| Rotary film cooling is one of the many newly developed film cooling structures,which has a simple method of achieving high cooling by forming a single-sided predominant kidney-shaped vortex by a film hole tangential to the wall effectiveness.In this paper,as the research background,numerical and experimental studies on the flow and heat transfer characteristics of the rotating film cooling are carried out.The research mainly includes three aspects:1.Aiming at the single-row rotating tangential intake air cooling structure,the heat transfer characteristics of the flow were analyzed and discussed,and the physical mechanism of the cooling efficiency was revealed.The influence of the parameters of the gas film pore structure and the fluid flow parameters on the cooling characteristics was systematically studied.2.The influencing factors on the cooling efficiency of the doublerow rotating film were analyzed,and the effects of cooling structure and flow parameters on the cooling characteristics of the double-film rotating tangential inlet were studied.3.The rotating gas film is used to cool the wall of the propeller to simulate the real working conditions.The influence of the flow parameters and structural parameters on the cooling characteristics and the combustion characteristics of the propellant is studied.The rotating tangential inlet which can balance the cooling characteristics and the combustion characteristics of the engine Optimized structure of film cooling.There are some main conclusion: Firstly,the flow field structure and cooling characteristics of single-row rotating tangential inlet gas film cooling holes were analyzed.It is found that the formation of single-vortex vortex is due to the influence of the cooling hole jet on the kidney-shaped vortex pairs.Due to the tangential intake air and the cold air Pushed to the side of the centerline of the gas film hole,one of the eddy was suppressed and the other formed a single-sided kidney-shaped eddy.Changing the structural parameters and the flow parameters can affect the jets generated by the jet,thereby changing the distance between the center of the kidney-shaped vortex and the wall and the rotation speed of the fluid around the core.Increasing the distance between the kidney-shaped vortex core and the wall and increasing the rotation speed of the fluid around the vortex contribute to enhance the lateral coverage of the cooling air and improve the lateral cooling efficiency,but the degree of entrainment in the downstream mainstream is aggravated and the cooling effect is reduced.Further research shows that the increase of blowing ratio and the increase of temperature ratio can increase the distance between the center of a single kidney-shaped swirling vortex and the wall or increase the rotating speed of the fluid around the vortex.Secondly,the cooling characteristics of the double-row rotating film were analyzed.It was found that the tangential inlet of the two rows of front and rear rows formed the superimposed kidney-shaped vortex pairs at the downstream.Under the same amount of coolant per unit area,Row of holes can get higher cooling efficiency.By simulating the actual operating conditions of the burner,it was found that the first row of cooling air flow near the head of the burner hindered the contact of the hot gas with the wall.The second row and the third row of cooling air mainly formed the mixing vortex with the mainstream gas.Part of the flow along the wall,the arrangement of the film holes and the flow distribution of the coolant affect the formation of swirling vortex inside the combustion chamber,affecting the cooling characteristics of the gas chamber and thus the flow field structure and performance of the combustion chamber as a whole. |
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