Research On Characteristics Of Flow And Heat Transfer Of Combustor With Shaped Film Hole

With the increasing performance of modern aero-engine,high turbocharging ratio,high turbine inlet temperature,high thrust-weight ratio,high efficiency and low pollution are the inevitable trends in the future.At the same time,higher requirements are put forward for the cooling of combustion chamber flame tube wall.The shaped film hole is an efficient film cooling structure developed on the basis of cylindrical hole,which provides a new way for cooling technology of flame tube.In this paper,the shaped film hole cooling structure of flame tube is investigated on the flow and heat transfer characteristics Based on the Fluent software,three types of shaped film hole structures are designed,including forward inclined hole,fan-shaped hole and dustpan hole.The main geometric parameters of each film hole structure(forward inclined expansion angle of forward inclined hole,spanwise expansion angle of fan-shaped hole and expansion ratio,inclination angle,forward inclined expansion angle and spanwise expansion angle of dustpan hole)are studied on the influence of the flow and heat transfer characteristics of the flame tube.The following two aspects of research have been carried out.(1).In the same boundary conditions,analyze the temperature distribution on the typical periodic surface,the temperature distribution on the hot side wall,the velocity and vector distribution in the film hole,the pressure and streamline distribution in the film hole and near the outlet and the average cooling efficiency distribution.The effects of different geometric parameters on the flow and heat transfer characteristics are further compared,and the relationship of cooling efficiency relevant to different geometric parameters is summarized.The results show that for the forward inclined hole,the greater is the forward inclined expansion angle,the higher is the cooling efficiency;for the fan-shaped hole,the bigger of the spanwise expansion angle is,the higher of the cooling efficiency is;for the dustpan hole,compared with the non-expanded cylindrical hole,the efficiency of the expandable dustpan hole is obviously improved,while the difference between the semi-expanded hole and the fully expanded hole is rather small,and the smaller of the hole inclination angle is,the higher of the cooling efficiency is.In addition,the forward expansion angle and the spanwise expansion angle has little effect on the cooling efficiency in the scope of this paper.(2)Based on the numerical simulation results,the cooling efficiency formulas are summarized and the main geometric parameters are analyzed.The one-dimensional flow and heat transfer program of the shaped film hole cooling structure of the flame tube is developed,which provides a tool for predicting the distribution of heat transfer characteristics on both sides of the flame tube.