HEAT TRANSFER AND PRESSURE DROP IN TAPE GENERATED SWIRL FLOW.
MASSACHUSETTS INST OF TECH CAMBRIDGE NATIONAL MAGNET LAB
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Improvements in heat transfer for equal flow rates of up to 85 were observed for the non-boiling swirl flows with heating, but the improvement with cooling was substantially less. Compared on the basis of equal pumping power, improvements in heat transfer of up to 35 were observed for the tighter tape twists. A method for predicting the heat transfer coefficient for non-boiling swirl flows was developed. The surface boiling characteristics of swirl flow were found to be similar to those observed in straight flow. The boiling curves for various velocities were asymptotic to a fully developed line at high wall superheats, and the visually observed point of incipient boiling and the transition to the fully developed boiling asymptote were predictable by conventional straight flow methods. It was concluded, therefore, that the dominant surface boiling heat transfer mechanism was similar for both swirl and straight flow. For non-boiling swirl flows, the decrease in the pressure drop with heating was slightly less than is usual with straight flows, while the increase in the pressure drop with surface boiling was substantially less. A method for predicting the difference in each case is presented. Author
- Air Conditioning, Heating, Lighting and Ventilating
- Fluid Mechanics