A method for optimizing variable topology architecture of hydrogen turbine engine based on genetic algorithm

Abstract

The present invention discloses a method for optimizing a variable topology architecture of a hydrogen turbine engine based on a genetic algorithm, comprising establishing a benchmark hydrogen turbine engine; designing a variable topology architecture; applying various unconventional architectures of engines to the benchmark hydrogen turbine engine, so that hydrogen fuel exchanges heat with airflows at different positions in the engine, respectively, to achieve flexible combination of different architectures and flexible change of heat exchange capacity of the same architecture, simulating the variable actual situation when different architectures are simultaneously applied to a hydrogen turbine engine, and establishing a variable topology architecture; establishing an optimization target; in order to minimize the mass compensation effect brought by hydrogen fuel, on the premise of meeting the thrust requirement of the engine, finding an architecture scheme that minimizes the fuel consumption of the hydrogen turbine engine; establishing optimization variables and optimization constraints; implementing optimization and obtaining optimization results, and obtaining a hydrogen turbine engine architecture scheme that minimizes the aircraft mass compensation according to the values ​​of the optimization variables.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogen power, and relates to a method for optimizing a variable topology architecture of a hydrogen turbine engine based on a genetic algorithm. Background Art

[0002] Hydrogen turbine engines are a highly regarded application of hydrogen energy in the aviation industry. Due to the high calorific value and high heat sink characteristics of hydrogen fuel, the traditional aircraft engine architecture cannot fully utilize the heat sink of hydrogen fuel, and its working method is not compatible with hydrogen fuel. Therefore, it is necessary to adopt various unconventional engine architectures, specifically using hydrogen fuel to exchange heat with airflow at different locations inside the engine, thereby improving engine efficiency and reducing engine fuel consumption.

[0003] However, due to the immature development of current hydrogen storage technology, the low hydrogen storage mass fraction and heavy hydrogen storage system, aircraft equipped with hydrogen turbine engines have suffered a large mass compensation. Therefore, it is urgent to reduce the hydrogen fuel consumption of hydrogen turbine engines and reduce the weight of aircraft equipped with hydrogen turbine engines. Although various engine architectures can reduce engine hydrogen fuel consumption, the addition of architectures will also bring certain mass compensation to the engine. Therefore, it is urgent to adopt a variable topology architecture design optimization method to explore the architecture solution that minimizes the mass compensation brought by hydrogen turbine engines and improve the design feasibility of hydrogen turbine engines. Summary of the invention

[0004] The purpose of the present invention is to provide a method for optimizing the variable topology architecture of a hydrogen turbine engine based on a genetic algorithm, so as to obtain a hydrogen turbine engine architecture scheme with the minimum aircraft mass compensation, make full use of the high heat sink characteristics of hydrogen fuel, improve engine efficiency, reduce hydrogen fuel consumption, and reduce the weight of the hydrogen storage system.

[0005] The present invention adopts the following technical solutions:

[0006] A method for optimizing a variable topology architecture of a hydrogen turbine engine based on a genetic algorithm, characterized by comprising the following steps:

[0007] 1) Establish a benchmark hydrogen turbine engine. Select a model of traditional aircraft engine, clarify the thrust requirements of the engine in each flight segment, modify it into a hydrogen turbine engine that meets the requirements, and determine its hydrogen fuel consumption.

[0008] 2) Variable topology architecture design. Apply various unconventional engine architectures to the benchmark hydrogen turbine engine, so that the hydrogen fuel exchanges heat with the airflow at different positions in the engine, and realize flexible combination of different architectures and flexible change of heat exchange of the same architecture, so as to simulate the actual situation when different architectures are applied to hydrogen turbine engines at the same time, and achieve the purpose of establishing a variable topology architecture.

