Method for fully pre-cooling intake air of hypersonic engine

Abstract

The invention belongs to the field of hypersonic engine design, and particularly relates to a hypersonic engine inlet air sufficient precooling method which is characterized in that a series heat exchanger is arranged to be connected with a fuel oil distribution control device, the series heat exchanger comprises a front precooler and a rear precooler, the front precooler is connected with a temporary storage device, and the rear precooler is connected with a fuel oil control system; system design requirements are obtained, and design parameters of a front precooler and a rear precooler are determined; the fuel distribution control device obtains fuel flow and air inflow in real time, distributes the fuel flow of the front precooler and the fuel flow of the rear precooler according to the fuel flow, and conveys the distributed fuel flow into the front precooler and the rear precooler respectively. Through the fuel oil distribution control device, additional fuel oil is used for providing enough cooling capacity, meanwhile, the air inlet precooling heat exchanger is subjected to multi-module design, and the contradiction that the heat exchange capacity needed by air inlet temperature drop is continuously increased along with the increase of the Mach number of the aircraft and the cooling capacity provided by the fuel oil cannot be matched is solved.

Description

Technical Field

[0001] This application belongs to the field of hypersonic engine design, and specifically relates to a method for sufficient pre-cooling of the intake air of a hypersonic engine. Background Technology

[0002] When a high-speed aircraft reaches Mach 3, the stagnation temperature of the incoming air can reach 600K (approximately 330℃) due to the high speed. At this point, the intake air temperature of the combined-power turbine engine is too high, causing a sharp decrease in engine performance and rendering it unable to provide thrust. To ensure the turbine can still operate effectively under these high intake air temperatures, an intake pre-cooling heat exchanger is typically used at the inlet of the high-speed turbine. This exchanger uses fuel or other cooling media to cool the engine intake air, reducing the temperature to a suitable level and ensuring normal engine operation.

[0003] As the flight envelope of high-speed aircraft continuously expands, the engine intake air temperature also increases, significantly increasing the heat that the intake precooling heat exchanger needs to remove. To meet the ever-increasing demand for intake air temperature reduction, more cooling medium (fuel) must be used to provide the cooling capacity. The engine intake precooling system is generally coupled with the fuel system. Through the regulation of the fuel system, the fuel exchanges heat with the intake air through the precooling heat exchanger before entering the combustion chamber, cooling the intake air. The fuel itself then enters the combustion chamber for combustion after its temperature rises, which also helps improve combustion performance.

[0004] Opinions on Existing Technical Solutions for Intake Precooling Heat Exchangers and Fuel Systems Figure 1 The cooling medium, fuel, in the precooling heat exchanger is regulated by the fuel system. After exchanging heat with the high-temperature air at the engine's main inlet, it enters the engine's main combustion chamber for combustion. The fuel flow rate involved in engine combustion is metered. As the flight Mach number increases and the intake air temperature rises, if the fuel flow rate required by the precooling heat exchanger to cool the intake air exceeds the fuel flow rate required for engine combustion, the precooling heat exchanger will not be able to obtain sufficient cooling capacity. This will prevent the engine inlet air temperature from decreasing to the temperature required for normal engine operation, leading to a decrease in engine performance and insufficient power to provide the aircraft, directly affecting the aircraft's operating envelope.

[0005] Therefore, how to achieve sufficient cooling of the intake air during turbine operation through a pre-cooling heat exchanger is a problem that needs to be solved. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a method for adequately pre-cooling the intake air of a hypersonic engine, thereby resolving the problem in the prior art where the fuel supplied by the fuel system cannot achieve the required adequate cooling of the intake air for turbine engines through a pre-cooling heat exchanger.

[0007] The technical solution of this application is: a method for sufficient pre-cooling of the intake air of a hypersonic engine, comprising:

[0008] A series heat exchanger is set up and connected to the fuel distribution control device. The series heat exchanger includes a pre-cooler and a post-cooler. The pre-cooler is connected to the temporary storage device and the post-cooler is connected to the fuel control system.

[0009] Obtain system design requirements, determine the heat dissipation requirements of fuel intake air, and determine the design parameters of the pre-cooler and post-cooler;

[0010] The fuel distribution control device acquires fuel flow and intake air volume in real time, distributes fuel flow to the pre-cooler and post-cooler according to the fuel flow, and delivers the distributed fuel flow to the pre-cooler and post-cooler respectively.

[0011] Preferably, the fuel distribution control device includes a data acquisition module, a flow calculation module, and a control module. The data acquisition module collects the engine intake Mach number, intake temperature, fuel system supply flow rate, and precooling heat exchanger inlet and outlet temperature parameters in real time, and sends them to the flow calculation module.

