Flow Characteristics of Helical Capillary Tube for Transcritical CO2 Refrigerant Flow

Helically coiled capillary tubes flow is characterized for transcritical CO2 refrigerant numerically, developing theoretical model established on fundamental equations of mass, energy and momentum considering homogeneous two phase flow. Various friction factors models are compared, present in the open literature. The results obtained from the present model are fairly matches with the simulation results Mori & Nakayama and Schmidt friction factors agree reasonable well with mean average error of 2.2% and 5.7% for R744, respectively. The present model may be used to design helical capillary tubes working with CO2 refrigerant.