Numerical Investigation of the HIFiRE-2 Scramjet Flowpath

Abstract

Three dimensional turbulent simulations with combustion modeling are employed to understand fundamental phenomena encountered in the HIFiRE-2 scramjet flowpath. Experimental data from the ground test campaign as well as a grid resolution study is used to validate the results of the simulations. These confirmed results are then leveraged to explain the physics of dual and scramjet-mode operation in a steady sense, including detailed examinations of shock structure, boundary layer separation, and combustion chemistry. Initial results of unsteady simulations are used to investigate the process of mode-transition, and a simplified heat release model is developed and tested. Simulations of the flight test are presented and contrasted with the ground test results to characterize the effects of the inlet on the boundary layer development and internal shock structures. Overall, agreement with ground test results is excellent, and the simulations show highly complex three dimensional structures to be present in the flow. Boundary layer separation induced shock / boundary layer interactions dominate dual-mode operation, while at higher Mach numbers a flameholding effect of the barrel shock from fuel injection is striking. The effects of the inlet are found to be of great importance to accurately model flight tests, however, the same macro-scale effects as observed in the ground test simulations are dominant.

Progress in shock wave/boundary layer interactions

“…14(c) and (d) compares experimental tare (no combustion) and combusting C p values to simulations using the k À ω model and the Taitech-Princeton 2 model (see Ref. [144] for details). Although there are several areas where the comparison may be improved, the simulations reproduce the main elements in the inlet as well as the pressure rise associated with combustion.…”

“…There are many other features that arise in such flows on sidewalls and in corners, interactions with injection jets, flame devices and so on, whose description may be found for example in Refs. [142][143][144][145][146][147][148].…”

“…A recent effort by Yentsch et al [144] examines the effect of inlet SBLI by first anchoring results to the ground tests [24,151] and then leveraging the proven model to analyze the flight test. Fig.…”

Experimental Investigation of Supersonic Model Combustor with Distributed Injection of Supercritical Kerosene

“…In dual-mode scramjet combustors, using axial staging of fuel injection is a common approach to control dualmode operation. There have been a series of studies on the effects of fuel-injection configuration and fuel flow rate on the flowfield and thrust performance of scramjet combustors [11][12][13][14][15]. The numerical simulation of dual-mode scramjet devices has been approached by some researchers [13,16].…”

“…However, a further increase in the fuel flow rate and the pressure rise with the singlestage injection was limited by the upstream propagation of boundary-layer separation due to excessive heat release [10]. The idea of staged fuel injection [11][12][13] uses the combustion of an upstream-injected fuel to improve the mixing and burning processes of the downstream-injected fuel while still keeping the fuel flow rate through the upstream injectors below the allowable value. In this case, better pressure distributions and higher thrust could be attained.…”