thrust coefficient are obtained, and thrust, an outlet area, and gas parameters of the ducted nozzle are calculated based on the atmospheric pressure and the ducted nozzle thrust coefficient.

4. The engine overall simulation modeling method based on a distributed power system according to claim 1 is characterized in that: The calculation of the engine-related component parameters includes the following steps: First, obtain the high-pressure compressed air parameters provided by the air generator, the total pressure loss of the high-pressure air pipeline, and the cooling and sealing air ratio of high-temperature components such as the turbine, and calculate the airflow parameters entering the combustion chamber; Then, the turbine inlet temperature and the combustion chamber total pressure recovery coefficient are obtained, and the fuel flow rate and outlet gas parameters of the combustion chamber are calculated based on the turbine inlet temperature and the combustion chamber total pressure recovery coefficient; Finally, the turbine and internal nozzle are calculated.

5. The engine overall simulation modeling method based on a distributed power system according to claim 4 is characterized in that: The calculation of the turbine and the internal nozzle includes the following steps: First, the turbine guide vane cooling air volume, extracted shaft power, turbine efficiency, and turbine blade cooling air volume are obtained, guide vane cooling calculation is performed based on the turbine guide vane cooling air volume, and gas parameters entering the turbine blades are obtained based on the guide vane cooling air calculation; Then, the turbine blade outlet parameters are calculated according to the shaft power and turbine efficiency; Then, a working blade cooling calculation is performed according to the cooling air amount of the turbine working blade, and turbine outlet gas parameters are obtained according to the working blade cooling calculation; Finally, the atmospheric pressure and the thrust coefficient of the embodied nozzle are obtained, and the thrust, the outlet area and the gas parameters of the embodied nozzle are calculated according to the atmospheric pressure and the thrust coefficient of the embodied nozzle.

6. The overall engine simulation modeling method based on a distributed power system according to claim 1, characterized in that: The calculation of the overall engine performance is to calculate the total thrust and fuel consumption rate of the engine through the thrust and gas parameters of the inner nozzle and the outer nozzle.

7. The engine overall simulation modeling method based on a distributed power system according to claim 1 is characterized in that: The flow balance equation between the combustion chamber outlet and the blade tip turbine inlet is: ,in, is the converted flow rate at the turbine blade inlet, The flow rate is converted from the interpolation on the turbine characteristic diagram; The fan and tip turbine power balance equation is: ,in, is the turbine power at the blade tip, is the fan power; The flow balance equation between the tip turbine outlet and the internal nozzle is: ,in, is the total pressure at the nozzle inlet, is the total pressure at the outlet of the connotative nozzle; The flow balance equation between the fan outlet and the duct nozzle is: ,in, is the total pressure at the culvert nozzle inlet, is the total pressure at the culvert nozzle outlet; The static pressure balance equation when the inner and outer air flows are mixed is: ,in, is the static pressure of the bypass mixing, It is the internal mixed static pressure.

8. The overall engine simulation modeling system based on distributed power system is characterized by: Used to execute the engine overall simulation modeling method based on a distributed power system according to any one of claims 1 to 7, the engine overall simulation modeling system includes: Auxiliary engine calculation module: used to establish the overall performance calculation model of the blade tip turbofan engine; Overall coupling calculation module: used to establish the calculation model of the air generator-blade tip turbofan engine.

9. The engine overall simulation modeling system based on the distributed power system according to claim 8 is characterized in that: The auxiliary engine calculation module includes: Acquisition unit: used to acquire the unique configuration of the tip turbofan engine: the tip turbine-fan component integrated engine and the engine without duct compressor; Modeling unit: used to model each engine component one by one along the airflow direction using the component method; Calculation unit: used to establish an overall performance calculation model of the blade tip turbofan engine from inlet to outlet based on flow balance and power balance using design point algorithm and non-design point algorithm.

10. The engine overall simulation modeling system based on the distributed power system according to claim 8, characterized in that: The overall coupling calculation module includes: Analysis unit: used to calculate the overall performance of the air generator and determine the air supply parameters of the air generator, including flow rate, temperature and pressure; Simulation unit: used for using the air supply parameters as the implicit air intake parameters of the auxiliary engine and completing simulation calculations using the overall performance calculation model of the blade tip turbofan engine.

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