3482 -- Heat Transfer Augmentation by Coiled Wire Turbulence Promoters in a Horizontal Refrigerant-22 Evaporator PDF

Reports the results of an investigation to study the effect of coiled wires on heat transfer rates inside a horizontal Refrigerant-22 evaporator. A round, stainless steel tube was used as a test section and it was heated electrically. Coiled wires were made of stainless steel, and they were inserted into the tube to create flow disturbances. Data were collected for a six-fold variation in the heat flux and a four-fold variation in the pitch of the coil at a constant mass flow rate of refrigerant. Results indicate a considerable increase in the heat transfer coefficients by the use of these turbulators. The ratio of augmented to plain flow heat transfer coefficients was found to be in the range of 1.05 to 3.3. This was accompanied by a large increase in pressure drops on the order of 300% to 1200%.

KEYWORDS: heat flow, turbulence promoters, horizontal, evaporators, R22, refrigerants, heat transfer coefficient, pressure drop, testing