RU2690304C1 - Method of flight-design tests of on-board system for evaporation of liquid fuel residues in tank of spent carrier rocket stage - Google Patents

Abstract

FIELD: machine building.SUBSTANCE: invention relates to autonomous onboard descent system (AODS) of spent stage of carrier rocket with cruise liquid-propellant rocket engines. Proposed method comprises tests of AODS evaporation system of residues of liquid fuel in spent stage tank during launching of carrier rocket excluding other AODS elements. Prior to start-up weight and temperature of remainder of fuel and gas of pressurisation is determined in tank after disconnection of cruise liquid-propellant engine. Amount of heat required for evaporation of fuel residue in the tank is calculated, and after separation of the spent stage from the carrier rocket, this heat is affected by this fuel residue. Resulting vapor-gas mixture is discharged through membrane-free nozzles. In the section of maximum speed head, strength of the tank is provided by creation of pressure in it. Processes in the tank are completed to heights of 1–5 km, and temperature and pressure of the vapor-gas mixture is limited based on the strength of the tank.EFFECT: technical result is flight development of evaporation system of fuel residues in spent stage tank in conditions close to standard operating conditions with minimum resource consumption.1 cl

Description

The invention relates to flight test design (LCI) of promising elements of rocket and space technology, in particular, to onboard evaporation systems of non-producing residues of liquid fuel components of launch vehicles (PH) with cruise liquid rocket engines (LRE) in tanks of spent stages (OS) after completion of the mission (turning off the sustainer rocket engine and OS separation).

After turning off the cruise rocket engine, as a rule, non-produced fuel residues remain in the tanks of the LV stages and main pipelines. Their values can reach up to 3% and higher from the initial fuel filling. These fuel residues are the causes of the OS explosions in the orbits of launching the launch vehicle, as well as explosions of the lower operating systems when driving on atmospheric parts of the descent trajectories, when hitting the ground in areas of fall, which can lead to fires of vegetation in areas of fall.

There are various options for reducing non-producing liquid fuel residues in tanks, for example, (Prince 1 Trushlyakov VI, Kudentsov V.Yu., Lempert DB. Development of additional spaceborne systems for space launch vehicles // Flight. - 2010. - № 3. P. 3-10), which proposes the development of an autonomous airborne descent system (ABSS) of the spent LV stage. Considering the fact that such a system is new, previously not used as part of the onboard RN systems, a significant amount of its ground and LCIs are needed, however, as a rule, such tests are divided into successive stages on a principle from simple to complex.

The closest technical solution for organizing an LCI of such a system is RF patent No. 2414391 B64G 1/26, WS64C 15/14 “The method of descent of the separating part of the stage of a space rocket and the device for its implementation”, destination on the liquid components of the fuel in a given area of incidence, based on the stabilization of the RCh position of the propulsion system forwards, orientation and controlled movement of RCh. After separation of the RCh, a maneuver of descent to a given drop area is carried out at the expense of the energy contained in the unexplored residues of the components of liquid fuel based on their gasification and supply of the descent to the gas rocket propulsion system. The motion of the center of mass and around the center of mass of the PM is controlled by the deviations of the chambers of the gas jet propulsion system. PTS at the time of switching off the gas jet propulsion system provide an angular position in space corresponding to the minimum angle of attack when it enters the dense layers of the atmosphere, and rotate the ROC around its longitudinal axis. The value of the unworked residues of liquid fuel is formed taking into account the descent of PTS to a given drop area. The completion of the active part of the descent maneuver is carried out before entering the dense layers of the atmosphere and preserving the control of the PM by means of the chambers of the gas-jet propulsion system. POC missiles include a control and navigation system, a gasification system. On the upper bottom of the fuel compartment are four cameras, each of which is equipped with a drive. The gasification system has an autonomous gas generator with a membrane system for supplying components of the fuel, exciters of acoustic oscillations, placed on the nozzles of the input of the coolant into the fuel tanks.

This technical solution describes the normal operation of one of the possible variants of the autonomous on-board descent system (ABSS) as part of the operating system. As follows from this patent, the following basic systems are part of the ASCS:

- the system of evaporation (gasification) of non-producing fuel residues in the tanks of the operating system with its own additional reserves of fuel for the production of hot gases for evaporation (gasification),

- gas rocket propulsion system,

- control system.

At the LCI stage, all systems that are part of the ABSS should be tested, with special attention being paid to systems that have not been previously used onboard the LV. Such a system in the composition of the ABSS is the evaporation system of unworked fuel residues in the tanks after the cruise rocket engine is shut down.

The disadvantages of the prototype when applied to the task LCI evaporation systems are as follows, in addition to installing the tested evaporation system on the OS, it is necessary to develop and install on the OS: a) an autonomous four-chamber gas rocket propulsion unit with controlled drives for each camera; b) control and navigation system; c) OS motion control algorithms on the descent trajectory, etc., which, when the behavior of the LCI, evaporation systems are not involved.

