Experimental and Numerical Performance Analysis of a Self-Starting Three-Dimensional Scramjet Intake

Abstract

In this work, a three-dimensional intake model was investigated in a blowdown wind tunnel and results were compared and complemented with Reynolds-averaged Navier-Stokes simulations. The intake model was equipped with a movable cowl with which the internal contraction ratio was set to the self-starting limit. Three different conditions were investigated: first, a v-shaped cowl geometry at a freestream Mach number of seven; second, a straight cowl geometry at a freestream Mach number of seven; and, finally, a v-shaped cowl geometry at a freestream Mach number of six. Furthermore, a one-dimensional postanalysis was performed to calculate overall engine parameters from stream-thrust-averaged intake performance parameters. Numerical results were within the experimental uncertainty, except for small displacements near separation regions. The mass capture ratio of the v-shaped cowl was slightly higher as compared to the straight cowl. When increasing the Mach number from six to seven, the specific impulse dropped from 2561 to 2100 s, respectively. For the Mach 7 configurations, a maximum sustainable backpressure ratio of approximately 115 was measured. For the Mach 6 case, the maximum sustainable static backpressure ratio dropped to about 85. The maximum sustainable backpressure to operating backpressure ratio was around 4:1, and it was independent of the Mach number.

Modified Kantrowitz Starting Criteria for Mixed Compression Supersonic Intakes

“…All approximations were within 3% of the semiempirical limit; the empirical limit with C 1 1.5 and the polynomial fit were even within 2%. For Mach [15] Smart and Trexler [16] Jacobsen et al [18] Goldberg and Hefner [9] Emami et al [19] Smart and Tetlow [17] unfilled symbols: unstart Fig. 7 Self-developed semiempirical relation in comparison with results on intake starting obtained from the literature.…”

“…In a previous study, we performed starting experiments in a hypersonic blowdown wind tunnel, known as H2K, at the German Aerospace Center (DLR) in Cologne with a three-dimensional intake model [4,14], and we complemented the analysis with CFD [15]. The model was equipped with a movable cowl, permitting variable internal contraction so that, during an experiment, the CR i was slowly decreased until intake starting occurred.…”

Study on Three-Dimensional Inner Flow Field Characteristics and Performance of Scramjet

“…Researchers have carried out a large number of experiments and numerical simulations on the structure optimization, performance evaluation, flow and combustion calculation of the scramjet engine and its inlet. Effective work [1,2,3,4]. The flow field inside and outside the hypersonic inlet is very complicated and is a typical three-dimensional flow.…”