Drags in Scramjet Engine Testing: Experimental and Computational Fluid Dynamics Studies

Abstract

No-fuel internal drag of a side-compression scramjet engine was evaluated by using two one-e fth-subscaled models, one forwall pressure measurement and theother forforce measurement under conditionsof a e ight Mach number of 4. The pressure and frictional drags in various parts of the models were estimated from these windtunnel tests. Comparison between the pressure measurement and the force measurement revealed that the drag derived by these wind-tunnel tests agreed within 5%. After examining the consistency between the pressure and the force experiments, these results were used to calibrate a newly developed computational e uid dynamics code. The frictional drag and the heating rate on the engine internal walls were evaluated with the unstructured-grid code to be compared with those obtained from the one-e fth-subscale model and the full-scale engine. The total drag coefe cient of the scramjet engine, including the installation drag, was found to be 0.281 and the internal drag coefe cient was found to be 0.093. Consequently, two-thirds of the total drag measured in engine testing in the Ramjet Engine Test Facility was produced by the external e ow over the engine module. Subtracting the external drag, the internal performance delivered by the H 2-fueled scramjet engine is discussed.