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Supersonic Particle Probes

其他書名	Measurement of Internal Wall Losses
出版	Defense Technical Information Center, 1988
URL	http://books.google.com.hk/books?id=IPSJMAEACAAJ&hl=&source=gbs_api

註釋The operating characteristics of supersonic particle probes were investigated. The characteristics such as internal wall deposition, pressure recovery, and ease of operation and construction were examined. Three basic probe designs were tested in a cold flow experiment designed to simulate the hot, hostile environment of rocket and jet engine plumes. The probe designs consisted of two internal shock probes (Dehne and Colket probes) and one external shock probe (McGregor probe). In the internal shock probes, the compression from supersonic to subsonic flow occurred either in a constant area throat (Dehne) or at a sudden expansion (Colket). In the external shock, or McGregor probe the shock was positioned slightly outside the entrance of the probe. From deposition studies performed on the probes, three factors were found to enhance deposition. These factors were (1) shock-boundary layer interaction, (2) particle-boundary layer interaction, and (3) stagnation zones at sudden expansions. The probe with the lowest deposition was a McGregor probe with a 2.0-deg divergence angle. Using test particles with diameters of 1.0, 1.5, 2.0, and 2.5 micron, the average losses in the McGregor probe were 14 percent, whereas in the Colket and Dehne probes, the losses were 18 and 22 percent, respectively. A correlation was developed to predict the deposition (E) in the McGregor probe using Willeke's dimensionless parameter (Omega): E = 1011 Omega + 1.55. (jhd).