The task of carrying out LCIs is to verify the correctness of the proposed technical solutions when designing the evaporation system under conditions close to real.

The solution of the task is achieved due to the fact that in a known method of carrying out LCIs of an onboard system of evaporation of residual liquid fuel in the spent stage tank (OS) of a launch vehicle (PH) with a cruise liquid rocket engine (LRE), based on heating the residual liquid fuel to a temperature phase transition of liquid to steam by supplying heat to the fuel tank with residues of the fuel component and pressurized gas; dumping the resulting vapor-gas mixture from the tank to the environment, additional actions are introduced:

a) testing of the OS evaporation system is carried out in the associated launch of the LV,

b) before starting the launch vehicle, determine the mass of the remaining fuel in the tank, the mass of the pressurized gas, the temperature of the remaining fuel and gas in the tank after the main propulsion rocket is turned off,

C) calculate the required amount of heat required for submission to the tank for evaporation of the remaining fuel in the tanks,

g) after the separation of the OS from the PH perform a thermal effect on the fuel residues in the tank OS,

e) the hot steam-gas mixture formed in the fuel tank is discharged through the drain valves without creating disturbing moments on the operating system,

e) when the OS section of the maximum velocity head on the descending atmospheric section of the descent trajectory, the magnitude of the boost pressure in the OS tank is ensured from the condition of the structural strength of the tank, and after the passage of this section, the CBC is discharged from the tank,

g) obtaining heat for evaporation of residual liquid fuel, possibly in various ways, for example, by supplying hot gas-generating gas, or by burning energy material in the tank, for example, self-igniting components of fuel, propane and oxygen, etc.

Implementation of the method

In the proposed method, unlike the prototype, a number of terms has been replaced, in particular, the LCI term is used instead of the descent method, which is more suitable for the problem being solved and fully preserves the physical meaning of the prototype. The term “gasification” has been replaced by a more specific and more suitable for the case under consideration - “evaporation”, since the term “gasification” includes a wider range of actions, for example, gasification of a building, gasification of coal, etc. Instead of the term "separated part" the term "spent stage" is used, which is also due to clarification, since to the separating parts of the PH include: spent stages, shutters of the head fairings, interstage transitional compartments, rescue systems, launching devices (cable-mast), etc. It is not gasification products that are considered, but the vapor-gas mixture (PGS), which includes the evaporated liquid component of the fuel, for example, kerosene, oxygen, asymmetric dimethylhydrazine, nitrogen tetraxide, etc., as well as pressurized gases, such as helium, gas-generating gas.

Justification of the expediency of the actions entered

a) testing the OS evaporation system is carried out in the associated launch of the LV, for example, on the OS of the first stage of the LV, due to the possibility of combining the target task of removing the payload into orbit and conducting the LCI of the evaporation system. In addition, the operation of the evaporation system begins after the separation of the OS from the PH. Practically, the LCI process does not affect the main onboard PH systems;

b) prior to launching the PH, determine the mass of fuel remaining in the tank, the mass of pressurized gas, the temperature of fuel residues and the gas of pressurization in the tank after switching off the cruise rocket engine, which is necessary to estimate the amount of heat supplied to the tank for evaporation of fuel residues. The determination of these values is carried out a priori, i.e. before the flight of the launch vehicle according to the known methods used in the design of propulsion systems, refueling systems. On the other hand, the actual values obtained during the flight of the LV at the moment of shutdown of the LRE (a posteriori) will differ somewhat from the prior ones due to random factors of external atmospheric exposure, variations in the operating parameters of the onboard LV systems, as well as the accuracy of the calculation of working and warranty fuel reserves, residues under withdrawal, etc .; the values of these differences are random and are taken into account on the basis of statistical processing of these differences for each PH.

C) calculate the required amount of heat required to feed the tank to evaporate the remainder of the fuel in the tank. The calculation of the required amount of heat will be calculated based on the heat for heating the mass of fuel to the boiling point and evaporation. To this heat, it is necessary to add heat to the heating of pressurized gas in the tank, and also to take into account external thermal inflows and outflows (radiation of the tank into the surrounding space, to heat the walls of the tank from solar radiation, heat the tank when removing the PH). In the general case, these are traditional thermal calculations, and it should be noted that a priori and a posteriori estimates, unlike the estimates of the mass of fuel, are much closer to each other;

g) after the separation of the OS from the PH perform a thermal effect on the fuel residues in the tank OS

Thermal action means convective heat supply in the form of a mass of hot gases in the tank volume. After turning off the LRE in the OS tank, a state of weightlessness sets in and at the same time, due to the impact of the braking impulse of the LV stage separation system, the impact of the upper stage LRE torch, the elastic deformation of the lower bottom (return from the deflection caused by the overload, to its original state liquid fuel), the destruction of the free surface of the liquid fuel occurs and the fuel in the form of a gas-droplet mixture is in the tank volume (book 2 Trushlyakov VI. Reduction of man-caused impact of rocket engines DSC on the liquid toxic components of rocket fuel on the environment: monograph / V.I. Trushlyakov, V.V. Shalai, I.T. Shatrov, edited by V.I. Trushlyakov.Omsk: OmGTU, 2004. - 220 with.)

