Pool Boiling Heat Transfer in Saturated R407C Using Reentrant Cavity Surfaces

Abstract

The nucleate pool boiling phenomenon has immense heat transfer applications due to the ability to remove significant quantities of heat from the heating surface with limited temperature differences. Enhancing the pool boiling heat transfer coefficient (HTC) has gained the important consideration in contemporary research for the conservation and efficient utilization of material and energy in the design of boilers. Many types of modification have been tested for enhancing the HTC. One such method is the application of reentrant cavity. An experiment investigation has been carried out to study the nucleate boiling heat transfer from reentrant cavity tubes to a pool of saturated refrigerant R407C at the saturation temperature of 7 °C and 10 °C. An analysis of experimental data shows the reentrant cavities with the mouth size of 0.21, 0.25, 0.31, 0.41, and 0.51 mm can be advantageous for enhancing the HTC of plain tubes. The mouth size of 0.21 mm for boiling R407C has shown maximum enhancement compared to other sizes. A correlation for reentrant cavity surfaces has also been developed and validated with the experimental results.