[0012] The flow calculation module receives data collected by the data acquisition module, calculates the total heat dissipation required for intake air cooling, and obtains additional fuel; based on the total heat dissipation and the fuel system supply flow, it determines the supplementary flow requirement of additional fuel and obtains metered fuel; and sends the additional fuel and metered fuel to the control module.

[0013] The control module controls the additional fuel to flow through the pre-cooler for heat exchange and then be introduced into the temporary fuel storage device. At the same time, it controls the metered fuel to flow through the post-cooler for heat exchange according to the engine combustion requirements and then be introduced into the combustion chamber.

[0014] Preferably, the control module adopts a dual-loop closed-loop control mode:

[0015] The first circuit is for metered fuel. It uses the engine combustion demand flow rate as the set value and calculates the metered fuel quantity under the current engine operating conditions by adjusting the opening of the metered fuel valve.

[0016] The second loop uses the target intake air cooling temperature as the set value and dynamically calculates the required temperature of the turbine intake air and the additional fuel after the intake air has been pre-cooled in two stages by adjusting the opening of the additional fuel valve.

[0017] Preferably, the flow calculation module first calculates the total heat dissipation of the intake cooling system according to the cooling demand calculation algorithm, which is:

[0018] Q 总 =c×m×ΔT;

[0019] Q 总ΔT represents the total heat dissipation of the intake air cooling, c represents the specific heat capacity of air, m represents the intake air mass flow rate, and ΔT represents the target temperature difference for intake air pre-cooling.

[0020] Then, based on the measured fuel cooling capacity Q 计 Calculate the additional fuel flow rate m 附 ,for:

[0021] Q 计 =c 燃 ×m 计 ×ΔT 燃 , where c 燃 For the specific heat capacity of fuel oil, m 计 To measure fuel flow rate, ΔTfuel is the allowable temperature rise of the fuel being measured;

[0022] matta = Q 附 / (c 燃 ×ΔT 燃附 ), where ΔT 燃附 Allowed temperature rise for additional fuel.

[0023] Preferably, the traffic calculation module further includes a dynamic traffic matching algorithm, which is:

[0024] Real-time acquisition and monitoring of engine operating data; when the intake Mach number increases, causing Q... 总 When the pressure increases, the opening degree of the auxiliary fuel valve is corrected through a PID control algorithm to control m. 附 Follow Q 附 Adjustments are made in real time to reflect changes, while maintaining the metered fuel flow rate m. 计 The difference between the upper and lower values ​​remains within a certain range.

[0025] Preferably, the control module is also equipped with a fault redundancy function: when a fault is detected in the auxiliary fuel circuit or the pre-cooler, the control module automatically issues an alarm signal and switches to emergency control mode to stop the auxiliary fuel circuit or the pre-cooler from working.

[0026] The method for sufficient pre-cooling of the intake air of the hypersonic engine in this application has the following advantages:

[0027] By using a fuel distribution control device, additional fuel is used to provide sufficient cooling capacity. At the same time, the intake precooling heat exchanger is designed in multiple modules, which solves the contradiction that the heat exchange required for the intake air temperature drop increases with the increase of the aircraft's Mach number and the cooling capacity that the fuel can provide cannot match. This ensures that the airflow temperature is reduced to a suitable level to meet the turbine intake air precooling requirements, and also ensures that the engine fuel control and supply system is not affected by the precooling system. Attached Figure Description

[0028] Figure 1 Schematic diagram of an existing intake precooling system;

[0029] Figure 2 This is a schematic diagram of the multi-module heat exchanger of this application. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0031] The first aspect of this application provides a method for sufficient pre-cooling of the intake air of a hypersonic engine, specifically including the following steps:

[0032] Step S100, as follows Figure 2 A series heat exchanger is set up and connected to the fuel distribution control device. The series heat exchanger includes a pre-cooler and a post-cooler. The pre-cooler is connected to the temporary storage device, and the post-cooler is connected to the fuel control system.

[0033] The fuel distribution control device includes a data acquisition module, a flow calculation module, and a control module. The data acquisition module collects the engine intake Mach number, intake temperature, fuel system supply flow rate, and inlet and outlet temperature parameters of the precooling heat exchanger in real time, and sends them to the flow calculation module.

[0034] The flow calculation module receives data collected by the data acquisition module, calculates the total heat dissipation required for intake air cooling, and obtains the additional fuel; based on the total heat dissipation and the fuel system supply flow, it determines the supplementary flow requirement of the additional fuel and obtains the metered fuel; and sends the additional fuel and the metered fuel to the control module.

[0035] The control module controls the auxiliary fuel to flow through the pre-cooler for heat exchange and then into the temporary fuel storage device. At the same time, it controls the metered fuel to flow through the post-cooler for heat exchange and then into the combustion chamber according to the engine combustion demand.

