伴随水力空化现象的对流换热数值研究

以水为介质,建立了液体流动的混合物多相流模型及空化模型,运用CFD方法对水平圆管内伴随有水力空化现象的受迫对流换热过程进行了数值研究,详细分析了管道入口压力、入口温度和限流孔与管道直径比等因素对水力空化及对流换热过程的影响规律。数值模拟结果表明,空化现象出现在圆管喉部(限流孔)壁面附近区域;与相同流量下无空化时的传热相比,在发生空化现象的区域,传热壁面被蒸汽所覆盖导致传热急剧恶化,而在远离空化发生区域的下游位置,由于空化的扰流作用使得加热壁面与流体之间的传热得到明显改善。

Investigation on Convective Heat Transfer With Hydrodynamic Cavitation

With water as a cavitation medium,both mixture multiphase flow model and cavitation model were established,and CFD method was used to simulate the forced convection heat transfer with hydrodynamic cavitation in a horizontal circular tube.The effects of such factors as inlet pressure,initial liquid temperature and ratio of orifice to pipe diameter on cavitation and heat transfer were discussed in detail.The results show that cavitation occurs near the wall of pipe throat where heat transfer is weakened because of a lower thermal conductivity of vapor.However,heat transfer is significantly enhanced at the downstream of circular tube due to the disturbance caused by cavitation.