A temperature control system for a regeneratively cooled ramjet engine

Abstract

The present invention belongs to the technical field of scramjet engine control, and specifically is a regenerative cooling ramjet engine temperature control system, which includes a novel cooling oil supply system with an oil drain valve as the core and an engine thrust and temperature decoupling control method, and the temperature control system improves the cooling capacity of the ramjet engine, broadens the working boundary of the engine, and ensures that the temperature is controllable and the engine thrust is maintained constant during the temperature control process.

Description

Technical Field

[0001] The present invention belongs to the technical field of scramjet engine control, and more specifically, relates to a regenerative cooling ramjet engine temperature control system with a temperature control system and a thrust temperature decoupling control method as the core. Background Art

[0002] As a power device for hypersonic vehicles, scramjet engines have the characteristics of high specific impulse under flight conditions above Mach 6, which has obvious advantages over other power cycle modes. Therefore, scramjet engines have become one of the core technologies of hypersonic vehicles, and the research on various mechanisms and application technologies of scramjet engines has become a hot topic in recent years.

[0003] When the scramjet engine operates at a high Mach number, the operating temperature of the combustion chamber is very high due to the increase in the total temperature of the incoming flow and the heat released by the engine combustion. Long-term operation of the engine is prone to cause wall ablation, increasing the risk of burning the engine. Regenerative cooling is a preferred solution for engine thermal protection. The engine wall is cooled by passing cold fuel through the cooling channel on the engine wall.

[0004] In recent years, research has been conducted at home and abroad on the regenerative cooling and over-temperature control of ramjet engines. The current regenerative cooling system adopts a solution that pumps the cold fuel from the fuel tank into the cooling channel distributed on the engine wall through a fuel pump. The cold fuel absorbs heat and becomes hot fuel, and finally is injected into the engine through an injector to participate in combustion. When the engine overheats, the main solution is to increase the fuel flow rate pumped into the cooling channel, and finally inject all the cooling fuel into the engine combustion chamber. The existing regenerative cooling system solution has certain shortcomings, mainly reflected in: the hot fuel passing through the cooling channel is all injected into the engine combustion chamber, which places high requirements on the initial matching design of the engine, and the cooling capacity of the cooling system is weak, which cannot meet the requirements of the engine's wide speed range cruising. In addition, when overheating occurs, the existing over-temperature control system adopts the method of increasing the fuel flow rate of the cooling channel. Since the fuel is finally injected into the combustion chamber, the increase in fuel flow rate will lead to an increase in the thrust of the engine, making the aircraft fly faster and faster, and the heat load of the engine increases, which may eventually lead to the failure of the engine over-temperature control. Therefore, it is necessary to design a new engine cooling system solution and propose a temperature control method to keep the engine thrust constant when overheating. Summary of the invention

[0005] In view of the defects in the prior art, the present invention provides a temperature control system and a control method suitable for a regeneratively cooled ramjet engine, and meets the special use requirements of the regeneratively cooled ramjet engine.

[0006] To achieve the above-mentioned purpose of the invention, the technical solution of the present invention is as follows:

[0007] A regenerative cooling ramjet engine temperature control system, comprising an engine cooling oil supply system and a control unit;

[0008] Engine cooling oil supply system: A drain branch is designed in the cooling system of the regenerative cooling engine. The drain valve recovers part of the fuel that has passed through the cooling channel through the cooler and then to the fuel tank. The engine temperature can be controlled in real time by adjusting the output flow of the fuel pump and the opening of the drain valve.

[0009] The cooling oil supply system comprises an oil tank, a first filter, a fuel pump, a second filter, a first flow meter, an oil drain valve, a cooler, a waste oil recovery tank, an oil supply valve, a second flow meter and an oil injection support plate;

[0010] The fuel tank is connected to the first filter, the fuel pump inlet is connected to the first filter, the fuel pump outlet is connected to the second filter, the second filter is connected to the intake passage via a first flow meter, the first flow meter is located before the inlet of the engine cooling channel, and measures the fuel flow entering the engine cooling channel in real time;

[0011] When the fuel flows out of the cooling channel of the tail nozzle, it is divided into two branches, namely the fuel supply branch and the drain branch. One branch of the fuel passes through the fuel supply valve and the second flow meter and then is sprayed into the engine combustion chamber through the fuel injection branch plate to participate in combustion. The second flow meter measures the fuel flow participating in combustion in real time. The other branch of the fuel passes through the drain valve and the cooler and then goes to the waste oil recovery tank.

