阅读说明：本技术 一种火箭基组合循环发动机进气道的起动控制方法 (Starting control method for rocket-based combined cycle engine air inlet ) 是由 石磊 杨一言 赵国军 杨雪 魏祥庚 秦飞 何国强 于 2020-05-01 设计创作，主要内容包括：本发明提供一种火箭基组合循环发动机进气道的起动控制方法,判断燃烧室的室内压强是否大于第一压强阈值且小于或等于第二压强阈值,若是,则将降低内置火箭的质量流率,并减小二次燃料喷注量,以使燃烧室的室内压强降低,当燃烧室的室内压强进行降低至小于第一压强阈值时,将内置火箭的质量流率提高,并提高二次燃料喷注量,以使燃烧室内的室内压强提高并将燃烧室内的室内压强提高至第一压强阈值,通过改变内置火箭的工作状态,使内置火箭射流半径发生变化,从而调节进气道的实际等效内收缩比,同时燃烧室压力由于燃料流量减小而相应减小,也可以通过利用内置火箭高速射流对低能边界层的吹扫作用,以此来抑制进气道不起动。(The invention provides a starting control method of a rocket-based combined cycle engine air inlet, which judges whether the indoor pressure of a combustion chamber is greater than a first pressure threshold and less than or equal to a second pressure threshold, if so, reduces the mass flow rate of a built-in rocket, reduces the injection amount of secondary fuel to reduce the indoor pressure of the combustion chamber, improves the mass flow rate of the built-in rocket and improves the injection amount of the secondary fuel to improve the indoor pressure in the combustion chamber and improve the indoor pressure in the combustion chamber to the first pressure threshold when the indoor pressure of the combustion chamber is reduced to be less than the first pressure threshold, changes the working state of the built-in rocket to change the radius of the built-in jet so as to adjust the actual equivalent internal contraction ratio of the rocket, simultaneously reduces the pressure of the combustion chamber correspondingly due to the reduction of the fuel flow, and also can sweep a low-energy boundary layer by utilizing the built-in rocket with high-speed jet, thereby suppressing the intake duct from not starting.)

1. A starting control method of an air inlet channel of a rocket-based combined cycle engine is applied to the rocket-based combined engine and is characterized in that the rocket-based combined engine comprises the following steps: intake duct, isolation section, combustion chamber and built-in rocket, wherein:

the air inlet channel, the isolation section and the combustion chamber are sequentially connected, and air flow flows in from the air inlet channel, passes through the isolation section, works in the combustion chamber and then is discharged outwards from the tail end of the combustion chamber;

judging whether the indoor pressure of the combustion chamber is larger than a first pressure threshold and smaller than or equal to a second pressure threshold, if so, reducing the mass flow rate of the built-in rocket to 0.20kg/s, properly reducing the injection amount of secondary fuel to reduce the indoor pressure of the combustion chamber, and when the indoor pressure of the combustion chamber is reduced to be smaller than the first pressure threshold, increasing the mass flow rate of the built-in rocket to 0.30kg/s-0.35kg/s, and properly increasing the injection amount of secondary fuel to increase the indoor pressure of the combustion chamber and increase the indoor pressure of the combustion chamber to the first pressure threshold, wherein the first pressure threshold ranges from 0.130MPa to 0.140MPa, and the second pressure threshold ranges from 0.145MPa to 0.155 MPa.

2. A method of controlling starting of an inlet port of a rocket-based combined cycle engine as recited in claim 1, wherein the mass flow rate of said built-in rocket is reduced by reducing the amount of fuel and oxidant supplied to said built-in or case.

3. A method of controlling starting of an inlet port for a rocket-based combined cycle engine as recited in claim 1, wherein said inlet port is a mixed pressure inlet port.

4. A method of controlling starting of an intake port of a rocket-based combined cycle engine according to claim 1, wherein said built-in rocket is located at an outlet of said isolated section and is disposed at a side of said isolated section.

5. A method of controlling starting of an intake port of a rocket-based combined cycle engine according to claim 1, wherein said built-in rocket is a liquid fuel rocket.

Technical Field

The invention relates to the field of air-breathing combined propulsion systems, in particular to a rocket-based combined cycle engine.

