Heat, Mass, and Momentum Transfer Inside Frosted Tubes—Experiment and Theory

The paper presents a combined experimental and theoretical study on the heat, mass, and momentum transfer in a frosted heat exchanger tube. Experimental evidence suggests that the behavior of the frosted tube is largely determined by the surface roughness of the frost layer. Based on simple stability considerations and the well-known rough pipe results of Nikuradse and von Karman, a theory is presented which predicts the frost surface roughness as functions of RePrkkf and the frost thickness. The theoretical results are shown to be in qualitative agreement with observed results. Heat-transfer and pressure drop calculations based on the predicted roughness are also found to be in fair agreement with observed results.