[0012] Control unit: includes engine thrust control system and engine temperature control system, adopts engine thrust and temperature decoupling control method to realize thrust and temperature control of regenerative cooling ramjet engine, fuel pump is the actuator of engine thrust control system, drain valve is the actuator of engine temperature control system, realizes constant fuel flow into engine combustion chamber, and at the same time, cold fuel flow into combustion chamber cooling channel is regulated according to temperature conditions.

[0013] As a preferred embodiment, the design method of the control unit includes the following steps:

[0014] (a) Construct the input matrix, output matrix and transfer function matrix of the regenerative cooling ramjet engine cooling system;

[0015] (b) Calculate the decoupling matrix of the engine thrust control loop and the temperature control loop;

[0016] (c) Design the thrust control system and temperature control system of the regenerative cold ramjet engine based on the deviation correction theory.

[0017] As a preferred method, the design method of the engine cooling and fuel supply system is: the fuel pump first pumps the cold fuel in the fuel tank into the cooling flow channel on the engine wall to turn it into hot fuel, and then the hot fuel is divided into two paths, one path of fuel passes through the fuel supply valve into the engine combustion chamber to participate in combustion, and the other path of fuel is controlled by the proportional valve to flow through the cooler to the recovery tank. The drain valve is selected as a proportional valve, and the oil leakage flow rate is controlled by changing the size of the valve flow cross-sectional area.

[0018] As a preferred method, the engine thrust and temperature decoupling control method is: decoupling control introduces a decoupling controller to decouple the thrust and temperature control objects of the regenerative cooling ramjet engine, so that the thrust and temperature are independently controlled without affecting each other.

[0019] As a preferred method, decouple the controlled object transfer function matrix is a reversible matrix, and the decoupling matrix is , is the objective function matrix, S is a complex variable; the thrust controller and temperature controller are designed using correction theory and control algorithm based on target deviation;

[0020] Regeneratively cooled engine thrust and temperature decoupling system, where is the system input matrix, is the system thrust input, is the system temperature input, is the system output matrix, is the engine thrust, T is the oil temperature of the regenerative cooling system, is the transfer function matrix of the regenerative cooling ramjet system, expressed as:

[0021] ;in, g 11 , g 12 , g 21 and g 22 is the value in the transfer function matrix;

[0022] The target matrix obtained by system decoupling is:

[0023] ;

[0024] is a diagonal matrix, retaining The elements on the main diagonal of , and all other elements in the matrix are zero;

[0025] Assume that the transfer function matrix of the decoupled controlled object is is a reversible matrix, and the decoupling matrix is:

[0026] ;

[0027] is the control matrix of the system thrust and temperature, which includes the thrust controller and temperature controller .

[0028] As a preferred method, the thrust controller The design process is as follows:

[0029] The thrust controller is designed based on error control theory. The design process is as follows:

[0030] ;

[0031] In the formula, is the system thrust input, is the engine thrust, is the thrust error, k p1 , k i1 and k d1 They are the proportional coefficient, integral coefficient and differential coefficient of the thrust controller respectively.

[0032] As a preferred method, the temperature controller The design process is as follows:

[0033] The temperature controller is also designed using error control theory. The design process is as follows:

[0034] ;

[0035] In the formula, is the system temperature input, T is the oil temperature of the regenerative cooling system, is the temperature error, k p2 , k i2 and k d2 They are the proportional coefficient, integral coefficient and differential coefficient of the thrust controller respectively.

[0036] The working principle of the present invention is as follows: Figure 1As shown, the cooling system is based on the oil leakage proportional valve. The fuel pump of the regenerative cooling ramjet engine fuel supply system pumps the cold fuel in the fuel tank into the cooling flow channel on the engine wall to turn it into hot fuel. Then the hot fuel is divided into two paths. One path of fuel passes through the fuel supply valve and enters the engine combustion chamber to participate in combustion. The other path of fuel is controlled by the oil leakage proportional valve and flows through the cooler to the recovery tank. The oil leakage valve is selected as a proportional valve, and the oil leakage flow rate is controlled by changing the size of the valve flow cross-sectional area. After the oil leakage valve is introduced into the cooling oil supply system, the fuel used for cooling will not completely enter the combustion chamber. By controlling the fuel pump flow and the opening of the oil leakage valve, the fuel flow entering the engine combustion chamber can be constant, and the cold fuel flow entering the cooling flow channel of the combustion chamber can be regulated. This cooling system not only achieves the constant engine thrust during temperature control, but also broadens the working range of the engine cooling system.

