Close-Collaborative Experimental and Computational Study of a Dual-Mode Scramjet Combustor

Abstract

Advanced computational models of hypersonic air-breathing combustion processes are being developed to better understand and predict the complex flows within a dual-mode scramjet combustor. However, the accuracy of these models can only be quantified through comparison to experimental databases. Moreover, the quality of computational results is dependent on accurate and detailed knowledge of the combustor inflow and boundary conditions. Toward those ends, this paper describes the initial results of a unique, close collaboration of experimental and computational approaches. Detailed computational fluid dynamics (CFD) and finite element thermal-structural analyses (FEA) have been performed throughout the design and implementation of a direct-connect scramjet combustor operating at steady state during long duration testing on the order of an hour or more. The test-section hardware has been designed to provide numerous access points for optical laser diagnostic measurements. Measurement locations include the inflow plane to the scramjet combustor as well as several locations downstream of the fuel injector. In addition, static wall pressures and temperatures are measured at numerous points along the fuel injector side of the scramjet flowpath. Initial CFD calculations were used to generate detailed thermal boundary conditions that were then applied to a non-linear, thermalstructural finite element model of the test-section. The calculated temperatures and thermal deformations are evaluated and validated against experimental measurements. Significant results described in this paper include experimentally measured static wall pressure and temperature data, Stereoscopic Particle Image Velocimetry (SPIV) and focused schlieren imaging. Validated finite element calculations of temperature in the test-section hardware, and temperature maps of the flowpath boundaries are also presented. CFD results are discussed in a separate paper.

Large-Eddy/Reynolds-averaged Navier-Stokes Simulation of a Dual-Mode Scramjet Combustor

“…This model solved for wall temperatures based on facility parameters and assuming all walls were made of stainless steel coated with a thin layer of zirconia. More recently, thermal response analyses carried out by Bob Rockwell of UVa [14] using thermal inputs extracted from NCSU's RANS results have determined that it is appropriate to set wall temperatures to fixed values (discussed further in the next section).…”

Dual-Pump CARS Measurements in the University of Virginia's Dual-Mode Scramjet: Configuration "A"

“…13,14 Figure 1 presents a schematic of the dual-mode scramjet flow path that was used for the CARS measurements. 5 The flow path consists of a Mach 2 facility nozzle that is directly coupled to a rectangular combustor. The combustor is 25.4 mm × 38.1 mm (1" × 1.5") in cross section at the entrance.…”

Dual-Pump CARS Measurements in the University of Virginia's Dual-Mode Scramjet: Configuration "C"

“…Previously we have reported on an extensive CARS data base acquired in configuration "A" of the scramjet. 9,10 Computations of this flow field using Reynolds-averaged Navier-Stokes and large eddy simulation methods and comparisons to the configuration A CARS measurements are reported in Ref. 11.…”