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ISSN Online: 2379-1748
ISBN Flash Drive: 978-1-56700-469-4
ISBN Online: 978-1-56700-470-0
Second Thermal and Fluids Engineering Conference
EFFECTS OF GROOVE ARRANGEMENTS ON THE FLOW PATTERN AND HEAT TRANSFER IN A HEAT EXCHANGER TUBE WITH DISCRETE GROOVES
Abstract
In this work, a numerical investigation on the effects of groove arrangements on the flow pattern and heat transfer in an internally grooved heat exchanger tube was presented. Three groove arrangements, including P-type, V-type and W-type were selected to perform the study. Visualization of the flow structures in the grooved tube shows that a single longitudinal swirl flow is generated in the P-type grooved tube; multiple longitudinal swirl flows are induced in the V-type grooved tube, while no longitudinal swirl flow is generated in the W-type grooved tube, indicating that groove arrangements have significant effects upon the flow patterns in the grooved tube. Comparison of the heat transfer performance in the grooved tubes with different arrangements shows that the average Nusselt number in the V-type grooved tube is about 19.5%–34.2% and 42.6%–43.7% higher than those in the P-type grooved tube and W-type grooved tube, respectively, implying that the V-type grooved tube is more effective for heat transfer. To further understand the effects of groove arrangements on the heat transfer in the grooved tubes, and reveal the essence of heat transfer enhancement, an analysis has also been carried out from the point view of entransy dissipation extremum principle. The results demonstrate that multiple longitudinal swirl flows can reduce the equivalent temperature difference of the heat exchanging process, and thereby enhance the heat transfer efficiency in the grooved tube, compared to the other two flow patterns.