Progress in research on mixing techniques for transverse injection flow fields in supersonic crossflows

Abstract

The transverse injection flow field has an important impact on the flowpath design of scramjet engines. At present a combination of the transverse injection scheme and any other flame holder has been widely employed in hypersonic propulsion systems to promote the mixing process between the fuel and the supersonic freestream; combustion efficiency has been improved thereby, as well as engine thrust. Research on mixing techniques for the transverse injection flow field is summarized from four aspects, namely the jet-to-crossflow pressure ratio, the geometric configuration of the injection port, the number of injection ports, and the injection angle. In conclusion, urgent investigations of mixing techniques of the transverse injection flow field are proposed, especially data mining in the quantitative analytical results for transverse injection flow field, based on results from multi-objective design optimization theory.

Numerical investigation of characteristic frequency excited highly underexpanded jets

“…In particular for a scramjet, ultrafast mixing of fuel with oxidizer is required due to the limited time and length available in the combustor. Additional performance factors of a scramjet, such as the combustion efficiency, combustion stability, and flammability limits, are all strongly affected by the mixing process between fuel and air [8][9][10].…”

“…On the other hand, parallel injection has lower total pressure losses and provides enhanced thrust, but its penetration into the cross stream is generally poor [13]. Due to inherent drawbacks of the two traditional injection techniques, several passive control techniques have been suggested to enhance fuel-air mixing at high speeds [8,9,14]. Cavity-based injections [15], step-based [16] or strut-based [1,17] injections, and swept ramp injectors [18,19] are some of the wellstudied designs.…”

Supersonic mixing augmentation mechanism induced by a wall-mounted cavity configuration

“…The hydrogen plume issued from two pylon-type injectors. Huang and Yan (2013) gave a detailed review of transverse injection schemes in supersonic flows, and found that the mixing process in the transverse injection flow field is influenced by many geometric parameters, suggesting that it is a multi-objective problem. Vinogradov et al (2007) provided an overview on the pre-injection scheme involved in a pylon, and concluded that the pylon is a useful tool to enhance the mixing process in a transverse injection flow field.…”

Investigation of injectant molecular weight effect on the transverse jet characteristics in supersonic crossflow

“…However, because of the supersonic crossflow, the residence time of fuel is too short to achieve the complete mixing between injectant and crossflow [2]. To improve the mixing efficiency between the fuel and air, injection strategies in scramjet engines have been investigated extensively , such as transverse jet [3][4][5][6], ramp jet [7,8], aerodynamic ramp jet [9,10], pylon jet [11,12] and strut jet [13].…”