轴流式翼型桨的流动分析

Flow Characteristics of Axial Flow Impellers for Viscous Fluids in Stirred Tanks

采用激光多普勤测速仪，对水、甘油和羧甲基纤维素（ＣＭＣ）三种介质中带有轴流式翼型桨的搅拌釜内的流场进行测定。并就流型转变、剪切速率、表观粘度分布和泵送能力进行了详细的研究和分析。结果表明，搅拌釜内流型仅随雷诺数和桨叶结构变化；剪切速率及表观粘度在全釜分布相当不均匀，在研究范围内，剪切速率相差５０倍，表观粘度为４．５倍；对粘稠物系，翼型桨泵送能力有所下降，并随雷诺数的减小而减小。

A laser Doppler anemometer was used to study the flow patterns,share rates,apparent viscosities and pump capacities for axial flow impellers in water,88% and 98% glycerine and a 1.5 wt%aqueous solution of sodium-carboxymethyl cellulose(CMC) in a stirred vessel.Results showed that flow patterns varied with Reynolds numbet and construction of impellers.The shear rates and apparent viscosities around impellers were quite different from those in the circulation regions.The pump capacity coefficients decreased with low Reynolds numbers for viscous fluids.