Engine stability scaling method

Abstract

The invention discloses an engine stability scaling method. The method includes the steps of: determining a global parameter, a geometrical parameter, a propellant parameter and a nozzle injection parameter of a full-scale engine; determining a complete combustion length of fuel gas of a combustor of the full-scale engine; determining propellant category, temperature before injection, a mixing ratio and scaling combustor pressure of a scaling engine; determining a scaling dimension r; performing a combustion flow filed similarity design; performing a stability scaling design; and reckoning the full-scale engine according to stability evaluation parameters of the scaling engine. By adoption of the abovementioned method, similar conditions of two combustion flow fields can be well satisfied. Combustor pressure is selected properly, so that a liquid propellant is in a super-critical state, thereby truly representing characteristics of mixed flow fields inside the full-scale engine. Compared with the full-scale engine, both mass flow and combustor pressure are greatly reduced, the structure is simple, operation is easy, and cost is relatively low.

Description

technical field [0001] The invention relates to a scaling method for a rocket engine, in particular to a scaling method for engine stability. Background technique [0002] High-frequency unstable combustion is an important issue in the development of rocket engines. It will cause high-frequency oscillations in the combustion chamber of the engine and a sharp increase in local temperature, burn through the injector head panel or the inner wall of the combustion chamber, and cause the combustion chamber to explode. and other serious consequences. Due to the complexity of the mechanism of high-frequency combustion instability, there is no good way to prevent instability. The most important method is to verify the stability margin of the adopted structural parameter factors through experiments. [0003] The most accurate test is the full-scale test, that is, the test is carried out on a test machine of the same size as the prototype engine. The test results are accurate and rel...

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Problems solved by technology

The second type is specially designed for certain specific oscillation frequencies of the full-scale engine, and the frequency response characteristics of the nozzle are investigated. Since the geometry of the combustion chamber is quite different from that of the full-scale engine combustion chamber, it is difficult to ensure that the flow field is similar and the structure is relatively similar. complex

[0011] To sum up, it can be seen that these two scaling test design methods are not strictly similar scaling design, but only simulate some aspects that affect stability. Due to the above limitations, the above two methods are difficult to target combustion overall similarity study

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