RU2238424C1 - Method of operation of liquid-propellant rocket engine with vapor-liquid loop in propellant turbopump delivery system - Google Patents

Abstract

FIELD: liquid-propellant rocket engines.

SUBSTANCE: proposed method includes use of heat of combusted products to transform liquid working medium into vapor with supercritical temperature and pressure. After execution of work, vapor is again transformed into liquid using for cooling waste vapor of heat exchanger-condenser, cold-retaining capacity of propellant with delivery of condensate into corresponding pump part of liquid working medium getting out of pump is introduced into waste vapor, thus providing partial condensing with formation of wet vapor at inlet of working duct of heat exchanger-condenser.

EFFECT: improved overall and mass characteristics of heat exchanger-condenser.

5 cl, 2 dwg

Description

The invention relates to liquid-propellant rocket engines (LRE), and specifically to a turbo-pumped liquid propellant rocket engine consisting of separately stored oxidizer and fuel, at least one of these fuel components (usually an oxygen oxidizer) is cryogenic.

A known method of operation of a liquid-propellant liquid propellant liquid propellant circuit in a turbopump fuel supply system, including using the heat of the combustion products to convert the working fluid from the original liquid substance to steam with supercritical temperature and pressure, which after work is returned to the liquid using the coolant of rocket fuel during cooling spent steam in a heat exchanger-condenser, and the condensate is returned to the appropriate pump (see US Pat. RU 2155273 C1, 08/18/1999 - prototype of the invention).

The first prerequisite for the operation of a liquid-propellant rocket engine with a steam-liquid circuit in a turbopump fuel supply system is to ensure the energy balance of this system, that is, the equality between the available turbine power and the total pump power. To obtain high values of specific impulse thrust of the rocket engine (I _y ) it is necessary to create a high pressure in the chamber (p _to ). In this case, to ensure the energy balance, it is necessary to heat a sufficient mass of the turbine’s working fluid (for example, ammonia) to a high temperature and generate the generated steam (more precisely, gas) at a high pressure drop. At the end of the operating cycle of the supply system, it is necessary to give the residual heat of the spent steam to the cold fuel entering the LRE in order to cool the steam until it is completely converted to condensate.

Typically, the main coolant of fuel is concentrated in a cryogenic oxygen oxidizer, which has a temperature of ≈100 K at the outlet of the pump. Ultimately, the heat exchanger-condenser is a critical factor for the technical implementation of the LRE operation method under consideration.

In the general case, this unit contains three working sections: a section for cooling exhaust (e.g., ammonia) steam to saturation temperature, a section for wet steam (condensation proper), and a condensate cooling section for ensuring pump-free operation. At a high p value, _the implementation of the working process in a heat exchanger-condenser requires a very developed surface of this unit, and its mass is excessively large, which impedes the implementation of the prototype method.

The invention solves the technical problem of improving the overall dimensions of a heat exchanger-condenser.

The stated technical problem is solved by the fact that in the method of operation of the liquid-propellant liquid propellant liquid propellant circuit in a turbopump fuel supply system, the use of the heat of the combustion products of the fuel to turn the working fluid from the original liquid substance into steam with supercritical temperature and pressure, which is again turned into liquid after work using the cold resource of rocket fuel when cooling the exhaust steam in a heat exchanger-condenser, the condensate being returned to the corresponding pump, according to According to the invention, a part of the liquid working fluid is introduced into the exhaust steam at the outlet of the pump, partially condensing it with the formation of wet steam at the inlet to the working path of the heat exchanger-condenser.

In particular cases of the invention:

- the liquid introduced into the exhaust steam is pre-cooled by heat exchange with the fuel of rocket fuel, for which some of the mass of fuel consumed through the engine can be used;

- the liquid introduced into the exhaust steam is pre-cooled by heat exchange with the oxidizer of rocket fuel, for which some of the oxidizer mass consumed through the engine can be used.

When carrying out the invention, a technical result is expected that coincides with the essence of the problem being solved.

The invention is illustrated using figures 1 and 2, which presents the functional diagrams for the liquid propellant rocket engine operating according to the proposed method.

According to figure 1, the rocket engine contains a traction-generating chamber 1 with a nozzle head 1a, a combustion chamber 1b, and a supersonic jet nozzle 1c; the chamber body is formed by two coaxial shells (external and internal) forming the path 1d for the cooler duct. For fuel supply, the engine is provided with a turbopump unit (TNA), which contains a cryogenic oxidizer pump (usually liquefied oxygen) 2, a fuel pump (e.g. kerosene) 3, a pump 4 for supplying a condensed working fluid of a turbine (e.g. ammonia) and a steam turbine 5 By means of a high-pressure line 6 with a heat exchanger 7 placed in it, the pump 3 is connected to the nozzle head 1a. It is in communication with the pump 2 by means of a high-pressure line 8 with a heat exchanger-condenser 9 located in it. It is designed for cooling and condensing the exhaust steam of a turbine that enters through line 10; the condensate obtained is returned via line 11 to pump 4.

In the line 10 between the turbine and the heat exchanger-condenser there is a mixing device 12 designed to enter into the exhaust steam coming through the pipe 13 after pre-cooling in the heat exchanger 7 the mass of condensate taken from the line 14, which communicates the output of the pump 4 with the input of the cooling path 1d of the chamber. Its output is communicated by a pipeline 15 with the inlet of the turbine 5. The pump 4 together with the turbine 5, the heat exchanger-condenser 9, the mixing device 12, the cooling path 1d and the connecting supply lines form a closed loop for the circulation of the working fluid undergoing phase transformations. A circulation loop is connected to the indicated circuit (4-7-13-12-9-11-4).

