RU2744223C1 - Mixing head of chirp chamber, operating according to scheme with afterburning of generator gas - Google Patents

Abstract

FIELD: rocket equipment.

SUBSTANCE: invention relates to rocket engineering and can be used in creation of controlled rocket engines. Liquid-propellant chamber of the liquid-propellant engine operating according to the scheme with afterburning of the generator gas contains gas and liquid component supply branch pipes, housing and fire bottom with two-component nozzles fixed between them, according to invention nozzle of generator gas nozzle is made in form of Laval nozzle with annular ribbed inlet part, inside which there is spring-loaded shaped rod with end, which external surface interacts with inner surface of annular rib with inlet part, in rod end there are holes, on inlet side of nozzle into annular ribs inlet part is tightly installed back wall, and in the central part of the pin there is a hole, on the external surface of the butt end of the pin there are labyrinth grooves, the external surface of the butt end of the pin is coated with silver.

EFFECT: invention provides higher thrust impulse, as well as higher reliability of engine operation.

3 cl, 3 dwg

Description

The invention relates to the field of rocketry and can be used to create adjustable rocket engines.

At present, most rocket engines operate according to the scheme with generator gas afterburning, in order to ensure high efficiency, when one of the propellant components enters the chamber head in gaseous form, and the other in liquid form.

One of the main problems in the creation of a variable thrust rocket engine is to obtain a high specific impulse value at various engine operating modes. Traction control in such engines is carried out by changing the consumption of fuel components through the nozzles of the mixing head. A decrease in the consumption of the liquid component of the fuel leads to a quadratic change in the pressure drop across the nozzles, and the gaseous one to a linear one. When the mode is less than the nominal, a change in the pressure drop across the injectors leads to a deterioration in the conditions of mixture formation, a decrease in the completeness of fuel combustion and, accordingly, the loss of specific thrust impulse. In addition, at low engine operating conditions, due to the low pressure drop across the injectors, unstable combustion occurs in the combustion chamber, which leads to its destruction.

Many designs of pin nozzles are known (for example, US patent No. US 7.703.274 B2 dated 04/27/2010), the tip of a pin nozzle with active cooling (US patent No. US 7.503.511 B2 dated 04/27/2009), coaxial mixing head LRE (US patent No. 15.3.699.722 dated 10.24.1972), which allow you to implement throttling with high efficiency.

In addition, in order to ensure deep thrust control, in addition to special control measures for the liquid line, it is necessary to perform special measures for the gaseous line.

But the main drawback of all these designs is their great complexity, and most importantly, the impossibility of their implementation in the mixing heads of large thrust rocket engine engines, in the heads of which there are from 200 to 500 mixing elements.

The known design of a device for changing the thrust of a liquid-propellant engine, set forth in the US patent [19], [11], Spencer [45] (taken as a prototype), in which deep regulation is carried out along the liquid and gaseous lines due to the kinematic interaction of two movable bushings and a pin.

This design of the device for changing the thrust has significant disadvantages:

- the kinematic interaction of the movable bushings and the pin with each other is carried out due to a special drive and gear, which significantly complicates the design and increases the dimensions;

- this device for changing the thrust can be used in a single copy in the combustion chamber, which for a high-thrust engine leads to a significant decrease in efficiency.

The task is achieved by the fact that the mixing head of the LPRE chamber, operating according to the scheme with the afterburning of the generator gas, containing the nozzles for supplying the generator gas and the liquid component, the body and the fire bottom with two-component nozzles fixed between them, according to the statement:

- the cavity of the generator gas of the nozzle is made in the form of a Laval nozzle with an annular inlet part with ribs, inside of which a spring-loaded profiled pin with an end is installed, the outer surface of which interacts with the inner surface of the inlet part, annular with ribs, holes are made in the end of the pin, from the inlet side of the nozzle into an annular with ribs inlet part is hermetically installed back wall, and a hole is made in the central part of the pin;

- labyrinth grooves are made on the outer surface of the end of the pin;

- the outer surface of the end of the pin is coated with silver.

The essence of the invention is illustrated by the diagrams shown in FIG. 1, 2, 3.

