Drags in scramjet engine testing: Experimental and computational fluid dynamics studies

No-fuel internal drag of a side-compression scramjet engine was evaluated b y using two one-fifth-subscaled models, one for wall pressure measurement a nd the other for force measurement under conditions of a Eight Mach number of 4. The pressure and frictional drags in various parts of the models were estimated from these wind tunnel tests. Comparison between the pressure me asurement and the force measurement revealed that the drag derived by these wind-tunnel tests agreed within 5%. After examining the consistency betwee n the pressure and the force experiments, these results were used to calibr ate a newly developed computational fluid dynamics code. The frictional dra g 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-fif th-subscale model and the full scale engine. The total drag coefficient of the scramjet engine, including the installation drag, was found to be 0.281 and the internal drag coefficient was found to be 0.093. Consequently, two thirds of the total drag measured in engine testing In the Ramjet Engine T est Facility was produced by the external flow over the engine module, Subt racting the external drag, the internal performance delivered by the H-2-fu eled scramjet engine is discussed.