Prediction of void fraction of R290 in a horizontal condenser.

In a vapor compression refrigeration and air conditioning system, two-phase flow of refrigerant generally takes place in the condenser and evaporator. Different flow patterns can be found the condenser pipe depending on the position of the pipe relative to the inlet and outlet side. Investigation on the behavior of refrigerant void fraction in a horizontal condenser of a 5.28 kW air conditioner using R290 has been carried out. The void fraction was calculated by using data of refrigerant enthalpy, vapor quality, density, and volume of refrigerant in a pipe segment. In general, refrigerant mass vapor quality of refrigerant is almost identical for different condensing temperature. At the position near the pipe inlet, the void fraction is maximum and drops at a slower rate until it reaches 0.7 of length of the pipe. From this position to the outlet of condenser, the void fraction decreases at a higher rate. The variation of refrigerant density along the condenser pipe causes the lower rate of change of void fraction at the position near the inlet and higher rate of change of void fraction near the condenser outlet. [ABSTRACT FROM AUTHOR]