FIG. 1 shows the position of the elements of the mixing head in the initial position, where the two-component nozzle 1 is soldered to the head body 2 and the fire bottom 3. The profiled pin 4 is pressed by the spring 5 against the stop 6 of the nozzle 1.

7 - the minimum section of the Laval nozzle;

8 - generator gas cavity;

9 - inlet part of the Laval nozzle;

10 - holes in the end face 14 of the profiled pin 4;

11 - cavity of pin 4;

12 - hole in the profiled pin 4;

13 - the outlet part of the nozzle 1;

14 - the end face of the profiled pin 4;

16 - back wall.

FIG. 2 shows:

9 - inlet part of the Laval nozzle;

15 - ribs in the entrance part;

16 - back wall.

FIG. 3 shows the position of the elements of the mixing head at the nominal operating mode, where:

4 - profiled pin;

5 - spring;

7 - the minimum section of the Laval nozzle;

8 - generator gas cavity;

9 - inlet part of the Laval nozzle.

The mixing head works as follows. In the initial position, the profiled pin 4 is pressed by the spring 5 against the stop 6 of the nozzle 1, while it overlaps the minimum section 7 of the Laval nozzle as much as possible.

When the engine reaches the nominal (main) mode, in the cavity of the generator gas 8 and in the inlet of the Laval nozzle 9, the pressure in the nozzle rises. As a result of the pressure increase, a force appears on the profiled pin, which causes the pin to move gradually, compressing the spring 5 and increasing the minimum cross-sectional area 7 of the Laval nozzle. When the pin moves, the generator gas from the inlet 9 of the Laval nozzle through the holes 10, the cavity 11 of the profiled pin 4 and the hole 12 enters the outlet 13 of the nozzle 1, ensuring its smooth movement.

At the nominal steady-state mode, the pin 4 is in the extreme position under the action of the steady-state pressure, while the area of the minimum section 7 of the Laval nozzle is maximally open.

This position of the profiled pin 4 is maintained during the entire engine operation time at the nominal mode.

When the engine switches to throttling mode (due to a decrease in fuel consumption), the pressure in the cavity of the generator gas 8 and at the inlet 9 of the nozzle 1 in the Laval nozzle decreases, and, under the action of the force of the spring 5 on the end face 6 of the profiled pin 4, it moves, overlapping its profiled part of the minimum cross-sectional area 7 of the Laval nozzle.

When the engine is turned off, the pressure in the cavity of the generator gas 8 drops, and the pin, under the action of the spring force, returns to its original position to the stop up to the ledge 6 of the nozzle 1, overlapping with its maximum profiled part the area of the minimum section 7 of the Laval nozzle.

The proposed design of the mixing head makes it possible to obtain deep throttling in the generator gas, while maintaining an increased differential across the nozzle and ensuring the completeness of combustion of the fuel components.

The use of the proposed technical solution makes it possible to increase the specific thrust impulse in throttling modes and to ensure the stable operation of the mixing head, thereby increasing the reliability of the engine operation.

Claims (3)

1. Mixing head of a liquid-propellant engine chamber operating according to a scheme with generator gas afterburning, containing nozzles for supplying a generator gas and a liquid component, a body and a fire bottom with two-component nozzles fixed between them, characterized in that the cavity of the generator gas of the nozzle is made in the form of a Laval nozzle with an annular with ribs inlet part, inside of which a spring-loaded profiled pin with an end is installed, the outer surface of which interacts with the inner surface of the inlet ring with ribs, holes are made in the end of the pin, from the inlet side of the nozzle into the inlet ring with ribs, a hermetically sealed back wall is installed in a hole is made in the central part of the pin. 2. The mixing head of the liquid-propellant engine chamber operating according to the scheme with the afterburning of the generator gas, containing the nozzles for supplying the generator gas and the liquid component, the body and the fire bottom with two-component nozzles fixed between them according to claim 1, characterized in that labyrinths are made on the outer surface of the end of the pin grooves. 3. The mixing head of the liquid-propellant engine chamber operating according to the scheme with generator gas afterburning, containing the nozzles for supplying the generator gas and liquid component, the body and the fire bottom with two-component nozzles fixed between them according to claim 1, characterized in that the outer surface of the end of the pin is coated with silver.

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