An Experimental Study of a Hypersonic Wind-Tunnel Diffuser

Abstract

AMTSACTResults of a variable-area diffuser investigatkm m the continuous IS-by lS-an. Naval Ordnance Laboratory Hypersonic Tunnel No. 4 are presented. A brief introduction discusses previous supersonic diffuse* work. The diffuser investigated and the eipcsuneutal technique are then described. The results show that air condensation in the test section at Ugh Mach Numbers'has only a minor effect on diffuser performance. Data on overall ptmmn ratios for starting and maintaining hypersonic flow for a number of diffusu configurations are presented. The test Mach Numbers rang* from 6.9 to 9A. Prom these data, a diffuser with a stagle-peaktd throat and a three-decree plane wall divergence aft of the throat was selected as most practical. The pressure lotwed by this optimum diffuse* varies, depending on Mach Number, from 1.8 to 2 3 times that movered by a pilot (or impact) tube operated at the teat section Mach Number. Data on pusstim diet rirwit inn measurements throughout the ooxzk and diffuser, spark scMlsrea photographs of diffuse* flow, and data on Reynolds Nusrher effects are also given. Finally, these data an oumpaiad with those of other investigator* and with

Low-Density Hypervelocity Wind Tunnel Diffuser Performance

“…The geometric consideration for high NRe has been well summarized (Ref. 64,66, and 55) by many investigators, but very little information is available at low NRe. Due to the limited variety of geometric configurations tested, only a few conclusive facts on geometry effects were presented by Potter (Ref.…”