Advanced Modeling of New Fuel/Air Mixing Data Sets for Scramjet Applications

Abstract

This paper discusses our analysis of recent high speed fuel/air mixing data sets being generated to support the calibration of RANS turbulence models and the validation of CFD codes used for scramjet combustor simulations. These data sets capture key flow features entailed in scramjet injector design; they use different molecular weight fuels to examine density gradient effects; and, they include data for both flush and in-stream injectors. The experimental data sets, along with the CFD comparisons, for a variety of scramjet relevant cases are incorporated in a web-based, GUI – driven validation tool (CRAVE) which is intended to provide a database of test cases that can be quickly accessed so model modifications can be easily reviewed for effectiveness. To build this database, the test cases are first analyzed with baseline grids and basic turbulence modeling. Improved comparisons are then obtained using adaptive gridding and turbulence model extensions such as scalar fluctuation modeling and density gradient corrections. In this paper, we will briefly discuss the CRAVE database and several of the test cases we are incorporating into it. We will then present “first-pass” results for some of the new data and some turbulence model upgrades that have noticeably improved our data comparisons. The primary goal of this paper is to describe the new validation test cases for fuel/ air mixing and report on progress we are making using improvements to our baseline turbulence model.