Experimental and numerical investigation of slot dimple tube on the heat exchanger performance

The present work investigated experimental and numerical the effect of internal radiate on the external tube on heat transfer coefficient and pressure drop in tube for range of Reynolds Number of (4000-16000). The study also discuss the different in results between the slot dimple tube and plain tube. Heat transfer and pressure drop for test tube were evaluated and presented as dimensionless value by Nusselt number and friction factor. Overall enhancement ratio of dimpled tube is discussed. Thermal and hydrodynamic results of CFD study are presented in form velocity vector and contour of local heat transfer coefficient. The results comparison of Nusselt number between plain tube and present slot dimples tube, shows that slot dimples tube enhance the heat transfer between 1.584 - 2 times the plain tube, and When compare between experimental and correlated Nusselt number for present slot dimple tube, the result show deviation in the test range of Reynolds number. The numerical results were in good agreement with the present experimental results. The deviation is within 6 - 22% higher for numerical at low and high Reynolds number, respectively. The overall enhancement ratio for present slot dimpled tube dependent on plain tube, the result depict that the slot dimple tube gave high enhancement in heat transfer relative to plain tube. The enhancement ratio is varied from (1.09 to 1.15) for range of Reynolds numbers between (4000 to16000).