Experimental and Numerical Study of Supersonic Flow in Scramjet Combustor in Expansion Tube
Creators: name:  S. GUMRUK TOKGOZ 
name:   B. SUMER 
name:   B. YAZICI 
name:   S. USLU 
Publisher: name: Proceedings of the Aerospace Europe Conference - EUCASS - CEAS - 2023
Year: 2023
Subjects: SCRAMJET
COMBUSTION
SHOCK TUBE

description: Scramjet testing for design is quite unique due to demanding operation conditions that are the natural outcome of the hypersonic flight. The ground testingof scramjetengines is widelyperformedinscramjet test facilities, that have the capabilities to simulate both total enthalpy and total pressure of the incoming air flow. The construction of high mass flow rate blow down, scram jet test facilities need careful planning and respectable amount of investment. Expansion tube facilities, on the other hand, can be constructed with a relatively small investment cost and they can used to simulate these wide range of operating conditions by only changing filling pressures of test sections. In this study TIJBITAK SAGE Expansion Tube Facility (TS-ETF) was modified for investigation of supersonic flow in scramjet combustors and used to investigate the flow inside a scram jet combustor. The main drawback of the expansion tube testing is the effective test time, which is in the order of microseconds, within which the measurements should be taken. Computational Fluid Dynamics tools has been used for the prediction of high-speed flows for about half a century now. Yet the flow physics inside a scram jet combustor is highly demanding because of thin boundary layers, shock formations, turbulent mixing, real gas effects, combustion and their interactions. In this study a commercially available CFD solver is used to numerically investigate the flow inside the scram jet com bustor. Two dimensional and three dimensional, steady Compressible viscous analyses are performed. Effects of different turbulent models on the flow characteristics are investigated A grid sensitivity study is performed for the 2D analyses, the result of which is used for the 3D analyses. The results of the numerical analyses are compared and validated against experimental data. In conjunction with the numerical studies experimental studies are performed for same operating conditions in TS-ETF. Com bustor model is fabricated with optical accesses, which utilizes quartz windows, on three sides to visualize the flow with imaging techniques. Experimental studies are performed for different operating conditions in TS-ETF to investigate shock train and shock/boundary layer interaction in combustor. Static pressure measurements on the top wall of combustor model and Schlieren imaging are used to characterize the flow in com bus tor model. 1. futroduction Operational envelopes of scram jet engines are quite wide. Therefore, the flow within the com bus ti on chamber exhibits a broad range of aerothermodynamic variations. To fully test these conditions on the ground, a test facility capable of operating over a wide range of temperatures, pressures, and Mach numbers are required. In order to determine the turbulence model to be used in the analysis of the scram jet com bus ti on chamber, a literature review was conducted, and it was generally observed that the SST k-m turbulence model is commonly used. Copyright 2023 by First Author. Posted online by the EU CASS association with permission