Performance Study On Flameholding Strut With Cooling Structure In Supersonic Combustor

Scramjet has been an advanced research hotspot in major military power and space power for its high speed, high specific impulse and large cruise range, however, the speed of the incoming flow of the combustor is too high to hold the flame. A new flame holding strut with cooling structure is proposed in this study for the combustor which use strut to make combustion stable, a plasma ignition system is also designed.First, the time of air-flow used to judge the ability of strut to create recirculation zone is proposed in the study, and a program is written to plot streamline and calculate the time of air-flow. The flow field of a strut without swept is analyzed, and the relationship between the position of flow field and the time of air-flow is expounded. The law between the strut structure parameters and the time of air-flow is researched and the principle of design for the flame holding strut is put forward.Second, a new thermal protection method by opposing jet for the high temperature air causes the leading edge of a scramjet strut significant erosion and damage is proposed. The effect of different total pressure of cooling fuel on the strut flux is calculated and the mechanism how opposing jet can reduce surface flux is point out, and the effect of opposing jet on aerodynamic parameter of combustor is also analyzed. In the last, the calculation shows that appropriate working parameters not only can reduce flux but also increase total pressure loss slightly.Thirdly, a saw tooth strut and a plasma ignition system(short for PIS) are designed between the strut structure parameters and the time of air-flow. The flow field of saw tooth strut without kerosene and with kerosene are calculated, and the results are compared with common struts. A primary design of opposing jet cooling is presented and the strut flux distribution is calculated by 3D flow field. A flame holding strut with opposing jet cooling is determined.In the last, the test of flame holding strut and plasma ignition is carried out on the supersonic test facility. The performance test of PIS is carried ou t in common environment, then the saw tooth strut and weld gun, PIS are finished on the test facility, and the pressure data are compared with common strut which length is 8mm. The results show that the strut can work and PIS can build the combustion.