80-Micron Particle Acceleration in an Expanding Gas.
Interim rept. Feb-Oct 80,
AIR FORCE WRIGHT AERONAUTICAL LABS WRIGHT-PATTERSON AFB OH
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For the purpose of re-entry erosion testing, small particles 80-micron size can be accelerated to high speeds in expanding helium. To provide sufficient residence time of the particles in the flow for an effective acceleration process, the necessary expansion nozzles become very long relative to their throat diameter, with the consequence of incurring considerable wall friction losses. A method is presented for calculating flow expansion with the inclusion of wall friction forces. This method uses a stepwise procedure which allows a ready account of the particle acceleration process. Since extreme high gas temperatures obtained by electric arc heating must be applied to accomplish required gas speeds the expansion nozzles must be cooled. Nozzle heat losses are also included in the calculations. Optimum nozzle geometries are evaluated. Author
- Particle Accelerators