Background

A Rocket-Based Combined Cycle (RBCC) engine organically integrates a Rocket engine with a high thrust-weight ratio and an air-breathing ramjet engine with a high specific impulse into the same runner, can be compatible with injection, sub-combustion, super-combustion and pure Rocket modes, and realizes high-performance work in a wide speed range and a large airspace. When designing an RBCC power system, researchers expect that the Mach number corresponding to an air inlet starting point and an engine injection/sub-combustion mode transition point is as low as possible, so that wide compatibility is obtained, and the overall performance of the engine is improved. When the air inlet is just started, the back pressure resistance of the air inlet is weak, in addition, the engine needs to finish mode transition as soon as possible, the working parameters and the state change violently, and the air inlet is easy to fall into an un-starting state due to strong disturbance of jet flow of a built-in rocket, pressure of a combustion chamber and the like. The normal work of the RBCC engine in a stamping mode can be seriously influenced by the fact that the air inlet channel is not started, so that the performance of the engine is greatly reduced, and even the flight mission fails. Aiming at the extreme condition that the air inlet is endangered to be not started due to some strong disturbance, a reasonable early warning mechanism is formulated, and the phenomenon that the air inlet is not started is found and effectively restrained in time, so that the engine is always in a normal and stable working state, and the method plays an important role in completing the whole flight task. Because the RBCC air inlet channel and the built-in rocket are closely coupled, how to change the working states of the air inlet channel and the whole RBCC engine by using a method for adjusting the state of the built-in rocket so as to inhibit the air inlet channel from not starting is a key technology for ensuring the normal operation of the RBCC engine.

At present, most publications mainly aim at the starting performance of the conventional supersonic air inlet. Since the conventional ramjet is not affected by the built-in rocket, the method for rapidly inhibiting the air inlet channel from not starting is mainly to rapidly reduce the fuel injection of a combustion chamber so as to reduce the pressure of the combustion chamber, adjust the flying posture of the aircraft and the like. However, considering the important influence of the rocket built in the RBCC engine on the state performance of the whole engine, the adjusting capacity of the existing method for adjusting by only reducing the pressure intensity of a combustion chamber is limited, the problem that an air inlet channel is not started when the rocket-based combined cycle engine works in a stamping mode can occur, if the air inlet channel is not started, the air capture amount is rapidly reduced, the normal work of the engine can be affected, and the overall performance of the engine is seriously weakened, wherein if the adjustable range is smaller by using modes of air inlet channel variable structure, fuel injection adjustment, flight attitude adjustment and the like, the requirement of rapid inhibition of the RBCC air inlet channel when the RBCC air inlet channel is not started in extreme condition early warning can not be flexibly met, and moreover, by adopting an unreasonable mode of changing the air inlet channel into a geometric mode, the problems of relatively serious mechanical sealing and high-temperature dynamic sealing can occur, or even more pneumatic adjustment means, leading to a considerable increase in the structural mass.

Therefore, how to effectively improve the regulation and control capability of inhibiting the air inlet from being not started by adjusting the state of the built-in rocket and matching with the flight attitude adjustment is a technical problem to be solved urgently by technical personnel in the field.

Disclosure of Invention

In order to achieve the above object, the present invention provides a method for controlling the start of an intake port of a rocket-based combined cycle engine, which is applied to a rocket-based combined engine, the rocket-based combined engine including: intake duct, isolation section, combustion chamber and built-in rocket, wherein:

the air inlet channel, the isolation section and the combustion chamber are sequentially connected, and air flow flows in from the air inlet channel, passes through the isolation section, works in the combustion chamber and then is discharged outwards from the tail end of the combustion chamber;

judging whether the indoor pressure of the combustion chamber is larger than a first pressure threshold and smaller than or equal to a second pressure threshold, if so, reducing the mass flow rate of the built-in rocket to 0.20kg/s, reducing the injection amount of secondary fuel to reduce the indoor pressure of the combustion chamber, and when the indoor pressure of the combustion chamber is reduced to be smaller than the first pressure threshold, increasing the mass flow rate of the built-in rocket to 0.30kg/s-0.35kg/s, and increasing the injection amount of secondary fuel to increase the indoor pressure of the combustion chamber and increase the indoor pressure of the combustion chamber to the first pressure threshold, wherein the first pressure threshold ranges from 0.130MPa to 0.140MPa, and the second pressure threshold ranges from 0.145MPa to 0.155 MPa.

