Study on Heat Transfer and Pressure Drop in a Spiral Capillary Tube

Abstract

Recently, it is important to improve the performance of the air-conditioners and refrigerators for domestic use. Many studies on heat transfer tubes are carried out from the above perspective. It is expected that using the spiral capillary tubes might enhance the heat transfer characteristics in comparison with those of smooth straight tubes by the effect which is caused by secondary flow. In this study, to clarify the heat transfer and pressure drop characteristics in a spiral capillary tube, experiments on the effect of helix angle are carried out in the case of water as a working fluid, helix angles are 0, 10, 20, 30, 60 and 75.5 degrees, and in the case of R134a, helix angles are 0, 10 and 30 degrees, and the correlations for pressure drop on account of helix angle. As the results of the experiment, heat transfer and pressure drop increase with increase of helix angle in the case of single phase flow. However, in the case of two phase flow, it is not so effective.