Evaluation of vaned diffuser performance applicable to chemical laser pressure recovery systems

摘要

Abstract: In order to operate weapon-level chemical lasers, suchas DF or COIL, or test articles, such as the Alpha HFchemical laser, in the atmosphere it is necessary torecover as much of the velocity component of the flowand convert it to pressure as possible. This conversionis accomplished through diffusers which decelerate theflow from supersonic to near zero velocities.Subsequent pressure increases to atmospheric levels, ifrequired, are normally accomplished with ejectors. In asize limited carrier vehicle or test area it isdesirable to design diffusers which are as small andcompact as possible and still maintain optimumperformance. One method of reducing the size ofsupersonic diffusers is to employ vanes to reduce theeffective inlet duct dimension (D) and thus the length(L), since L/D $EQ Constant for a given inlet Machnumber. This paper presents a tutorial on diffusertheory as well as experimental results from both TRWand UTRC on vaned diffuser performance. The resultsemphatically show that vanes are only effective whenthey reduce the inlet duct dimensions perpendicular tothe limiting boundary layer. !3