Further, the mass flow rate of the internal rocket is reduced by reducing the fuel oxidant supply of the internal rocket.

Furthermore, the air inlet channel is a mixed pressure type air inlet channel.

Further, the built-in rocket is positioned at the outlet of the isolation section and is arranged on the side surface of the isolation section.

Further, the built-in rocket is a liquid fuel rocket.

Compared with the prior art, the invention provides a starting control method of an air inlet channel of a rocket-based combined cycle engine, which is applied to the rocket-based combined engine and comprises the following steps: intake duct, isolation section, combustion chamber and built-in rocket, wherein: the air inlet channel, the isolation section and the combustion chamber are sequentially connected, air flow flows in from the air inlet channel, is discharged from the tail end of the combustion chamber after passing through the isolation section and working in the combustion chamber, whether the indoor pressure intensity of the combustion chamber is larger than a first pressure intensity threshold value and smaller than or equal to a second pressure intensity threshold value is judged, if yes, the mass flow rate of the built-in rocket is reduced, and the injection quantity of secondary fuel is reduced, so that the indoor pressure intensity of the combustion chamber is reduced, when the indoor pressure intensity of the combustion chamber is reduced to be smaller than the first pressure intensity threshold value, the mass flow rate of the built-in rocket is increased, the injection quantity of the secondary fuel is increased, so that the indoor pressure intensity in the combustion chamber is increased, and the indoor pressure intensity in the combustion chamber is increased to the first pressure intensity threshold value, the application changes the jet flow radius of the built-in rocket by changing the working state of the built-in rocket, so as to adjust the actual equivalent internal contraction ratio of the air, therefore, the non-starting of the air inlet is restrained, the regulation and control capability of restraining the non-starting of the air inlet is effectively improved, and the working performance of the rocket-based combined engine is improved.

Drawings

FIG. 1 is a schematic diagram of a rocket-based compound engine in an embodiment of the present invention;

FIG. 2 is another schematic view of a rocket-based compound engine in accordance with an embodiment of the present invention;

fig. 3 is a mach number cloud chart when the shock wave string moves forward to the average mach number of the isolation section and starts to obviously decrease (i.e. the inlet duct does not start the emergency warning) after the pressure of the combustion chamber is suddenly increased in the normal working state.

FIG. 4 is a Mach number cloud for suppressing misfire by reducing internal rocket mass flow rate and reducing combustor pressure.

Figure 5 is a mach number cloud suppressing misfire by increasing the internal rocket mass flow rate and restoring the combustor pressure.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Referring to fig. 1 to 5, the present invention provides a method for controlling the start of an intake port of a rocket-based combined cycle engine, which is applied to a rocket-based combined engine, and the rocket-based combined engine includes: the device comprises an air inlet channel 1, an isolation section 2, a combustion chamber 3 and a built-in rocket 4.

The air inlet 1, the isolation section 2 and the combustion chamber 3 are sequentially connected, air flow flows in from the air inlet 1, passes through the isolation section 2, works in the combustion chamber 3 and then is discharged outwards from the tail end of the combustion chamber 3; the built-in rocket 4 is positioned at the outlet of the isolation section 2 and is arranged at the side surface of the isolation section 2, and the built-in rocket 4 is communicated with the combustion chamber 3 and provides combustion energy for the built-in rocket 4 by fuel contained in the combustion chamber 3. The air inlet 1 is a binary mixed pressure type air inlet 1. The built-in rocket 4 is a liquid fuel rocket.

In this embodiment, whether the mach number of the throat of the intake duct is greater than 1 is used as a basis for judging whether the intake duct is started, when the mach number of the throat of the intake duct is greater than 1, it is determined that the intake duct 1 is started, and when the mach number of the throat of the intake duct is less than 1, it is determined that the intake duct 1 is in an un-started state.

Referring to fig. 3, when the pressure in the combustion chamber 3 increases from 0.135MPa to 0.15MPa, it can be seen from the mach number cloud chart in fig. 3 that the position of the internal shock wave string shifts forward, and the mach number at the exit plane of the isolation section 2 starts to decrease significantly as an emergency warning that the intake duct 1 is not started. At this time, if no measure is taken, the shock wave string will continue to move forward until the air inlet 1 is moved out, and an arc shock wave is formed in front of the air inlet.

