Effect of parallel-jet addition on the shock train characteristics in a central-strut isolator by detached eddy simulation

• Published in: International journal of heat and mass transfer Vol. 114; pp. 1159 - 1168
• Main Authors: Xue, Rui, Wei, Xianggeng, He, Guoqiang, Hu, Chunbo, Tang, Xiang
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.11.2017; Elsevier BV
• Subjects: Aerodynamics; Boundary layer; Central-strut isolator; Computational fluid dynamics; Computer simulation; Detached eddy simulation; Jets; Mathematical models; Normal shock waves; Numerical analysis; Oblique shock waves; Primary jet addition; Shock train; Three dimensional models; Velocity; Vortices; Shock train; Central-strut isolator; Primary jet addition; Boundary layer
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2017.06.074

•Effect of high-velocity jets addition on shock train characteristics in RBCC was studied.•The shock train was transformed into two parts at high back pressures.•One part was the oblique shock waves and another was the quasi-normal shock waves.•With the rocket jet addition, the vortexes gradually break up to small scales at downstream. For the Rocket-Based Combined-Cycle (RBCC) engine, the addition of primary rocket jets makes both the flow field and the shock train structure more complicated. In this study, a three-dimensional Detached Eddy Simulation (DES) modeling was employed for the numerical analysis of a full-scale central-strut isolator. The characteristics of shock train for the flight Mach 3 were studied. As a result, under the effect of central high-velocity central jets and different back pressures, the structure of shock train could be changed. At the low back pressure, the expansion wave originated from the trailing edge of the central strut still existed, and one X-type shock wave was formed at downstream. Then the strength of the subsequent shock waves between the parallel-jets and the wall in shock train gradually decays. As the back pressure increased, the leading edge of the shock train moved upstream. The shock train was then transformed into two parts: one part was the oblique shock wave generated in the strut section; another was the quasi-normal shock waves formed in the mixing section within the region between the shear layer and the parallel jets. The origination of the first shock wave could cause the generation of the vortexes in the isolator. With the parallel-jet addition, as the vortexes were transported downstream, they broke up into small scales and in more random orientation at the back wall of the central-strut.