STUDIES ON PROPERTIES OF FLOW CAVITATION NUMBER AND MINIMUM PRESSURE COEFFICIENT IN SHORT CLOSED CONDUITS  

作　　者：Ding Zhuo-yiYangtze River Scientific Research Institute, Wuhan 430010, P. R. China 

出　　处：《Journal of Hydrodynamics》1994年第3期1-6,共6页水动力学研究与进展B辑（英文版）

摘　　要：For a short closed conduit with smooth (streamline pattern) boundary, the comparison of minimum pressure coefficient at boundary, - Cpm , which obtained from model tests, with flow cavitation number a is possible to describe the property of preventing cavitation in the closed conduit.In this paper, analytical results show that the ratio σ/ - Cpm decreases with increasing Reynolds number Re, when the configuration of the conduit is designed, and this ratio approaches a constant when Re = 106 or so. The model test data for five engineering cases of the short closed conduit with various configuration indicates that the analytical results are reliable. Therefore, the value of the ratio σ/ - Cpm corresponding to that of Reynolds number in model (Re)m ≥106 must be taken so as to correctly describe the cavitation property of the studied conduit. The condition of Lr ≥ 10-4[(Re)p]2/3 should be satisfied ( Lr is model length scale; (Re)p is Reynolds number in prototype) when the model is designed by Froude criterion of similarity.For a short closed conduit with smooth (streamline pattern) boundary, the comparison of minimum pressure coefficient at boundary, - Cpm , which obtained from model tests, with flow cavitation number a is possible to describe the property of preventing cavitation in the closed conduit.In this paper, analytical results show that the ratio σ/ - Cpm decreases with increasing Reynolds number Re, when the configuration of the conduit is designed, and this ratio approaches a constant when Re = 106 or so. The model test data for five engineering cases of the short closed conduit with various configuration indicates that the analytical results are reliable. Therefore, the value of the ratio σ/ - Cpm corresponding to that of Reynolds number in model (Re)m ≥106 must be taken so as to correctly describe the cavitation property of the studied conduit. The condition of Lr ≥ 10-4[(Re)p]2/3 should be satisfied ( Lr is model length scale; (Re)p is Reynolds number in prototype) when the model is designed by Froude criterion of similarity.

关 键 词：cavitation number minimum pressure coefficient conduit. 

分 类 号：O354[理学—流体力学]