[0009] 3) Establish optimization goals. In order to minimize the mass compensation impact brought by hydrogen fuel, it is necessary to find an architecture solution that minimizes the fuel consumption of the hydrogen turbine engine while meeting the thrust requirements of the engine. However, as the effect of the engine architecture in reducing fuel consumption increases, the heat exchange between the hydrogen fuel and the airflow inside the engine in the architecture will also increase, resulting in an improvement in the design quality of the heat exchanger and an increase in mass compensation. Therefore, when the maximum take-off weight of the aircraft equipped with this type of engine remains unchanged, the increase in the maximum airtime when the aircraft is equipped with a hydrogen turbine engine compared to that of a traditional aircraft is calculated, and the size of the mass compensation brought about by the application of various architectures of the hydrogen turbine engine can be evaluated. A large increase in airtime means low mass compensation; a small increase in airtime means high mass compensation. The specific calculation formula for the increase in airtime is as follows.

[0010]

[0011] Wherein, Δt represents the increment of the airborne time, which is used as an indicator to evaluate the mass compensation brought by the hydrogen turbine engine to the aircraft; t h ydrogen Indicates the airborne time of an aircraft equipped with a hydrogen turbine engine; t traditional Indicates the time a traditional aircraft stays in the air; M f,traditional Indicates the maximum fuel mass that a traditional aircraft can carry; M h eat exch anger represents the increased mass of the heat exchanger after applying various architectures to the hydrogen turbine engine; α represents the hydrogen storage mass fraction; θ cruise Indicates the proportion of engine cruising fuel consumption to total fuel consumption; W f,h ydrogen,cruise represents the hydrogen fuel flow rate under the cruise condition of the hydrogen turbine engine; t remaining legs It represents the time the aircraft spends in the air for the rest of the flight except the cruising phase. The final optimization goal is to maximize the increment of the maximum time the aircraft spends in the air when equipped with a hydrogen turbine engine compared with a traditional aircraft.

[0012] 4) Establish optimization variables and optimization constraints. The establishment of optimization variables should realize the change of engine fuel consumption and the change of heat exchange of each architecture. The value range of each optimization variable should be determined according to the actual situation, and the engine thrust requirement should be selected as one of the optimization constraints. When the optimization variables are changed, the engine thrust should always be maintained to meet the design requirements. The calculation formula is as follows.

[0013] q mg V5-q ma V0+(p5-p0)A5≥T Baseline

[0014] In the formula, the right side of the inequality is T Baselinerepresents the thrust requirement of the benchmark engine; the left side of the inequality is the engine thrust calculation formula, where q mg represents the gas flow rate in the engine, q ma represents the air flow entering the engine, V5 and V0 represent the air flow velocity at the engine tail nozzle outlet and the engine flight speed respectively, p5 and p0 represent the engine tail nozzle outlet pressure and the ambient pressure respectively, and V5 represents the engine tail nozzle outlet area.

[0015] Other optimization constraints mainly include that the engine turbine does not overheat and all engine components meet the balance conditions. The specific formula is as follows.

[0016] The engine turbine does not overheat:

[0017] T4≤T 4,max

[0018] Where T4 represents the actual temperature before the engine turbine, T 4,max Indicates the maximum turbine inlet temperature determined by the engine turbine material.

[0019] The gas flow through the turbine and the air flow through the compressor in the engine remain continuous:

[0020] q mg =q ma -q ma,col +q mf

[0021] In the formula, q mg is the gas flow rate through the turbine in the engine, q ma represents the air flow rate entering the engine, q ma,col represents the amount of cooling air drawn from the compressor, q mf Indicates the fuel flow entering the combustion chamber.

[0022] Compressor and turbine power balance in the engine:

[0023] q ma W c =q mg W t η m

[0024] Where W c Indicates the output power of the compressor, W t represents the turbine power, η m It indicates the energy transfer efficiency when the turbine drives the compressor to rotate.

[0025] 5) Implement optimization and obtain optimization results. According to the above four steps, the genetic algorithm is used for optimization to calculate the maximum airtime increment of the aircraft equipped with the hydrogen turbine engine, and the hydrogen turbine engine architecture scheme that minimizes the aircraft mass compensation can be obtained based on the value of the optimization variable at this time. In addition, the optimization results can be compared with the benchmark hydrogen turbine engine to highlight the optimization effect.

[0026] The beneficial effects of the present invention are as follows:

[0027] 1) A hydrogen turbine engine architecture design scheme is provided, which fully utilizes the high heat sink characteristics of hydrogen fuel, improves engine efficiency, reduces hydrogen fuel consumption, reduces the weight of the hydrogen storage system, improves the design feasibility of the hydrogen turbine engine, and promotes its further application in aviation.