[0037] The beneficial effects of the present invention compared with the prior art are:

[0038] The present invention adopts a regenerative cooling system oil supply scheme based on an oil drain valve, and designs a decoupling control method for engine thrust and temperature, which can achieve a constant fuel flow rate entering the engine combustion chamber, while the cold fuel flow rate entering the combustion chamber cooling flow channel can be regulated according to the temperature conditions. This cooling system not only achieves constant engine thrust during temperature control, but also broadens the working range of the engine cooling system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the oil supply system for the regenerative cooling ramjet engine of the present invention.

[0040] Figure 2 This is a diagram of the thrust and temperature decoupling control structure of the regenerative cooling engine of the present invention.

[0041] Figure 3 This is a block diagram of the thrust and temperature decoupling system of the regenerative cooling engine of the present invention.

[0042] 1-fuel tank, 2-first filter, 3-fuel pump, 4-second filter, 5-first flow meter, 6-oil drain valve, 7-cooler, 8-waste oil recovery tank, 9-fuel supply valve, 10-second flow meter, 11-injection support plate, 12-intake duct, 13-combustion chamber, 14-tail nozzle. DETAILED DESCRIPTION

[0043] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0044] like Figure 1 As shown, the embodiment provides a regenerative cooling ramjet engine temperature control system, including an engine cooling oil supply system and a control unit;

[0045] Engine cooling oil supply system: A drain branch is designed in the cooling system of the regenerative cooling engine. The drain valve recovers part of the fuel flowing through the cooling channel through the cooler and then into the fuel tank. The engine temperature is controlled in real time by adjusting the output flow of the fuel pump 3 and the opening of the drain valve 6.

[0046] The cooling oil supply system comprises an oil tank 1, a first filter 2, a fuel pump 3, a second filter 4, a first flow meter 5, an oil drain valve 6, a cooler 7, a waste oil recovery tank 8, an oil supply valve 9, a second flow meter 10 and an oil injection support plate 11;

[0047] The fuel tank 1 is connected to the first filter 2, the inlet of the fuel pump 3 is connected to the first filter 2, the outlet of the fuel pump 3 is connected to the second filter 4, the second filter 4 is connected to the intake passage 12 via the first flow meter 5, the first flow meter 5 is located in front of the inlet of the engine cooling channel, and measures the fuel flow entering the engine cooling channel in real time;

[0048] When the fuel flows out from the cooling channel of the tail nozzle 14, it is divided into two branches, namely the fuel supply branch and the leakage branch. One branch of the fuel passes through the fuel supply valve 9 and the second flow meter 10 and is sprayed into the engine combustion chamber 13 through the fuel injection branch plate 11 to participate in combustion. The fuel injection branch plate 11 connects the second flow meter 10 and the fuel supply branch where the fuel supply valve 9 is located. The second flow meter 10 measures the fuel flow participating in combustion in real time. The other branch of the fuel passes through the leakage valve 6 and the cooler 7 to the waste oil recovery tank 8; the waste oil recovery tank 8 is connected to the leakage branch where the leakage valve 6 and the cooler 7 are located.

[0049] Control unit: includes engine thrust control system and engine temperature control system, adopts engine thrust and temperature decoupling control method to realize thrust and temperature control of regenerative cooling ramjet engine, fuel pump is the actuator of engine thrust control system, drain valve is the actuator of engine temperature control system, realizes constant fuel flow into engine combustion chamber, and at the same time, cold fuel flow into combustion chamber cooling channel is regulated according to temperature conditions.

[0050] The design method of the control unit includes the following steps:

[0051] (a) Construct the input matrix, output matrix and transfer function matrix of the regenerative cooling ramjet engine cooling system;

[0052] (b) Calculate the decoupling matrix of the engine thrust control loop and the temperature control loop;

[0053] (c) Design the thrust control system and temperature control system of the regenerative cold ramjet engine based on the deviation correction theory.