The time of onset of heat exposure is selected from the following conditions:

- during the passage of the section of the maximum velocity head create pressure in the OS tank, ensuring its strength,

- the processes occurring in the tank (heating of the fuel and evaporation, heating of the gas, discharge of the OPO from the tank) are completed to a height of about 1-5 km.

- the permissible temperature and pressure of the OPO in the fuel tank is limited by its strength;

e) the hot slate formed in the fuel tank is discharged through the drain valves without creating disturbing moments on the operating system,

The parameters of the CGS discharge system from the fuel tank (mass rate of discharge per process time, discharge rate, direction of discharge from the nozzle) are determined from the following conditions:

- the duration of the process of resetting the ASG from the OS tank (the duration of the OS flight on the trajectory of its descent, the total number of ASG in the tank);

- the use of momentless discharge nozzles of ASG, an example of a momentless nozzle is a nozzle that implements opposite outflows of gas flows with the same rods.

At the subsequent stages, the LCI will implement the process of controlling the movement of the operating system using control bodies in the form of gas jet nozzles instead of using momentless nozzles of the ASG, which will provide a drastic reduction in the areas of the fall areas.

f) obtaining heat for evaporation of residual liquid fuel, possibly in various ways, for example, by supplying hot gas-generating gas to the tank, which is used by traditional chemical inflation systems, (see, for example, kn. 3 Belyaev N.M. Systems of pressurization of missile fuel tanks / NM Belyaev. - M .: Mashinostroenie, 1976. - 336 с), or by burning directly in the tank of energetic material, for example, feeding a self-igniting component into a tank with asymmetric dimethylhydrazine nitric tetraxide (p. 1) or see for example, pr. 4 Baranov DA, Lempert DB, Trushlyakov V.I., Shatrov Ya.T. Development of the on-board evaporation system for non-producing residues of liquid fuel in the tanks of the separating part of the PH stage // Astronautics and Rocket Engineering, 2017, 6 (99) p. 93-103, where it is proposed to receive heat directly in the tank with residues of liquid kerosene, propane and oxygen, and to obtain heat in an oxygen tank, burn propane gas directly in the oxygen tank with oxygen vapor in the tank (~ 20% of oxygen residues are in the gas phase, because by the time the LRE is switched off, oxygen in the tank is in the boiling oyanii, since the temperature in the tank is ~ 90K).

The use of the proposed technical solution will allow conducting the LCI stage of the on-board evaporation system of the autonomous on-board OS descent system in the associated launch of the LV, ensuring regular operating conditions at minimum cost. It is also proposed to carry out the subsequent stages of the LCS of the ABSS created (testing the control system, the gas-jet stabilization and orientation system) in the associated launch of the LV, but already taking into account the developed evaporation system and the developed methodical approach of using the associated launches of the PH.

Claims (2)

1. The method of carrying out flight design tests of the onboard evaporation system of residual liquid fuel in the spent stage tank (OS) of a launch vehicle (PH) with a cruise liquid rocket engine (LRE), based on heating the residual liquid fuel to the phase transition temperature to steam by supplying in the fuel tank with the remnants of the component of the fuel and gas of pressurization of heat, discharge of the resulting vapor-gas mixture (CBC) from the tank into the environment, characterized in that the development of the specified evaporation system is carried out in the associated launch of the PH and, before launching the PH, determine the mass of fuel remaining in the tank, the mass of pressurized gas, the temperature of residual fuel and pressurized gas in the tank after the main propulsion rocket is turned off, the required amount of heat required to feed the remaining fuel in the tank to evaporate after PH exercise thermal effects on fuel residues in the tank OS, and formed in the fuel tank, the hot gas mixture is discharged through the drain valves without creating disturbing moments on the OS, while passing through the section of the maximum velocity nap ra is pressurized in the tank operating ensuring its strength, the processes occurring in the tub is completed up to a height of the order of 1-5 km, and the values of ASG temperature and pressure in the fuel tank based on the limit of his strength. 2. The method according to p. 1, characterized in that the obtaining of heat for evaporation of residual liquid fuel is carried out in various ways, for example by supplying hot gas-generating gas, or by obtaining gas directly in the tank.