In order to reduce the influence of the non-starting of the air inlet on the overall performance of the aircraft, measures need to be taken when the air inlet is not started for emergency early warning, so that the non-starting of the air inlet is effectively inhibited.

In the present embodiment, it is determined whether the indoor pressure of the combustion chamber 3 is greater than the first pressure threshold and less than or equal to the second pressure threshold, and if so, the mass flow rate of the internal rocket 4 is reduced to 0.20kg/s, and the injection amount of the secondary fuel is appropriately reduced, so that the indoor pressure of the combustion chamber 3 is reduced. When the emergency early warning is generated when the air inlet does not start, the mass flow rate of the built-in rocket 4 is reduced by reducing the fuel and oxidant supply of the built-in rocket 4, and when the mass flow rate of the built-in rocket 4 is reduced to 0.2kg/s and the pressure of the combustion chamber 3 is reduced to 0.1MPa, the Mach number of the throat of the air inlet 1 is recovered to be larger than 1, as shown in FIG. 4. When the average mach number at the exit of the isolation section 2 also tends to be stable.

When the indoor pressure of the combustion chamber 3 is reduced to be less than a first pressure threshold value, the mass flow rate of the built-in rocket 4 is increased to 0.30kg/s-0.35kg/s, and the injection amount of the secondary fuel is properly increased, so that the indoor pressure in the combustion chamber 3 is increased and the indoor pressure in the combustion chamber 3 is increased to the first pressure threshold value, wherein the first pressure threshold value ranges from 0.130MPa to 0.140MPa, and the second pressure threshold value ranges from 0.145MPa to 0.155 MPa. The normal operation state is restored again (the mass flow rate of the built-in rocket is 0.3kg/s, and the back pressure of the combustion chamber is 0.135MPa), as shown in FIG. 5, the non-starting of the air inlet is inhibited.

In this example, the non-starting of the air inlet channel can be restrained in a mode of directly improving the mass flow of the built-in rocket by utilizing the sweeping effect of the high-speed jet flow of the built-in rocket on the low-energy boundary layer to keep the pressure of the combustion chamber unchanged or properly reduce the pressure. In the embodiment, when the emergency early warning is generated when the air inlet is not started, the flow of the built-in rocket is increased to 0.33kg/s from 0.3kg/s in the normal working state, and the pressure of the combustion chamber is recovered to 0.135MPa in the normal working state.

It should be noted that, in this example, the non-start of the air intake duct may also be suppressed in a manner of directly increasing the mass flow of the internal rocket by using the purging effect of the high-speed jet of the internal rocket on the low-energy boundary layer to keep the pressure of the combustion chamber unchanged or properly reduce the pressure.

In summary, the present invention provides a method for controlling the start of an air intake duct of a rocket-based combined cycle engine, which is applied to a rocket-based combined engine, and the rocket-based combined engine includes: intake duct, isolation section, combustion chamber and built-in rocket, wherein: the air inlet channel, the isolation section and the combustion chamber are sequentially connected, air flow flows in from the air inlet channel, is discharged from the tail end of the combustion chamber after passing through the isolation section and working in the combustion chamber, whether the indoor pressure intensity of the combustion chamber is larger than a first pressure intensity threshold value and smaller than or equal to a second pressure intensity threshold value is judged, if yes, the mass flow rate of the built-in rocket is reduced, and the injection quantity of secondary fuel is reduced, so that the indoor pressure intensity of the combustion chamber is reduced, when the indoor pressure intensity of the combustion chamber is reduced to be smaller than the first pressure intensity threshold value, the mass flow rate of the built-in rocket is increased, the injection quantity of the secondary fuel is increased, so that the indoor pressure intensity in the combustion chamber is increased, and the indoor pressure intensity in the combustion chamber is increased to the first pressure intensity threshold value, the application changes the jet flow radius of the built-in rocket by changing the working state of the built-in rocket, so as to adjust the actual equivalent internal contraction ratio of the air, therefore, the non-starting of the air inlet is restrained, the regulation and control capability of restraining the non-starting of the air inlet is effectively improved, and the working performance of the rocket-based combined engine is improved.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.