[0054] The design method of the engine cooling fuel supply system is as follows: the fuel pump first pumps the cold fuel in the fuel tank into the cooling flow channel on the engine wall to turn it into hot fuel, and then the hot fuel is divided into two paths. One path of fuel passes through the fuel supply valve and enters the engine combustion chamber to participate in combustion, and the other path of fuel is controlled by the oil drain proportional valve to flow through the cooler and then to the recovery tank. The oil drain valve is selected as a proportional valve, and the oil drain flow rate is controlled by changing the size of the valve flow cross-sectional area.

[0055] The engine thrust and temperature decoupling control method is: decoupling control introduces a decoupling controller to decouple the thrust and temperature control objects of the regenerative cooling ramjet engine, so that the thrust and temperature are independently controlled without affecting each other.

[0056] Decoupled plant transfer function matrix is a reversible matrix, and the decoupling matrix is , is the objective function matrix, S is a complex variable; the thrust controller and temperature controller are designed using correction theory and control algorithm based on target deviation;

[0057] Regeneratively cooled engine thrust and temperature decoupling system, where is the system input matrix, is the system thrust input, is the system temperature input, is the system output matrix, is the engine thrust, T is the oil temperature of the regenerative cooling system, is the transfer function matrix of the regenerative cooling ramjet system, expressed as:

[0058] ;in, g 11 , g 12 , g 21 and g 22 is the value in the transfer function matrix;

[0059] The target matrix obtained by system decoupling is:

[0060] ;

[0061] is a diagonal matrix, retaining The elements on the main diagonal of , and all other elements in the matrix are zero;

[0062] Assume that the transfer function matrix of the decoupled controlled object is is a reversible matrix, and the decoupling matrix is:

[0063] ;

[0064] is the control matrix of the system thrust and temperature, which includes the thrust controller and temperature controller .

[0065] Thrust controller The design process is as follows:

[0066] The thrust controller is designed based on error control theory. The design process is as follows:

[0067] ;

[0068] In the formula, is the system thrust input, is the engine thrust, is the thrust error, k p1 , k i1 and k d1 They are the proportional coefficient, integral coefficient and differential coefficient of the thrust controller respectively.

[0069] Temperature Controller The design process is as follows:

[0070] The temperature controller is also designed using error control theory. The design process is as follows:

[0071] ;

[0072] In the formula, is the system temperature input, T is the oil temperature of the regenerative cooling system, is the temperature error, k p2 , k i2 and k d2 They are the proportional coefficient, integral coefficient and differential coefficient of the thrust controller respectively.

[0073] Figure 2 The thrust and temperature decoupling control structure diagram for the regenerative cooling engine is shown in Figure 1. r 1 and r 2 They are the expected value of thrust and the expected value of temperature respectively. The thrust controller and the temperature controller calculate the control quantities of temperature and thrust respectively. The decoupling controller decouples the coupled temperature system and thrust system. The two control quantities of temperature and thrust are coupled in the regenerative cooling engine system.

[0074] Figure 3 This is the control block diagram of the regenerative cooling engine thrust and temperature decoupling system. R(s) is the input matrix of the system, which contains r 1 and r 2 , C(s) is the controller matrix, which includes the thrust controller c 1 and c2 , after decoupling the matrix and the engine controlled object matrix, the output value is obtained Y(s) , that is, the actual temperature value and thrust value, and the output value is fed back to the input end through the feedback loop to participate in the error calculation.

[0075] According to the above steps, the engine temperature can be controlled within a wide range, while ensuring the constant engine thrust during the temperature control process.