[0036] The above design achieves a closed-loop operation of "data acquisition - flow calculation - precise control". Each module has a clear division of labor and works together to improve the automation level and control accuracy of fuel distribution control.

[0037] Step S200: Obtain system design requirements, determine the heat dissipation requirements of fuel intake air, and determine the design parameters of the pre-cooler and post-cooler.

[0038] Preferably, the control module adopts a dual-loop closed-loop control mode:

[0039] The first circuit is for metered fuel. It uses the engine combustion demand flow rate as the set value and calculates the metered fuel quantity under the current engine operating conditions by adjusting the opening of the metered fuel valve.

[0040] The second loop uses the target intake air cooling temperature as the set value and dynamically calculates the required temperature of the turbine intake air and the additional fuel after the intake air has been pre-cooled in two stages by adjusting the opening of the additional fuel valve.

[0041] Preferably, the control module is also equipped with a fault redundancy function: when a fault is detected in the auxiliary fuel circuit or the pre-cooler, the control module automatically issues an alarm signal and switches to emergency control mode to stop the auxiliary fuel circuit or the pre-cooler from working.

[0042] Separate control logics were established for metered fuel and auxiliary fuel, enabling independent regulation and coordinated operation of the two fuel lines. The first loop ensures that the metered fuel flow rate is stably matched to the engine combustion conditions, preventing fluctuations in fuel flow from affecting engine combustion efficiency; the second loop dynamically compensates for insufficient cooling, ensuring that the intake air temperature meets the turbine's intake requirements.

[0043] In step S300, the fuel distribution control device acquires the fuel flow rate and intake air volume in real time, distributes the fuel flow rate of the pre-cooler and the post-cooler according to the fuel flow rate, and delivers the distributed fuel flow rate to the pre-cooler and the post-cooler respectively.

[0044] Preferably, the flow calculation module first calculates the total heat dissipation of the intake cooling system according to the cooling demand calculation algorithm, which is:

[0045] Q 总 =c×m×ΔT;

[0046] Q 总 ΔT represents the total heat dissipation of the intake air cooling, c represents the specific heat capacity of air, m represents the intake air mass flow rate, and ΔT represents the target temperature difference for intake air pre-cooling.

[0047] Then, based on the measured fuel cooling capacity Q 计 Calculate the additional fuel flow rate m 附 ,for:

[0048] Q 计 =c 燃 ×m 计 ×ΔT 燃 , where c 燃 For the specific heat capacity of fuel oil, m 计To measure fuel flow rate, ΔTfuel is the allowable temperature rise of the fuel being measured;

[0049] matta = Q 附 / (c 燃 ×ΔT 燃附 ), where ΔT 燃附 Allowed temperature rise for additional fuel.

[0050] The traffic calculation module also includes a dynamic traffic matching algorithm, which is:

[0051] Real-time acquisition and monitoring of engine operating data; when the intake Mach number increases, causing Q... 总 When the pressure increases, the opening degree of the auxiliary fuel valve is corrected through a PID control algorithm to control m. 附 Follow Q 附 Adjustments are made in real time to reflect changes, while maintaining the metered fuel flow rate m. 计 The difference between the upper and lower values ​​remains within a certain range.

[0052] The flow dynamic matching algorithm enables real-time response to changes in engine operating conditions. When the intake Mach number increases, leading to an increase in total heat dissipation, the PID control algorithm quickly corrects the opening of the auxiliary fuel valve, so that the auxiliary fuel flow follows the changes in cooling demand in real time, ensuring that cooling supply and demand are synchronized and avoiding cooling lag caused by changes in operating conditions.

[0053] The overall control principle is as follows:

[0054] The intake precooling heat exchanger consists of two heat exchangers connected in series. The first precooler uses a portion of the fuel to exchange heat with the incoming intake air, while the second precooler performs secondary precooling according to the fuel flow rate required by the engine, ensuring that the intake air temperature entering the turbine meets the engine performance requirements. The design of the precooling heat exchanger is based on the intake air heat dissipation requirements, ensuring that it can remove heat from the incoming air and adequately cool the intake air. Furthermore, based on the design scheme of the precooling heat exchanger, the flow matching relationship between metered fuel and auxiliary fuel at various states within the engine's operating range is determined, i.e., the fuel distribution control law of the precooling system.

[0055] By constructing a core structure of "series heat exchanger + fuel distribution control device", the corresponding connection relationship between the pre-cooler and temporary storage device, and between the post-cooler and fuel control system is clarified, forming a complete technical architecture of "dual-path fuel cooling + staged pre-cooling". This solves the problem of insufficient cooling capacity in the traditional single fuel circuit from a structural perspective, and provides a basic guarantee for sufficient pre-cooling of intake air.