The described LRE works as follows.

The propellant oxidizer entering the engine (for example, liquid oxygen) is pumped via line 8 to the nozzle head 1a of the chamber. Along the way, the oxidizing agent is heated in a heat exchanger-condenser 9 (from a hotter product from line 10). Fuel of rocket fuel (for example, kerosene) entering the liquid propellant rocket engine is fed by pump 3 along line 6 to the nozzle head 1a of the chamber. On the way, the fuel is heated in the heat exchanger 7 (from a hotter product from the line 14). In the combustion chamber 1b, the fuel components are burned, and the resulting high-temperature gas enters the jet nozzle 1c, creating a thrust chamber 1 (and the LRE as a whole). A working fluid circulating in a closed circuit (for example, ammonia) for driving a turbine 5 is supplied by a condensate pump 4 along line 14 to the cooling path 1d of the chamber. After it passes, the working fluid, converted into superheated steam (gas) with supercritical temperature and pressure, is fed through a pipe 15 to a turbine 5 leading the pumps 2, 3, 4 through a common shaft with them (usually consists of two parts connected by a spring). The exhaust steam of the turbine is fed through the line 10 sequentially to the mixer 12 and the heat exchanger-condenser 9. In the first of these units, condensate is also supplied via line 13 from the line 14, cooling it along the way in the heat exchanger 7 with cooler fuel. The cooled condensate is mixed in the mixer 12 with the turbine exhaust gas stream, resulting in moist steam, which then enters the working path of the heat exchanger-condenser 9. The condensed product is fed through a pipe 11 to the pump 4, and the duty cycle of the supply system is repeated.

1, the strokes show a heat exchanger 7a for cooling the condensate supplied to the mixer 12, due to the use of the oxidizer coolant (and not fuel, as in the case of heat exchanger 7).

Figure 2 presents the option of placing in the line between the turbine 5 and pump 4 not one, but two heat exchangers: heat exchanger-cooler 9a and heat exchanger-condenser 9b. In the first unit, the turbine exhaust gas is pre-cooled (with an oxidizing agent), which is then diluted in the mixer 12a with chilled condensate coming from the unit 7 through a pipe 13a. In unit 9b, the resulting vapor-liquid mixture is condensed.

The invention is not limited to those shown in figures 1 and 2, for example:

- the presence of heat exchangers 7 and 7a is not required;

- steam leaving the cooling path 1d before being fed to the turbine 5 can be additionally heated with gas generated when part of the fuel is burned in a special gas generator;

- the number of impellers in the pumps and turbine may be different;

- the use of the same product as the working fluid of the turbine of the propellant fuel (for example, liquefied methane or natural gas), allows you to combine the functions (and design) of pumps 3 and 4 to one degree or another, etc.

The technical result from the implementation of the invention will show a specific example: for a liquid propellant liquid propellant rocket engine with a thrust of 1, 2 MN, operating according to the diagram according to Fig. 1 without heat exchangers 7 and 7a.

The initial data for calculating the energy balance of the rocket engine:

- pressure in the chamber 15 MPa;

- oxidizer consumption through the engine 260 kg / s;

- fuel consumption through the engine 100 kg / s;

- the working fluid of the turbine is ammonia vapor (gas) with supercritical temperature and pressure.

Calculation Results:

- steam flow through the turbine 36 kg / s;

- steam temperature at the inlet / outlet of the turbine 300/60 ° C;

- steam pressure at the inlet / outlet of the turbine 17 / 0.8 MPa;

- condensate flow through the pump 41 kg / s;

- ammonia temperature at the inlet / outlet of the condensate pump 0/12 ° C;

- ammonia pressure at the inlet / outlet of the condensate pump 0.6 / 23 MPa;

- at the outlet of the mixer 12 pairs has a pressure of 0.9 MPa and a temperature of 21 ° C with a degree of dryness of 0.96;

- working surface of the heat exchanger-condenser 60 m ² ;

- the mass of the duralumin design of the heat exchanger-condenser is 170 kg.

Thus, in the particular example shown, the invention enables the expander to a high value p _k (which correspond to high performance I _y) as acceptable size and weight of the heat exchanger-condenser. This technical result was obtained due to the fact that the input to the working path of the heat exchanger-condenser is supplied not from overheated exhaust steam directly from the turbine outlet, but from wet steam (with a dry degree of 0.96), i.e., a vapor-liquid mixture in which condensation centers are present that contribute to the implementation of the condensation process.

Claims (5)

1. The method of operation of a liquid-propellant rocket engine with a vapor-liquid circuit in a turbopump fuel supply system, comprising using the heat of the fuel combustion products to convert the working fluid from the initial liquid substance to steam with supercritical temperature and pressure, which after work is again converted into liquid using the rocket coolant fuel when cooling the exhaust steam in a heat exchanger-condenser, and the condensate is returned to the appropriate pump, characterized in that part of the liquid at the outlet of the pump, the working fluid is introduced into the exhaust steam, partially condensing with the formation of wet steam at the entrance to the working path of the heat exchanger-condenser. 2. The method of operation of a liquid rocket engine according to claim 1, characterized in that the liquid introduced into the exhaust steam is pre-cooled by heat exchange with combustible rocket fuel. 3. The method of operation of a liquid rocket engine according to claim 1, characterized in that the liquid introduced into the exhaust steam is pre-cooled by heat exchange with an oxidizer of rocket fuel. 4. The method of operation of a liquid-propellant rocket engine according to claim 2, characterized in that a part of the fuel mass consumed through the engine is used to cool the liquid. 5. The method of operation of a liquid rocket engine according to claim 3, characterized in that for the cooling of the liquid use part of the oxidizer mass consumed through the engine.

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