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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Heat Transfer Measurements in a Swirl Chamber Using the Transient Liquid Crystal Technique

Get access (open in a dialog) DOI: 10.1615/IHTC15.hte.009231
pages 4279-4289

要約

Swirling flow in tubes is a promising method for heat transfer enhancement compare to an axial flow in a smooth tube. One potential use is the cooling of a turbine blade leading edge especially due to high thermal loads. However, the flow and the heat transfer in such a swirl chamber are far from being completely understood. To gain understanding of the cooling capability, the heat transfer coefficients were experimentally studied by using thermochromic liquid crystals. For the evaluation of the heat transfer coefficients and an accurate cooling design it is essential to gain the local fluid temperature, which is usually unknown in technical applications. In vortex or swirl tubes the occurring Ranque-Hilsch effect, which causes a radial energy separation in the tube, complicates the determination of the fluid temperature. For this reason we presented a method to process the local adiabatic wall temperature as a correct reference temperature. Therefore, the radial temperature ratio within the steady state flow is recorded to determine the adiabatic wall temperature from the center temperature during the transient experiment.We showed pressure loss and heat transfer results for various Reynolds and swirl numbers. The averaged Nusselt numbers are more than four times higher than the one in a smooth tube. The circumferential velocity with strong gradients in the wall region is the major mechanism for the high heat transfer in the swirl tube.