Heat protection method for injection support plate of scramjet engine by utilizing sweat and impingement cooling

Abstract

The invention relates to a heat protection method for an injection support plate of a scramjet engine by utilizing sweat and impingement cooling. The method includes the following steps that (1) a high-temperature-resistant material is used for making the injection support plate of a microporous structure, a supporting rib is arranged in the injection support plate and partitions the same into a front cavity and a rear cavity, impingement pores communicated with the front and rear cavities are formed in the supporting rib, and a fuel pipe of the scramjet engine is communicated with the rear cavity of the injection support plate; (2) by the process that fuel seeps out of pores of the injection support plate of the microporous structure, convection heat transfer is carried out forcedly to remove heat on the surface of the injection support plate, and the fuel seeps out of the surface of the injection support plate to form a film layer so as to block heat transfer of the mainstream to the injection support plate; (3) the fuel is injected from the rear cavity to the inner surface of the front cavity via the impingement pores in the supporting rib so as to perform convection heat transfer with the inner surface of the front cavity, and strength of the injection support plate is enhanced by the aid of the supporting rib in the injection support plate. Heat protection effect on the injection support plate is realized by combining the concept of impingement cooling and utilizing the fuel as a cooling agent according to porous medium characteristics, and the method can be widely applied to heat protection of injection support plates of scramjet engines in various Mach working ranges.

Description

technical field [0001] The invention relates to a thermal protection method for a high-temperature wall surface, in particular to a thermal protection method for an injection support plate of a super-combustion engine by sweating and impact cooling in a high-temperature and high-speed airflow. Background technique [0002] A scramjet is a ramjet in which fuel is burned in a supersonic airflow. When hydrocarbon fuel is used, the flight Mach number of the scramjet engine is usually below 8, and when liquid hydrogen fuel is used, the flight Mach number can reach 6-25. like figure 1 As shown, the supersonic or hypersonic air flow decelerates to a lower supersonic speed in the inlet section and the isolation section and enters the combustion chamber. The gas is discharged through the expansion nozzle section. Since the residence time of the fuel in the combustion chamber is only a few milliseconds, the traditional way of injecting fuel on the wall of the combustion chamber has...

AI Technical Summary

Problems solved by technology

Since the residence time of the fuel in the combustion chamber is only a few milliseconds, the traditional way of injecting fuel on the wall of the combustion chamber has the disadvantage of short penetration distance, which makes it difficult to achieve effective mixing between the fuel and the high-speed mainstream, which affects the ignition and combustion of the fuel.

[0003] The injection branch plate structure is a common device in the combustion chamber to realize the effective mixing of fuel and high-speed mainstream. The fuel is injected from the injection hole on the injection branch plate and mixed with the high-speed main flow to overcome the incident penetration The disadvantage of short distance, but at the same time, the stagnation of the hypersonic airflow on the surface of the injection strut will cause serious aerodynamic heating, and the injection strut, especially its leading edge, is extremely prone to ablation damage. It is estimated that the aircraft will fly at Mach number 8 When flying at an altitude of 27km, the total temperature of the high-temperature gas flowing through the combustion chamber can reach more than 3000K, which is close to the maximum cooling capacity of the forced convection cooling of the fuel currently used. A more effective active cooling method must be used to reduce the surface temperature of the injection support plate

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