AN EXPERIMENTAL STUDY OF SOME BASE INJECTION TECHNIQUES AND THE EFFECT OF LARGE PRESSURE GRADIENTS ON TURBULENT DIFFUSION PROCESSES.
NEW YORK UNIV N Y
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Results of an experimental study of some base injection techniques and the effect of large pressure gradients on turbulent diffusion processes in an axisymmetric flow past a slender body at Mach number 3.92 and Reynolds number 3.85 x 10 to the 7th power ft. are presented. Base injection techniques were studied using gaseous hydrogen, helium, nitrogen, and argon as injectants. In each case, it is noticed that the base pressure reaches its peak value much faster i.e., for a smaller injection rate with a low molecular weight gas and that a larger increase in base pressure is accomplished with the lighter gas. Some schemes show very irregular behavior in the variation of base pressure with injection. In the study of diffusion processes it is found that the mass diffusion process is not affected at all by the pressure gradients produced in the flow field and that mass, momentum, and thermal diffusion are not the same. This leads to the conclusion that assumptions of Lewis number, Prandtl number, and Schmidt number equal to unity are not correct, especially for problems with large pressure gradients. Author
- Fluid Mechanics