[0028] 2) A method for optimizing the variable topology architecture of a hydrogen turbine engine based on a genetic algorithm is provided. From the perspective of flight-engine integration, the mass compensation (increase in airtime) brought by the hydrogen turbine engine to the aircraft is taken as the optimization target. A method for evaluating the advantages and disadvantages of the engine architecture and obtaining the optimal architecture is given, which has guiding significance for the further development of hydrogen turbine engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a flow chart of a variable topology architecture optimization method for a hydrogen turbine engine based on a genetic algorithm.

[0030] Figure 2 This is a schematic diagram of the variable topology architecture of a certain type of hydrogen turbofan engine.

[0031] Figure 3 This is a comparison chart of the results before and after optimization of the variable topology architecture of a hydrogen turbine engine based on a genetic algorithm. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clear, the technical solution in the present invention is clearly and completely described in conjunction with the drawings in the present invention. The specific examples described here are only used to explain the present invention and are not used to limit the present invention.

[0033] Figure 1 The figure is a flow chart of the hydrogen turbine engine variable topology architecture optimization method based on genetic algorithm. The following will describe in detail the hydrogen turbine engine variable topology architecture optimization process according to the process given in the figure and combined with specific examples.

[0034] 1) Select a certain type of turbofan engine as the benchmark engine, determine its thrust requirements for each flight segment, modify it into a hydrogen turbine engine, and derive the fuel consumption of the engine under cruise conditions when the thrust requirements are met.

[0035] 2) Apply various unconventional engine architectures to the benchmark hydrogen turbine engine, so that the hydrogen fuel can exchange heat with the airflow at different positions in the engine, realize flexible combination of different architectures and flexible change of heat exchange of the same architecture, simulate the actual situation when different architectures are applied to hydrogen turbine engines at the same time, and achieve the purpose of establishing a variable topology architecture. Select three typical hydrogen turbine engine architectures and apply them to the benchmark hydrogen turbine engine to form a variable topology engine architecture. The specific architecture is as follows Figure 2 shown.

[0036] 3) Establish optimization goals. In order to minimize the mass compensation impact brought by hydrogen fuel, it is necessary to find an architecture solution that minimizes the fuel consumption of the hydrogen turbine engine while meeting the thrust requirements of the engine. However, as the effect of the engine architecture in reducing fuel consumption increases, the heat exchange between the hydrogen fuel and the airflow inside the engine in the architecture will also increase, resulting in an improvement in the design quality of the heat exchanger and an increase in mass compensation. Therefore, when the maximum take-off weight of the aircraft equipped with this type of engine remains unchanged, the increase in the maximum airtime when the aircraft is equipped with a hydrogen turbine engine compared to that of a traditional aircraft is calculated, and the size of the mass compensation brought about by the application of various architectures of the hydrogen turbine engine can be evaluated. A large increase in airtime means low mass compensation; a small increase in airtime means high mass compensation. The specific calculation formula for the increase in airtime is as follows.

[0037]

[0038] Wherein, Δt represents the increment of the airborne time, which is used as an indicator to evaluate the mass compensation brought by the hydrogen turbine engine to the aircraft; t h tdrogen Indicates the airborne time of an aircraft equipped with a hydrogen turbine engine; t traditional Indicates the time a traditional aircraft stays in the air; M f,traditional Indicates the maximum fuel mass that a traditional aircraft can carry; M h eat exch anger represents the increased mass of the heat exchanger after applying various architectures to the hydrogen turbine engine; α represents the hydrogen storage mass fraction; θ cruise Indicates the proportion of engine cruising fuel consumption to total fuel consumption; W f,h ydrogen,cruise represents the hydrogen fuel flow rate under the cruise condition of the hydrogen turbine engine; t remaining legs It represents the time the aircraft spends in the air for the rest of the flight except the cruising phase. The final optimization goal is to maximize the increment of the maximum time the aircraft spends in the air when equipped with a hydrogen turbine engine compared with a traditional aircraft.

