Modeling for multi-pass parallel flow condenser with the effect of refrigerant mal-distribution

Abstract

Performance of multi-pass parallel flow condenser (MPFC) is unavoidably influenced by the refrigerant-side flow mal-distribution (MD) caused by the pressure drop in headers. Thus, a numerical MD model is proposed to predict flow distribution and performance parameters of MPFC with vertical headers and horizontal tubes. The advantage of MD model over UD model (uniform distribution model, refrigerant is assumed to be distributed into each tube evenly by ignoring the effect of header pressure drop) has been indicated by achieving better agreement with experimental data measured from variably-sized condensers A–D and data derived from a published literature. The effects of condenser aspect ratio, pass arrangement (pass number and tube number of each pass) and refrigerant mass flow rate on flow distribution, heat transfer and refrigerant-side pressure drop are investigated. The prediction results indicate that heat capacity varies much less than flow distribution and pressure drop with the change of aspect ratio or pass arrangement. Moreover, for a fixed geometry, a moderate flow rate can be searched by the MD model to obtain well flow distribution, high capacity and efficiency.