Exploratory Simulations of the HIFiRE 2 Scramjet Flowpath

Abstract

Steady-state Reynolds Averaged Navier-Stokes (RANS) simulations of a hypersonic airbreathing propulsion system have been performed to examine key aero-propulsive phenomena, including the effects of turbulence, heat release, and viscous/inviscid interactions. The simulations are anchored in the HIFiRE-2 flight test and supporting ground tests performed at the NASA Langely Arc Heated Scramjet Test Facility. Through comparison to experimental data from the ground tests, initial simulations focus on formation of grids and calibration of heat release models, including volumetric heat release as well as a reduced-order bi-component ethylene-methane combustion model. For the ground test simulations, unfueled, volumetric heat release, and the reduced order combustion model results are compared to experimental data and each other. Flight test simulations are compared to ground test simulations, and the similarities and differences are evaluated. In doing so, a foundation is prepared for forthcoming time-accurate simulations of in flight mode transition and unstart.

Effect of Initial Conditions on Simulations of a Scramjet Flowpath

“…The simulation approach is the same as has been employed in our previous works (see [16,17,22,23] for details). Briefly, the simulations are performed with the unstructured CFD++ code.…”

Compressive sensing adaptation for polynomial chaos expansions

“…UQ for supersonic reactive flows using large eddy simulations (LES) has only recently become feasible owing to both algorithmic advances and increasing computational power and resources. This development has allowed researchers to explore beyond the commonly used Reynolds-averaged Navier-Stokes (RANS) model [64]. Even with the use of RANS, hybrid RANS/LES, or Detached Eddy simulations (DES) [48], construction of accurate response surfaces for QoIs faces insurmountable challenges due to the large number of simulations required to explore the often high-dimensional space of uncertain model parameters.…”

Exploiting active subspaces to quantify uncertainty in the numerical simulation of the HyShot II scramjet

“…The trade-off is that turbulence is now modeled; the accuracy of the result depends strongly on the accuracy of the turbulence model. RANS represents the most practical approach for performing UQ of the HyShot II system, and in general RANS is the most common approach used by hypersonic vehicle designers for simulating turbulence in their systems [29,66]. Pečnik et al [46] and Terrapon et al [55] give comprehensive treatments of the discretization and numerical implementation of the corresponding physical models.…”