[0056] In summary, this application has the following advantages:

[0057] By using a fuel distribution control device, additional fuel is used to provide sufficient cooling capacity. At the same time, the intake precooling heat exchanger is designed in multiple modules, which solves the contradiction that the heat exchange required for the intake air temperature drop increases with the increase of the aircraft's Mach number and the cooling capacity that the fuel can provide cannot match. This ensures that the airflow temperature is reduced to a suitable level to meet the turbine intake air precooling requirements, and also ensures that the engine fuel control and supply system is not affected by the precooling system.

[0058] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for fully pre-cooling the intake air of a hypersonic engine, characterized in that, include: A series heat exchanger is set up and connected to the fuel distribution control device. The series heat exchanger includes a pre-cooler and a post-cooler. The pre-cooler is connected to the temporary storage device and the post-cooler is connected to the fuel control system. Obtain system design requirements, determine the heat dissipation requirements of fuel intake air, and determine the design parameters of the pre-cooler and post-cooler; The fuel distribution control device acquires fuel flow and intake air volume in real time, distributes fuel flow to the pre-cooler and post-cooler according to the fuel flow, and delivers the distributed fuel flow to the pre-cooler and post-cooler respectively.

2. The method for sufficient pre-cooling of the intake air of a hypersonic engine as described in claim 1, characterized in that, The fuel distribution control device includes a data acquisition module, a flow calculation module, and a control module. The data acquisition module collects the engine intake Mach number, intake temperature, fuel system supply flow rate, and precooling heat exchanger inlet and outlet temperature parameters in real time and sends them to the flow calculation module. The flow calculation module receives data collected by the data acquisition module, calculates the total heat dissipation required for intake air cooling, and obtains additional fuel; based on the total heat dissipation and the fuel system supply flow, it determines the supplementary flow requirement of additional fuel and obtains metered fuel; and sends the additional fuel and metered fuel to the control module. The control module controls the additional fuel to flow through the pre-cooler for heat exchange and then be introduced into the temporary fuel storage device. At the same time, it controls the metered fuel to flow through the post-cooler for heat exchange according to the engine combustion demand and then be introduced into the combustion chamber.

3. The method for sufficient pre-cooling of the intake air of a hypersonic engine as described in claim 2, characterized in that, The control module adopts a dual-loop closed-loop control mode: The first circuit is for metered fuel. It uses the engine combustion demand flow rate as the set value and calculates the metered fuel quantity under the current engine operating conditions by adjusting the opening of the metered fuel valve. The second loop uses the target intake air cooling temperature as the set value and dynamically calculates the required temperature of the turbine intake air and the additional fuel after the intake air has been pre-cooled in two stages by adjusting the opening of the additional fuel valve.

4. The method for sufficient pre-cooling of the intake air of a hypersonic engine as described in claim 3, characterized in that, The flow calculation module first calculates the total heat dissipation of the intake cooling system according to the cooling demand calculation algorithm, which is: Q 总 =c×m×ΔT; Q 总 ΔT represents the total heat dissipation of the intake air cooling, c represents the specific heat capacity of air, m represents the intake air mass flow rate, and ΔT represents the target temperature difference for intake air pre-cooling. Then, based on the measured fuel cooling capacity Q 计 Calculate the additional fuel flow rate m 附 ,for: Q 计 =c 燃 ×m 计 ×ΔT 燃 , where c 燃 For the specific heat capacity of fuel oil, m 计 To measure fuel flow rate, ΔTfuel is the allowable temperature rise of the fuel being measured; matta = Q 附 / (c 燃 ×ΔT 燃附 ), where ΔT 燃附 Allowed temperature rise for additional fuel.

5. The method for sufficient pre-cooling of the intake air of a hypersonic engine as described in claim 4, characterized in that, The traffic calculation module also includes a dynamic traffic matching algorithm, which is: Real-time acquisition and monitoring of engine operating data; when the intake Mach number increases, causing Q... 总 When the pressure increases, the opening degree of the auxiliary fuel valve is corrected through a PID control algorithm to control m. 附 Follow Q 附 Adjustments are made in real time to reflect changes, while maintaining the metered fuel flow rate m. 计 The difference between the upper and lower values ​​remains within a certain range.

6. The method for sufficient pre-cooling of the intake air of a hypersonic engine as described in claim 3, characterized in that, The control module is also equipped with a fault redundancy function: when a fault is detected in the auxiliary fuel circuit or the pre-cooler, the control module automatically issues an alarm signal and switches to emergency control mode to stop the auxiliary fuel circuit or the pre-cooler from working.

Images