[0039] The increment of the aircraft's airborne time is selected as the optimization target, and the aircraft's airborne time after being equipped with a hydrogen turbine engine is calculated, and the increment is calculated by comparing it with that of a traditional aircraft. It can be obtained that the maximum airborne time increment of an aircraft equipped with a baseline hydrogen turbine engine is -35.53%.

[0040] 4) Establish optimization variables and optimization constraints. The establishment of optimization variables should realize the change of engine fuel consumption and the change of heat exchange of each architecture. The value range of each optimization variable should be determined according to the actual situation, and the engine thrust requirement should be selected as one of the optimization constraints. When the optimization variables are changed, the engine thrust should always be maintained to meet the design requirements. The calculation formula is as follows.

[0041] q mg V5-q ma V0+(p5-p0)A5≥T Baseline

[0042] In the formula, the right side of the inequality is T Baseline represents the thrust requirement of the benchmark engine; the left side of the inequality is the engine thrust calculation formula, where q mg represents the gas flow rate in the engine, q ma represents the air flow entering the engine, V5 and V0 represent the air flow velocity at the engine tail nozzle outlet and the engine flight speed respectively, p5 and p0 represent the engine tail nozzle outlet pressure and the ambient pressure respectively, and A5 represents the engine tail nozzle outlet area.

[0043] Other optimization constraints mainly include that the engine turbine does not overheat and all engine components meet the balance conditions. The specific formula is as follows.

[0044] The engine turbine does not overheat:

[0045] T4≤T 4,max

[0046] Where T4 represents the actual temperature before the engine turbine, T 4,max Indicates the maximum turbine inlet temperature determined by the engine turbine material.

[0047] The gas flow through the turbine and the air flow through the compressor in the engine remain continuous:

[0048] q mg =q ma -q ma,col +q mf

[0049] In the formula, q mg is the gas flow rate through the turbine in the engine, q ma represents the air flow rate entering the engine, q ma,col represents the amount of cooling air drawn from the compressor, q mf Indicates the fuel flow entering the combustion chamber.

[0050] Compressor and turbine power balance in the engine:

[0051] q ma W c =q mg W t η m

[0052] Where W c Indicates the output power of the compressor, W t represents the turbine power, η m It indicates the energy transfer efficiency when the turbine drives the compressor to rotate.

[0053] Under the cruise condition, the engine fuel consumption and the heat exchange of each structure heat exchanger are selected as optimization variables, and the variable range is determined, and the engine cruise thrust requirement is used as the optimization constraint. Other constraints include no overheating before the engine turbine, flow balance of each engine component, power balance, etc.

[0054] 5) According to the above four steps, the variable topology architecture design optimization based on genetic algorithm can be carried out. The design optimization results show that the maximum aircraft airtime increment is -31.30%, which is a certain improvement compared with -35.53% before the architecture design optimization. The optimization results and the comparison with the architecture design before optimization are shown in Table 1.

[0055] Table 1 Comparison of results before and after optimization

[0056]

[0057] As shown in Table 1, after the engine architecture design and architecture optimization, the aircraft's cruising fuel consumption rate has decreased, and the application of the engine architecture has led to an increase in engine mass. The results before and after the architecture design optimization are compared. Figure 3 However, after calculation, the increment of the aircraft's airborne time is improved, indicating that the hydrogen turbine engine variable topology architecture design optimization method based on genetic algorithm provided by the present invention effectively improves the performance of the hydrogen turbine engine and reduces the mass compensation brought by the hydrogen turbine engine.

