毛细管内R410A两相流动阻力特性实验研究

Experimental investigation on the R410A two phase pressure drop in capillary tubes

毛细管广泛应用于分体式空调、多联式空调(热泵)机组的室内和室外换热器的分流流量调节,准确预测毛细管内两相流制冷剂的压降特性是快速实现换热器分流毛细管匹配的关键。提出了基于近似积分实现变密度条件下毛细管内两相流摩擦阻力因子的计算方法,并通过实验方法研究毛细管内径对R410A制冷剂在毛细管内的两相流摩擦阻力因子的变化规律。结果表明:毛细管中的两相流摩擦阻力因子随制冷剂Re数的增大而减小,这与经典的Churchill模型预测的趋势一致,但其数值比Churchill模型增大1倍以上,且随着毛细管内径的减小,其管内两相流动摩擦阻力因子f也越小。

Capillaries are widely used in the shunt flow regulation of indoor and outdoor heat exchangers of split air conditioners and multi-split air conditioning(heat pump)units.Accurate prediction of the pressure drop characteristics of two-phase flow refrigerants in capillary tubes is the key to quickly realize shunt capillary matching of heat exchangers.Propose a method for calculating the friction resistance factor of two-phase flow in capillary tube under the condition of variable density based on approximate integral is proposed,and the effect of capillary diameter on the friction resistance factor of R410 a refrigerant in capillary tube is studied experimentally.The results show that the friction resistance factor of the two-phase flow in the capillary tube decreases with the increase of the refrigerant Re number,which is consistent with the trend predicted by the classical Churchill model,but its value is more than twice that of the Churchill model,and the friction resistance factor f of the two-phase flow in the capillary tube decreases with the decrease of the inner diameter of the capillary tube.