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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

NUMERICAL ANALYSIS OF THERMAL PERFORMANCE OF A SWIRL COOLING TUBE WITH DIMPLES AT THE WALL

Get access (open in a dialog) DOI: 10.1615/IHTC16.ctm.022829
pages 3699-3705

Abstract

In a swirl cooling system pertinent to modern gas turbine leading edge, there is still great potential for the improvement of heat transfer and pressure loss performance. Dimple is a so called vortex generator and the swirl cooling performance can be optimized by arranging dimples at the swirl tube inner wall. In this paper, a numerical study is conducted to investigate the swirl cooling performance with five tangential inlet jets. Comparisons between swirl cooling systems with a smooth tube and a dimpled tube with dimple depth to projection diameter of 0.3 have been carried out. Reynolds numbers are based on the tube diameter, which ranges from 10,000 to 40,000. Polyhedral meshes and Shear-Stress Transport (SST) k−ω model are adopted for the computations. The results shows that the dimpled tube can slightly reduce the wetted-area averaged Nusselt numbers but increase the total heat transfer by up to 7.2 % due to the heat transfer area enhancement. Moreover, it is interesting to find that dimples can remarkably reduce pressure loss in the swirl cooling system by up to 17.6 % compared with that of smooth tube. The flow field information is further excavated and it is believed that dimples at the wall can suppress circumferential velocity and swirling intensity in the swirl tube, which explains the pressure loss mechanisms.