JPH10238408A - Expander cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To responsively control a thrust. SOLUTION: An expander cycle engine comprises a fuel turbo pump 1 for pumping liquid fuel, which is used as a coolant for a combustion chamber 3. After the fuel turbo pump 1 is driven with a vaporized fuel, the vaporized fuel is supplied into the combustion chamber 3. In the expander cycle engine, a thrust control valve 6 is provided which adjusts driving force of the fuel turbo pump 1, thereby controlling a fuel supply amount by bypassing the vaporized fuel into the combustion chamber 3. Further, a compression sensor 8 for detecting thrust is provided inside the combustion chamber 3, a control system activating the thrust control valve 6 such that the detected thrust follows up a command value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expander cycle engine that uses liquid fuel for cooling and supplies liquid fuel using the pressure of vaporized fuel.
The present invention relates to an expander cycle engine capable of controlling thrust with good response.

[0002]

2. Description of the Related Art An expander cycle engine is a rocket engine using liquid hydrogen as a fuel and liquid oxygen as an oxidant, and converts the liquid hydrogen into hydrogen gas by using the liquid hydrogen for cooling a combustion chamber. The hydrogen gas is finally supplied as fuel into the combustion chamber. In addition, a turbo pump is used for the fuel pump for pumping liquid hydrogen from the storage unit and the oxidant pump for pumping liquid oxygen, and the hydrogen gas is passed through these turbo pumps before being supplied to the combustion chamber. The turbo pump is driven by pressure.

It is desired that recent rockets can be returned from space and reused as many times as possible. For this purpose, it is necessary to configure the rocket so that it can land softly on a celestial body. To do so, a rocket engine that can control thrust is indispensable.

[0004]

The conventional rocket engine is used exclusively at full throttle, and it is difficult to control the thrust by controlling the fuel supply amount based on a command value. Although possible,
There is a problem with its responsiveness. In particular, the expander cycle engine does not respond quickly to the thrust command,
Controlling the altitude and attitude of the rocket aircraft at the time of landing by thrust control was insufficient in terms of thrust accuracy and response speed.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide an expander cycle engine capable of controlling thrust with good response.

[0006]

According to the present invention, there is provided a fuel turbo pump for pumping a liquid fuel, wherein the liquid fuel is used for cooling a combustion chamber, and a vaporized fuel is used. In the expander cycle engine that supplies the fuel into the combustion chamber after driving the fuel turbo pump, the driving force of the fuel turbo pump is increased or decreased by bypassing the vaporized fuel into the combustion chamber. A thrust control valve for adjusting the fuel supply amount is provided, and a pressure sensor for detecting a thrust in the combustion chamber is provided,
A control system is provided for operating the thrust control valve so that the detected thrust follows the command value.

The oxidizing turbo pump for pumping the liquid oxidant with the vaporized fuel is driven, and the driving power of the oxidizing turbo pump is increased or decreased by bypassing the vaporized fuel into the combustion chamber. A mixing ratio control valve may be provided to adjust the mixing ratio.

[0008] The control system may be provided with a filter for removing noise due to combustion vibration from the thrust detected by the pressure sensor.

[0009]

An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

As shown in FIG. 1, the expander cycle engine is provided with a fuel turbo pump 1 for pumping liquid hydrogen LH2. An intake 1a on the load side of the fuel turbo pump 1 is connected to a storage unit (not shown) for liquid hydrogen through a pipe, and a discharge port 1b on the load side of the fuel turbo pump 1 is Pipe 2a is connected. The liquid hydrogen pipe 2a is guided to the combustion chamber 3 and is connected to an upstream end of a cooling system 3a surrounding the combustion chamber 3. A first pipe 2b for hydrogen gas for discharging hydrogen gas vaporized in the cooling system 3a is connected to a downstream end of the cooling system 3a. The first pipe 2b for hydrogen gas is connected to a driving side of the turbo pump 1 for fuel. It is connected to the intake 1c. A second pipe 2c for hydrogen gas is connected from a discharge port 1d on the drive side of the turbo pump 1 for fuel to an intake 4c on the drive side of the turbo pump 4 for oxidant. A third hydrogen gas pipe 2d connected to the outlet 4d is guided to the combustion chamber 3 and is opened into the combustion chamber 3.