Claims

1. A method for optimizing a variable topology architecture of a hydrogen turbine engine based on a genetic algorithm, characterized in that: The following steps are involved: 1) Establish a benchmark hydrogen turbine engine; based on the traditional fuel aircraft engine, clarify the thrust requirements of the engine in each flight segment, convert it into a hydrogen turbine engine that meets the requirements, and determine its hydrogen fuel consumption; 2) Variable topology architecture design: Apply various unconventional engine architectures to the benchmark hydrogen turbine engine, so that the hydrogen fuel exchanges heat with the airflow at different positions in the engine, realize flexible combination of different architectures and flexible change of heat exchange capacity of the same architecture, simulate the actual situation when different architectures are applied to hydrogen turbine engines at the same time, and establish a variable topology architecture; 3) Establish optimization goals; in order to minimize the mass compensation effect of hydrogen fuel, find an architecture solution that minimizes the fuel consumption of hydrogen turbine engines while meeting the thrust requirements of the engine; 4) Establish optimization variables and optimization constraints; The optimization variables should be established to achieve the change of engine fuel consumption and the change of heat exchange of each architecture. The value range of each optimization variable should be determined according to the actual situation, and the engine thrust demand, no overheating before the engine turbine, and the balance conditions of each engine component should be selected as optimization constraints; 5) Implement optimization and obtain optimization results; Based on the above 4 steps, a genetic algorithm is used for optimization to calculate the maximum increment of the aircraft's maximum airborne time when equipped with a hydrogen turbine engine, and based on the values ​​of the optimization variables at this time, a hydrogen turbine engine architecture solution that minimizes the aircraft's mass compensation is obtained.

2. The method for optimizing the variable topology architecture of a hydrogen turbine engine based on a genetic algorithm according to claim 1, characterized in that: In step 3), as the fuel consumption reduction effect of the engine architecture increases, the heat exchange between the hydrogen fuel and the internal airflow of the engine in the architecture increases, resulting in an increase in the quality of the heat exchanger and an increase in the quality compensation. Under the condition that the maximum take-off weight remains unchanged, the increment of the maximum airtime when the aircraft is equipped with a hydrogen turbine engine compared with that of a traditional aircraft is calculated, and the quality compensation brought about by the application of various architectures of the hydrogen turbine engine is evaluated. A large increment of the airtime indicates a low quality compensation; a small increment of the airtime indicates a high quality compensation. The specific calculation formula for the increment of the airtime is as follows: Wherein, Δt represents the increment of the airborne time, which is used as an indicator to evaluate the mass compensation brought by the hydrogen turbine engine to the aircraft; t hydrogen Indicates the airborne time of an aircraft equipped with a hydrogen turbine engine; t traditional Indicates the time a traditional aircraft stays in the air; M f,traditional Indicates the maximum fuel mass that a traditional aircraft can carry; M h eat exch anger represents the increased mass of the heat exchanger after applying various architectures to the hydrogen turbine engine; α represents the hydrogen storage mass fraction; θ cruise Indicates the proportion of engine cruising fuel consumption to total fuel consumption; W f,h ydrogen,cruise represents the hydrogen fuel flow rate under the cruise condition of the hydrogen turbine engine; t remaining legs It represents the time the aircraft stays in the air for the rest of the flight except the cruising phase. The final optimization goal is to maximize the increase in the maximum time the aircraft can stay in the air when equipped with a hydrogen turbine engine compared with that of a traditional aircraft.

3. The method for optimizing the variable topology architecture of a hydrogen turbine engine based on a genetic algorithm according to claim 1, characterized in that: In step 4), when the optimization variables are changed, the engine thrust must always be maintained to meet the design requirements. The calculation formula is as follows: q mg V5-q ma V0+(p5-p0)A5≥T Baseline In the formula, the right side of the inequality is T Baseline represents the thrust requirement of the baseline engine; The left side of the inequality is the engine thrust calculation formula, where q mg represents the gas flow rate in the engine, q ma represents the air flow entering the engine, V5 and V0 represent the air flow velocity at the engine tail nozzle outlet and the engine flight speed respectively, p5 and p0 represent the engine tail nozzle outlet pressure and the ambient pressure respectively, and A5 represents the engine tail nozzle outlet area; The engine turbine does not overheat: T4≤T 4,max Where T4 represents the actual temperature before the engine turbine, T 4,max Indicates the maximum turbine inlet temperature determined by the engine turbine material; The gas flow through the turbine and the air flow through the compressor in the engine remain continuous: q mg =q ma -q ma,col +q mf In the formula, q mg is the gas flow rate through the turbine in the engine, q ma represents the air flow rate entering the engine, q ma,col represents the amount of cooling air drawn from the compressor, q mf Indicates the fuel flow rate entering the combustion chamber; Compressor and turbine power balance in the engine: q ma W c =q mg W t η m Where W c Indicates the output power of the compressor, W t represents the turbine power, η m It indicates the energy transfer efficiency when the turbine drives the compressor to rotate.

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