Cooling Structures Design And Conjugated Heat Transfer Calculation For High Stage Cascade Of A Gas Turbine

In order to improve efficiency of gas turbine, The turbine inlet temperature is increasing continuously. But with the increasing of gas temperature, the temperature and thermal stress of blade is also increasing, they bring grate damage to blade, so in order to insure the safe of the blade and improve its life-span, using advanced cooling technique to reduce the temperature of blade has became the key points of engine development. This thesis gives the cooling structure of some vane and rotor, then does the conjugated heat transfer calculation.In this thesis, the author designs film cooling and impingement cooling in leading edge of the van, impingement cooling in the center, convection cooling structure with a gap in the tail, wriggling passage with lots of rib in leading edge and center of the rotor, in the trailing edge the author desiges a structure like the Chinese character"jing". With the help of parametric modeling methods, this paper utilizes UG 5.0 to model the cooling structures and make use of ICEM to discrete the computational domain. Finally, conjugated heat transfer calculation is applied for the van and rotor.With temperature field of the van and rotor from CFX Post, pressure distribution and flowing process of cooling air, coefficient of heat transfer and heat flux, this thesis analyse the influence of cooling air to heat transfer and shows the result. Cooling air from the leading edge covers with the blade very vell, reduces the heat exchange capacity between blade and fuel gas, impingementing air reinforces the convection coefficient of internal surface of the blade, enhances the heat exchange capacity between cooling air and internal surface, drops the temperature of the van. Bar shape passage in trailing edge increases the heat transfer area and makes the cooling air move disorderly, reinforces the convection coefficient of internal surface, enhances the heat exchange capacity, achieves good result in cooling. Wriggling passage enhances the utilization of cooling air and the ribs in it makes the cooling air move disorderly, reinforces the convection coefficient of internal surface, enhances the heat exchange capacity, drops the temperature of the leading and center of the rotor. With the structure like the Chinese character"jing", the trailing of rotor also drops its temperature, because the heat transfer area has increased and the air moves more disorderly, with the velocity of air increasing, the convection heat transfer is being enhanced and the cooling influence is more obvious.Finally, the author comes to a conclusion that using the cooling structures in this thesis, the cooling requirement have been met.