Investigation On The Impact Heat Transfer Characteristics Of Annular Cavity Structure In Casing

The structure of the air passage in the aero-engine turbine casing is very complex,which presents some local characteristics,such as sudden expansion,contraction,obstacle bulge,groove and impinging jet.These local complex structures(especially the impinging jet structure)make the heat transfer in the casing have strong local characteristics,so it is necessary to have an investigation on the heat transfer characteristics of these local structures.In this paper,the annular cavity structure inside the casing is studied by the combination of experiment and numerical simulation.The influence of the relative impact height,the relative circumferential hole spacing,the impact angle,the row number of impact holes,the arrangement of the impact hole,the initial crossflow and the circumferential leakage on the heat transfer characteristics of the impact target are analyzed.The following conclusions are drawn within the range of parameters studied:(1)For all the structures studied in this paper,the heat transfer intensity on the impact target is enhanced with the increase of the impact Reynolds number.(2)When the relative impact height is 3,the heat transfer strength of the stagnation zone on the impact target is the strongest in the 3 structures,and the average heat transfer intensity on the impact target is the strongest when the relative impact height is 9.(3)The less the circumferential hole spacing,the denser the circumferential arrangement of the impact hole,and the average heat transfer intensity on the impact target is stronger.The more the impact hole row number,the denser the axial arrangement of the impact hole,and the average heat transfer intensity on the impact target surface is stronger.(4)The average heat transfer intensity on the impact target surface is stronger when the impact holes are arranged in cross type.(5)The heat transfer intensity on the impact target is enhanced by the addition of the initial crossflow,and the overall heat transfer intensity on the impact target is stronger with the increasing flow ratio under the same impact Reynolds number.The heat transfer intensity on the impact target is weaken by the circumferential leakage.