Study On Internal Flow And Heat Transfer Characteristics Of Laminate Cooling Structure Of Flame Tube

The laminate structure is widely employed in enhanced cooling of aero-engine hot-section components because of its less gas consumption and higher cooling efficiency.Therefore,it becomes indispensable to explore the application of the laminate cooling on the aero-engine components(such as the laminate cooling structure of the flame tube wall).Based on the above background,this paper uses numerical simulation and experimental methods to explore the flow and heat transfer characteristics of the cooling structure of the flame tube wall.The flow and heat transfer characteristics of the structure of the flame tube wall are studied by using numerical calculation.The effects of parameters such as impingement opening rate,the diameter of the pin-fins and overflow hole,impact height,flow direction spacing,span spacing and jet Reynolds number on the flow and heat transfer characteristics of the laminate cooling structure are analyzed.The calculation results show: The impingement opening rate increases the total pressure drop and the equivalent flow coefficient increase of the laminate,the drag coefficient increases and the heat transfer capacity decreases.The diameter of the pin-fins has little effect on the total pressure drop and the equivalent flow coefficient.Increasing the diameter of the pin-fins can reduce the drag coefficient of the laminate.When the dr=0.6mm,the K value is the largest.The diameter of the overflow hole increases the total pressure drop and the drag coefficient of the laminate,and the opposite is that the equivalent flow coefficient increases and the corresponding heat transfer capacity increased.The impact height increases,the total pressure drop,and the drag coefficient decrease,the equivalent flow coefficient increases slightly,and the impact of the impingement height on the thermal capacity is not monotonous.The increase of flow spacing and span spacing will increase the heat transfer capacity of the laminate structure,the pressure drop of the laminate structure will increase,the flow coefficient will be almost constant,and the drag coefficient will not exhibit a monotonous linear relationship with the change of the flow and span space.The increase of jet Reynolds number also leads to an increase in pressure drop,which has little effect on the equivalent flow coefficient,but the drag coefficient decreases,and the heat transfer capacity of the laminate cooling structure increases,and it almost changes linearly with the increase of the jet Reynolds number.In order to verify the accuracy of numerical calculations,this paper carries out experimental verification of typical working conditions.Based on the numerical simulation,the influence of the diameter of the impingement hole,the diameter of the pin-fins and the diameter of the overflow hole on the internal flow and heat transfer characteristics of the laminate are studied by experimental methods.The experimental results show that the average Nusselt number of the laminate increases with the increase of the diameter of the impingement hole and the pin-fins,but it hardly changes with the increase of the diameter of the overflow hole.The total pressure loss coefficient shows a monotonously decreasing trend with the increase of the diameter of the impingement hole and the overflow hole but remains almost unchanged with the increase of the diameter of the pin-fins.Overall,the maximum error between experiment and calculation,the average Nusselt number is within 20%,and the total pressure loss coefficient is within 27.4%.