报告题目：FILM COOLING JET UNDER VARYING BLOWING RATIO

报告人：Dr. Michael D. Atkins（ University of the Witwatersrand）

报告时间：2025年9月2日（周二）下午14:00  

报告地点：明故宫校区A8-701会议室

报告内容简介：

The blowing ratio (M) determines the coverage and extent of attachment/detachment of a film cooling jet over and to a downstream flat endwall (or turbine blade surface). However, insight into their alteration due to the blowing ratio has been largely inconclusive. Therefore, we aim to elucidate its role. To this end, a series of experiments were conducted, in a zero-pressure gradient (PG) channel, where the blowing ratio was varied from M = 0.5 to 2.0 for a fixed film cooling jet Reynolds number of ReD = 14,000, based on the ejection hole diameter D. For visualization and quantification of the film cooling jet structures e.g., kidney vortex cores’ transverse spacing, plume height, and detachment length, particle image velocimetry with planar laser illumination was employed. Our results demonstrate that the dependence of film cooling jet’s detachment on blowing ratio is the following: at M = 1.5 the film cooling jet is detached from the endwall, at M = 1.0 the film cooling jet is semi-attached, and at M = 0.5 the film cooling jet is attached. For the detached regime the film cooling jet height increases monotonically with downstream distance, and for the semi-detached regime the jet cores’ vertical distance from the surface increases until a local maximum at x/D ≈ 2.0 is reached, and then reduces which is indicative to reattachment. For the attached regime, the jet core height is the lowest for the all the blowing ratios tested.

报告人简介：

Michael Atkins is a Senior Lecturer in the School of Mechanical, Industrial and Aeronautical Engineering of the University of the Witwatersrand (Wits), South Africa, and received a PhD (Wits, South Africa), an MSc (with Distinction, Wits, South Africa) and a BEng (with First Class Honors, University of the West of England, Bristol, UK). Dr. Atkins’ research interests are in wind energy harnessing technology and thermal-fluidics in automotive brake discs and gas turbines.