[0076] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A regenerative cooling ramjet engine temperature control system, characterized in that: Including engine cooling and oil supply system and control unit; Engine cooling oil supply system: A drain branch is designed in the cooling system of the regenerative cooling engine, and a portion of the fuel flowing through the cooling channel is recovered into the fuel tank through the drain valve after passing through the cooler, and the engine temperature is controlled in real time by adjusting the output flow of the fuel pump (3) and the opening of the drain valve (6); The cooling oil supply system comprises an oil tank (1), a first filter (2), a fuel pump (3), a second filter (4), a first flow meter (5), an oil drain valve (6), a cooler (7), a waste oil recovery tank (8), an oil supply valve (9), a second flow meter (10) and an oil injection support plate (11); The fuel tank (1) is connected to the first filter (2), the inlet of the fuel pump (3) is connected to the first filter (2), the outlet of the fuel pump (3) is connected to the second filter (4), the second filter (4) is connected to the intake passage (12) via a first flow meter (5), the first flow meter (5) is located before the inlet of the engine cooling passage, and measures the fuel flow entering the engine cooling passage in real time; After the fuel flows out of the cooling channel of the tail nozzle (14), it is divided into two branches, namely, a fuel supply branch and a drain branch. One branch of the fuel passes through a fuel supply valve (9) and a second flow meter (10) and is then sprayed into an engine combustion chamber (13) through a fuel injection support plate (11) to participate in combustion. The second flow meter (10) measures the flow of the fuel participating in combustion in real time. The other branch of the fuel passes through a drain valve (6) and a cooler (7) and is then sent to a waste oil recovery tank (8). Control unit: includes engine thrust control system and engine temperature control system, adopts engine thrust and temperature decoupling control method to realize thrust and temperature control of regenerative cooling ramjet engine, fuel pump is the actuator of engine thrust control system, drain valve is the actuator of engine temperature control system, realizes constant fuel flow into engine combustion chamber, and at the same time, cold fuel flow into combustion chamber cooling channel is regulated according to temperature conditions.

2. The regenerative cooling ramjet engine temperature control system according to claim 1, characterized in that: The design method of the control unit includes the following steps: (a) Construct the input matrix, output matrix and transfer function matrix of the regenerative cooling ramjet engine cooling system; (b) Calculate the decoupling matrix of the engine thrust control loop and the temperature control loop; (c) Design the thrust control system and temperature control system of the regenerative cold ramjet engine based on the deviation correction theory.

3. The regenerative cooling ramjet engine temperature control system according to claim 1, characterized in that: The design method of the engine cooling fuel supply system is as follows: the fuel pump first pumps the cold fuel in the fuel tank into the cooling flow channel on the engine wall to turn it into hot fuel, and then the hot fuel is divided into two paths. One path of fuel passes through the fuel supply valve and enters the engine combustion chamber to participate in combustion, and the other path of fuel is controlled by the oil drain proportional valve to flow through the cooler and then to the recovery tank. The oil drain valve is selected as a proportional valve, and the oil drain flow rate is controlled by changing the size of the valve flow cross-sectional area.

4. The regenerative cooling ramjet engine temperature control system according to claim 1, characterized in that: The engine thrust and temperature decoupling control method is: decoupling control introduces a decoupling controller to decouple the thrust and temperature control objects of the regenerative cooling ramjet engine, so that the thrust and temperature are independently controlled without affecting each other.

5. The regenerative cooling ramjet engine temperature control system according to claim 4, characterized in that: Decoupled plant transfer function matrix is a reversible matrix, and the decoupling matrix is , is the objective function matrix, S is a complex variable; the thrust controller and temperature controller are designed using correction theory and control algorithm based on target deviation; Regeneratively cooled engine thrust and temperature decoupling system, where is the system input matrix, is the system thrust input, is the system temperature input, is the system output matrix, is the engine thrust, T is the oil temperature of the regenerative cooling system, is the transfer function matrix of the regenerative cooling ramjet system, expressed as: ;in, g 11 , g 12 , g 21 and g 22 is the value in the transfer function matrix; The target matrix obtained by system decoupling is: ; is a diagonal matrix, retaining The elements on the main diagonal of , and all other elements in the matrix are zero; Assume that the transfer function matrix of the decoupled controlled object is is a reversible matrix, and the decoupling matrix is: ; is the control matrix of the system thrust and temperature, which includes the thrust controller and temperature controller .

6. The regenerative cooling ramjet engine temperature control system according to claim 5, characterized in that: Thrust controller The design process is as follows: The thrust controller is designed based on error control theory. The design process is as follows: ; In the formula, is the system thrust input, is the engine thrust, is the thrust error, k p1 , k i1 and k d1 They are the proportional coefficient, integral coefficient and differential coefficient of the thrust controller respectively.

7. The regenerative cooling ramjet engine temperature control system according to claim 5, characterized in that: Temperature Controller The design process is as follows: The temperature controller is also designed using error control theory. The design process is as follows: ; In the formula, is the system temperature input, T is the oil temperature of the regenerative cooling system, is the temperature error, k p2 , k i2 and k d2 They are the proportional coefficient, integral coefficient and differential coefficient of the thrust controller respectively.

Images