Abstract:

Refrigerant maldistribution is an important factor to influence pressure drop characteristic of microchannel evaporator, so a new pressure drop model of microchannel evaporator is proposed for accurately predicting the pressure drop influenced by refrigerant maldistribution. This model considers all the local and frictional pressure losses from the inlet to outlet of microchannel evaporator, imports simplified quality distribution function to calculate the inlet state of each microchannel tube, and presents a flow path pressure drop balance algorithm to iterate microchannel evaporator pressure drop. This model can be applied to the condition that evaporator inlet is two-phase condition (inlet quality is less than 0.45) and refrigerant mass flux inside inlet header is less than 764 kg/m²s. It is shown that the model results can meet the real condition of flow rate and temperature distribution trend of refrigerant inside microchannel evaporator, and the deviation with evaporator pressure drop test data is less than 8%.

Key words: pressure drop, simulation model, two phase distribution, microchannel evaporator