507 冷風加工における超音速先細末広ノズルの開発とその冷却性(切削・研削・研磨加工II)

概要

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Cooling air- turning needs to develop a supersonic nozzle that is capable of supplying high speed air at turning point. In this study, supersonic Convergent-Divergent nozzle (C-D nozzle), which can make stagnation-cold-air up to the sound speed in the convergent section and expand the cold air to achieve the sound speed in the divergent section, are designed on an assumption of thermal equilibrium under isentropic expansion. Experimental evaluation of the supersonic air clarifies that the C-D nozzle goes over 13mm(max. 37mm). As for cooling ability of the cold air in the potential core, average heat transfer coefficients of the cold air are 1,000-1,400W/(m^2K) depending on both pressure of chamber P_0 and impinging air P. The optimum air supply condition of each nozzle is verified experimentally and expressed using non-dimensional parameters, Reynolds number Re and Nusselt number Nu.
一般社団法人日本機械学会の論文
2011-10-22