On the other hand, an intake 4a on the load side of the oxidizer turbo pump 4 for pumping the liquid oxygen LOX is connected to a storage unit (not shown) for the liquid oxygen via a pipe. A liquid oxygen pipe 5 is connected to a discharge port 4b on the load side of 4. The liquid oxygen pipe 5 is led to the combustion chamber 3 and is opened into the combustion chamber 3.

According to the present invention, a thrust control system bypass pipe 2e is provided between the first hydrogen gas pipe 2b and the third hydrogen gas pipe 2d. A thrust control valve 6 is inserted into the thrust control system bypass pipe 2e. Further, a mixing ratio control system bypass pipe 2f is provided between the hydrogen gas second pipe 2c and the hydrogen gas third pipe 2d. A mixture ratio control valve 7 is inserted into the mixture ratio control system bypass pipe 2f. A pressure sensor 8 for detecting the pressure in the combustion chamber, that is, the thrust, is provided in the combustion chamber 3. A control system (not shown) for operating the thrust control valve is provided so that the thrust detected by the pressure sensor 8 follows the thrust command value.

As shown in FIG. 2, the control system according to the present embodiment includes a mechanism 20 for actually driving the thrust control valve.
And a circuit section 30 for controlling the driving. The mechanism unit 20 includes a servomotor 21 and a servomotor 21.
And an actuator 22 having a valve shaft that translates the rotational motion of the thrust control valve 6 with a ball screw and moves linearly. The opening of the thrust control valve 6 is adjusted in accordance with the linear motion of the valve shaft. Therefore, by controlling the position of the actuator 22, the thrust of the rocket engine can be changed. To detect the position of the actuator 22,
A potentiometer (not shown) for detecting the straight traveling position and a resolver 23 for detecting the rotational position of the servomotor 21 are provided. For example, during the valve operation, the signal of the resolver 23 is used to return the actuator 22 to the home position. Use the potentiometer signal during operation.

The circuit section 30 includes a servo driver 31 for controlling the speed of the servo motor, and a speed for issuing a speed command to the servo driver 31 by feeding back a position signal from the servo driver 31 to the position command based on the position command. A command circuit 32, a position command circuit 33 for issuing a position command to the speed command circuit 32 to change the thrust, and a pressure in the combustion chamber 3 detected by the pressure sensor 8, that is, a position command circuit 33 for detecting the rocket engine thrust. Thrust command value input section 34
Thrust feedback circuit 34 that feeds back to 1
Are provided. The speed command circuit 32 and the position command circuit 33 are constituted by a computer. The thrust feedback circuit 34 includes an amplifier 35 that amplifies the detection signal of the pressure sensor 8, a filter 36 that cuts off high frequency,
A D converter 37 is provided. The filter removes noise due to combustion vibration from the thrust detected by the pressure sensor, and a digital filter may be provided at a stage subsequent to the A / D converter 37.

As described above, in the control system according to the present embodiment, a local speed control feedback loop is formed by the servo driver 31, the servo motor 21, and the resolver 23.
A local position control feedback loop is configured by the speed command circuit 32 and the servo driver 31, and controls the position of the actuator for thrust control. Then, the rocket engine thrust, which is the final output, is fed back to the input portion of the thrust command value, thereby forming the entire thrust control feedback loop. The reason why the multiple feedback loops are configured in this way is that a servo driver 31 and a servo motor 21 that are set are used. The control system is not limited to this embodiment, and may be configured to operate the thrust control valve so that the detected thrust follows the command value.

