RU2476713C2 - Method of cleaning liquid-propellant rocket engine combustion chamber inner surface - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: proposed method comprises feeding cleaning material, collecting cleaning products and their recovery or disposal. In compliance with this invention, said inner surface is subjected to effects of two-phase jet consisting of gaseous and dry cleaning materials. For this, acceleration Venturi nozzle is fitted into combustion chamber to displace there inside about its axes in horizontal and vertical directions. Compressed air is used as gaseous material. Cleaning materials dry particles or granules are ejected by compressed air into flow and, via acceleration device, toward combustion surface cleaned surface. Note here that after removal of dirt from said surface, dry cleaning material is evaporated. Said dry cleaning material represents dry ice bits or granules. Removed particles of carbon, soot and oxides are sucked off by dustless cup or vacuum cleaner.

EFFECT: better cleaning.

3 cl

Description

The invention relates to the field of rocket propulsion, in particular to the production and testing of liquid reusable rocket engines running on fuel, which during combustion forms carbon deposits on the inner surface and parts of the combustion chamber.

In preparing the engine for restarting, among other things, it is necessary to clean the deposits from the inner surface of the combustion chamber.

A known method of cleaning the inner surface of the combustion chamber of a liquid rocket engine, including the supply of cleaning material, the collection of cleaning products with their subsequent disposal (see RU 2412086, 02.20.2011).

An object of the invention is to increase the degree of purification of complex geometric and relief surfaces of parts and components of the combustion chamber.

The problem is solved due to the fact that the method of cleaning the inner surface of the combustion chamber of a liquid propellant rocket engine, including the supply of cleaning material, the collection of cleaning products and their subsequent disposal, according to the invention, affects the surface to be treated with a two-phase jet consisting of a gaseous and cleaning material of dry composition, for of this, an accelerating Venturi nozzle is introduced into the combustion chamber of the rocket engine, mounted on the device and moving inside the combustion chamber around its axis in the horizontal and vertical directions, compressed air is used as a gaseous material, particles or granules of a dry-cleaning material due to ejection created by a stream of compressed air enter the stream and are thrown out through the booster nozzle towards the cleaned inner surface of the combustion chamber, and after separation contaminants from the treated surface, the cleaning material dry composition evaporates. As a dry cleaning material, crumbs or granules of dry ice (solid carbon dioxide) are used.

The removed particles of soot, soot and oxides are sucked off with a dust-free nozzle or vacuum cleaner.

Particles or granules of dry ice in the proposed method perform cleaning due to the high kinetic energy, low temperature of dry ice and sublimation into a gaseous state of particles or granules of dry ice at the moment of contact with the surface being cleaned. With large, difficult to remove deposits of carbon deposits in the proposed method, it is possible small (3-5% by weight of dry ice) adding to the dry ice various dry cleaning additives (softeners). To mechanize and collect the products of the proposed cleaning, an industrial vacuum cleaner with a special nozzle or a dustless nozzle specially designed according to the profile of the internal surface of the combustion chamber of liquid rocket engines is used.

Another difference is that there are no traces of fuel on the cleaned surface.

For the proposed method of cleaning, you must perform the following operations:

- liquid rocket engine is fixed in a vertical position;

- a particle dosing and dispersal unit is driven into the engine, into which ground or granular dry ice (carbon dioxide) is loaded;

- compressed air with a pressure of 4-10 ati is supplied to the particle dosing and acceleration unit. (selected experimentally) and a flow rate of 4-7 cubic meters / min (selected experimentally);

- an accelerating nozzle of the VENTURI type is introduced into the combustion chamber of the rocket engine on the device, which is connected to the particle dosing and acceleration unit with a heat-insulated, frost-resistant hose. An accelerating nozzle of the VENTURI type can have a configuration as different as necessary, creating a torch direct or deployed 90-180 degrees.

The mechanized cleaning process is as follows:

- particles of ground or granular dry ice due to the ejection created by a stream of compressed air fall into the stream and reach speeds in excess of 150 m / s in the accelerating nozzle, and are thrown out through the accelerating nozzle towards the cleaned inner surface of the combustion chamber;

- particles or granules of dry ice at the moment of contact with the surface being cleaned create a “thermal shock”, causing freezing and cracking of soot, penetrate into cracks and, due to various coefficients of linear expansion of soot and material of parts and nodes of the combustion chamber, reduce adhesion of soot to the substrate;

- upon impact, particles of ground or granular dry ice are sublimated into gas (carbon dioxide) with an expansion coefficient of 800 times. The expansion of gas in cracks leads to an explosive effect and the complete removal of soot from the surface of the combustion chamber;

- an accelerating nozzle of the VENTURI type, mounted on the device, moves inside the combustion chamber around its axis in the horizontal and vertical direction along a predetermined path;

- An industrial vacuum cleaner with a special nozzle or a dustless nozzle attached to the device collects cleaning products - carbon deposits for the purpose of subsequent disposal.

Claims (3)

1. The method of cleaning the inner surface of the combustion chamber of a liquid propellant rocket engine, including the supply of cleaning material, the collection of cleaning products with their subsequent disposal, characterized in that they act on the treated surface with a two-phase jet consisting of a gaseous and cleaning material with a dry composition, for this purpose, into the combustion chamber a rocket engine introduces an accelerating venturi nozzle mounted on the device and moving inside the combustion chamber around its axis in the horizontal and vertical directions x, compressed gas is used as a gaseous material, particles or granules of a dry-cleaning material due to the ejection created by a stream of compressed air enter the stream and are thrown out through the booster nozzle towards the cleaned inner surface of the combustion chamber, after which contaminants are separated from the treated surface dry cleaning material evaporates. 2. The method according to claim 1, characterized in that as a dry cleaning material used crumbs or granules of dry ice (solid carbon dioxide). 3. The method according to claim 1, characterized in that the removed particles of soot, soot and oxides are sucked off with a dustless nozzle or vacuum cleaner.