Experimental and numerical study of heat transfer on a blunt body in dusty hypersonic flow

The measurement technique and results of experimental investigation of heat transfer on the frontal surface of spheres in a hypersonic dusty gas flow with particles with the mean diameter d = 0.1% 160 pm are presented. The experiments were carried out in a short-duration wind tunnel for the carrier-phase Mach number M = 6.1, the total pressure P,= 2.1~33 bar, the stagnation temperature T, = 570 “K, and the Reynolds number based on the free-stream parameters and the model radius Re,a = (4+500).103. The models were four aluminum spheres with radius R = 3, 6, 12, and 24 mm, installed on the same suspension arm. Si3N4, SiOz, Fe203, Cr203, and Fe particles were used as the dispersed phase. In most of the tests, the carrier phase was air, in several tests the carrier phase was N2 and COz. The free-stream particle mass concentration was varied on the range c = 0+25 %. The experiments demonstrate that the presence of even very small particles (d=0.12 +O. 15 pm) in the free stream results in a significant increase in the heat flux to the stagnation region of the model. On the basis of numerical calculations, the limits of the regime of absence of particle deposition on the body surface in the space of nondimensional parameters are found. It is shown that most of the experimental results for small SiOz particles correspond to the no-deposition regime. These experimental results are compared with numerical calculations based on the laminar two-phase boundary layer theory explaining the heating augmentation by particle accumulation in the boundary layer. 1 ’ ’ * Ph. D Senior Reseacher, Hypersonic AeroThermody&mics Department. **Dr. Sci., Head Reseacher, Lab. of General Aerodynamics. “Copyright @ 1999 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.” In the experiments performed in full dark, a slight glow near the surface of the models, apparently caused by the presence of electric charge on the particles, was registered.