关键词: 正交试验, 冷却, 横向射流角, 冷却效率, 换热系数

Abstract:

An investigation on the cooling characteristics of multiple rows of opposite lateral ejection angle film cooling is conducted by means of an orthogonal numerical simulation test. The numerical simulation is conducted by a Realizable k-ε turbulent model and a two-layer velocity zonal model using commercial numerical calculation software. The purpose of the investigation is to reveal the influence of such parameters as lateral ejection angle β, orifice coefficient F, length to width ratio S/P and blowing ratio M, on film cooling. Besides, this paper also tries to find how the above parameters act on cooling respectively. The results show that, compared with the classical counter-rotating vortex pair which appears in the flow field of double-jet film cooling, the vortex pair structure in the downstream of the film-outlet of multiple-rows of opposite lateral ejection angle film cooling is asymmetrical, and cooling is maintained by ejecting cooling jets through rows of holes continuously. It is worth noting that this structure of film cooling achieves excellent cooling effect. The orifice coefficient is found to have the greatest impact on average film cooling effectiveness. Descending order of other parameters, based on their impacts on the average film cooling effectiveness, is: blowing ratio, length to width ratio, and lateral ejection angle, while descending order of the parameters, based on their influence on the heat transfer, is: β=55, M=1.2, F=2%, S/P=1.4.

Key words: orthogonal test, cooling, lateral ejection angle, film cooling effectiveness, heat transfer coefficient