RU2498103C1 - Microelectromechanical rocket engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: microelectromechanical rocket engine is made in the form of a structure, from semiconductor silicon crystals, arranged one above another, in one of which there is a combustion chamber with a fuel element, and comprises a unit of fuel ignition with metal conductors. The combustion chamber with the fuel element is made in the form of nanocrystalline porous silicon with depth of not more than 60 mcm, pores of which are saturated by hydrogen and doped potassium nitrate. In the second plate there is a nozzle arranged symmetrically to the nanocrystalline porous silicon and coupled with it via metal conductors.

EFFECT: simplification and cheapening of a process of engine manufacturing, provision of high reliability of an engine according to parameters associated with engine operation: temperatures, mechanical loads, mode of engine operation and provision of normal gas dynamic function as a result of the proposed design and fuel.

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Description

The invention relates to space rocket technology, and in particular to the creation of a new generation of rocket engines

The micromechanical rocket engine is intended for use as a part of space upper stages of nanosatellites.

Known rocket engines containing running on environmentally friendly cryogenic fuel, consisting of liquid oxygen (oxidizing agent) and liquid hydrogen (fuel). This fuel is the most effective at the second stage of the flight, which is due to the increased energy characteristics of liquid hydrogen at a relatively low density due to its low density (see RF patent No. 2397116, January 30, 2009, IPC B64G 1/00).

A solution is also known in which the reactive force for rocket movement is generated by an engine consisting of a working chamber with a nozzle and an element (fuel) using the explosion effect to create reactive force (see Prince Volodina, V.A. Design and Design of Rocket Engines, ed. "Engineering", M., 1971, p. 44).

However, this decision has not been developed.

The closest solution is known, in which the microelectromechanical rocket engine consists of a combustion chamber unit, a nozzle, an igniter, an electric pulse supply unit for ignition and a sealing plate made of single-crystal silicon (US Pat. No. 6,378,292 B1, F02K 9/42, published on 30.04 .2002).

In the assembly process, one of the main operations is filling the combustion chamber unit with paste-like fuel. The assembly process consists of the following technological operations: 1) assembly by gluing; 2) filling with fuel; 3) assembly by UV gluing; 4) fuel filling; 5) assembly by gluing with epoxy resin.

The disadvantages of this engine are: 1) the complexity and high cost of manufacturing individual parts of the engine and their assembly; 2) the need for double introduction of fuel using screen printing (primary fuel and for ignition); 3) low reliability due to the use of standard technological operations and materials that do not withstand high temperatures and mechanical loads associated with engine operation.

The technical problem of this invention is solved: 1) simplification and cheapening of the engine manufacturing process; 2) ensuring high engine reliability in terms of associated engine operation, temperatures, mechanical loads, engine operation mode; 3) ensuring a normal gas-dynamic function due to the proposed design and fuel.

To accomplish this task in a microelectromechanical rocket engine made in the form of a structure of semiconductor silicon crystals located one above the other, in one of which a combustion chamber with a fuel element is made, and contains a fuel ignition unit with metal conductors, a combustion chamber with a fuel element is made in in the form of nanoporous silicon with a depth of not more than 60 μm and, pores, which are saturated with hydrogen and doped potassium nitrate, a nozzle located in the second plate is located adic nanocrystalline porous silicon and joined to it through the metallic conductors.

The invention is illustrated in the drawing, which shows a longitudinal section of a microelectromechanical rocket engine.

The engine contains: a combustion chamber 1 in the form of a layer of nanoporous silicon, an upper plate 2 of single-crystal silicon, a lower plate 3 of single-crystal silicon, a nozzle 4, a metal conductor 5, designed to supply an electrical impulse to ignite the fuel. The combustion chamber 1 is made in a single-crystal silicon wafer 2, and is formed by a region of nanoporous silicon obtained by etching silicon with polishing solutions doped with potassium nitrate. An Laval nozzle 4 is etched into the lower single-crystal silicon wafer. Between them are metal conductors 5.

Monocrystalline silicon wafers are connected, for example, by anodic fit, so that the metal conductor is under a part of nanoporous silicon, and an electrical impulse is applied through it, increasing the temperature in the region of nanoporous silicon. Ignition of a fuel-hydrogen mixture occurs, doped into nanoporous silicon as a result of etching with hydrofluoric acid or polishing solutions, mixed with oxidizing agent-oxygen released during the decomposition of potassium nitrate. The initiated fast exothermic reaction, depending on the flow rate of the resulting gas, leads to the normal expiration of the burnt reaction products and the implementation of the classical gas-dynamic function within ten milliseconds or to an increase in the speed of the shock wave and the creation of a detonation wave exceeding the speed of sound, and an explosion occurring in less than 1 millisecond Given the size and dimensions, the mass of nanoporous silicon, in both cases the effect of reactive controlled motion is achieved.

The device operates as follows: when voltage is applied to the metal conductor 5, the fuel contained in nanoporous silicon 1 is ignited. Combustible gases generated by a quick exothermic reaction break out through the nozzle 4, creating reactive thrust.

Depending on the volume in which nanoporous silicon is obtained, processes are possible that ensure normal quasistationary gas outflow and generation of a detonation wave. The boundary between these two modes of operation is the depth at which single-crystal silicon is etched. Up to 60 microns in depth, the heat of an exothermic reaction and the rate of heat removal through single-crystal silicon provide the normal gas-dynamic function of a microelectromechanical rocket engine.

More than 60 microns of the depth of the obtained nanoporous silicon create conditions for increasing the heat of a quick exothermic reaction, increasing the process temperature by 1.5-2 times to ~ 5000 K and the formation of a detonation wave. When calculating the equations of internal ballistics, the mechanism of formation of shock waves is used.

This device is an ideal solution for small spacecraft in which the size and mass of the engines are critical.

The described microelectromechanical rocket engine can be used for small-sized artificial nanosatellites.

Claims (1)

A microelectromechanical rocket engine made in the form of semiconductor silicon crystals located one above the other, in one of which a combustion chamber with a fuel cell is made, and contains a fuel ignition unit with metal conductors, characterized in that the combustion chamber with a fuel cell is made in in the form of nanocrystalline porous silicon with a depth of not more than 60 μm, the pores of which are saturated with hydrogen and doped potassium nitrate, a nozzle located in the second plate is located tricky to nanocrystalline porous silicon and articulated with it through metal conductors.