Next, the thrust control operation of the expander cycle engine of the present invention will be described. Liquid hydrogen LH2 is pumped out by fuel turbopump 1 and sent to cooling system 3a. By cooling the combustion chamber 3, the liquid hydrogen becomes hydrogen gas, and the fuel turbo pump 1 is driven by the pressure. This hydrogen gas is supplied into the combustion chamber 3 after driving the fuel turbo pump 1. At this time, if the thrust control valve 6 is completely closed, hydrogen gas corresponding to the total amount of the pumped liquid hydrogen acts to drive the fuel turbo pump 1 and is supplied into the combustion chamber 3. When the thrust control valve 6 is opened, a part of the hydrogen gas is bypassed into the combustion chamber 3 without being distributed to the fuel turbo pump 1 according to the opening degree. For this reason, the driving force of the fuel turbo pump 1 decreases, and the pumping amount of liquid hydrogen decreases. As the pumping amount of liquid hydrogen decreases, the amount of hydrogen gas supplied into the combustion chamber 3 decreases, and the thrust by combustion decreases. Also,
Due to the decrease in combustion, the pressure of the hydrogen gas vaporized in the cooling system 3a decreases, and the driving force of the fuel turbo pump 1 further decreases. If the thrust control is an open-loop control that merely issues a command value of the fuel supply amount, thrust control cannot be performed well. However, in the present invention, since the thrust control valve 6 is operated so that the thrust detected in the combustion chamber follows the command value, thrust control can be performed with high accuracy and quick response.

As described above, by controlling the opening of the thrust control valve 6, the driving force of the fuel turbo pump 1 can be increased or decreased, and the fuel supply amount can be adjusted. Similarly,
By controlling the opening of the mixing ratio control valve 7, the driving force of the oxidizing agent turbo pump 4 can be increased or decreased to adjust the mixing ratio. As described above, thrust control with higher accuracy can be realized by adjusting the mixture ratio. Further, the thrust detected by the pressure sensor 8 includes noise due to combustion vibration. If this is fed back as it is, the control becomes unstable. However, since the noise is removed by the filter 36, the control is performed. Becomes stable.

In the above embodiment, liquid oxygen is supplied directly into the combustion chamber 3, but liquid oxygen may be vaporized and used for driving a turbo pump. In this case, the driving force of the turbo pump is increased or decreased by bypassing the oxygen supplied to the turbo pump into the combustion chamber.

Such thrust control works advantageously when the rocket aircraft lands. That is, when the rocket launches,
It is only necessary to obtain a large thrust at full throttle in order to ascend as quickly as possible. On the other hand, during landing, the thrust must be reduced enough to gradually decelerate the rocket aircraft.
Moreover, fine adjustment is required. In this regard, the expander cycle engine of the present invention can perform thrust control with high accuracy and quick response, and is therefore suitable for a rocket that is returned from space and reused many times.

[0020]

The present invention exhibits the following excellent effects.

(1) Since a rocket engine with sufficient thrust control accuracy and response speed can be obtained, altitude control and attitude control during landing of the rocket aircraft are facilitated.

[Brief description of the drawings]

FIG. 1 is a fuel system diagram of an expander cycle engine showing one embodiment of the present invention.

FIG. 2 is a block diagram of a control system of an expander cycle engine according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbo pump for fuel 3 Combustion chamber 3a Cooling system 4 Turbo pump for oxidant 6 Thrust control valve 7 Mixing ratio control valve 8 Pressure sensor 36 Filter

Claims (3)

[Claims] 1. A fuel turbo pump for pumping liquid fuel, the liquid fuel being used for cooling a combustion chamber, and the fuel turbo pump being driven by vaporized fuel.
In an expander cycle engine that supplies the fuel into the combustion chamber, a thrust control valve that adjusts the fuel supply amount by increasing or decreasing the driving force of the fuel turbo pump by bypassing the vaporized fuel into the combustion chamber is provided. An expander cycle engine further comprising a pressure sensor for detecting thrust in the combustion chamber, and a control system for operating the thrust control valve so that the detected thrust follows a command value. 2. The method according to claim 1, further comprising: driving a turbo pump for oxidizing agent that pumps a liquid oxidant with the vaporized fuel, and bypassing the vaporized fuel into a combustion chamber to reduce a driving force of the turbo pump for oxidizing agent. 2. The expander cycle engine according to claim 1, further comprising a mixture ratio control valve that adjusts the mixture ratio by increasing or decreasing the mixture ratio. 3. The expander cycle engine according to claim 1, wherein the control system is provided with a filter for removing noise due to combustion vibration from the thrust detected by the pressure sensor.