Research On The Flow And Heat Trasnfer Of Combustor-turbine Interactionin Advanced Gas Turbine

The advanced gas turbine power unit is the core equipment of the future clean andefficient energy power systems. With the continuous technical improvement of gasturbine performance and increasingly strict emmission restrictions, the high temperaturecomponents of gas turbine including the combustor and turbine are facing more severechallenges. As the combustor-turbine structure becomes more compact, the flow andheat transfer phenomenon become more complicated. In terms of that, the combustionand turbine interaction effects become more and more prominent. The main interactionfactors include: turbulence intensity, hot streak, wake, radiationand swirl. Especially,the radiation and swirl factors are considered as the primary interaction effects. In thispaper, the interaction effects of combustor and turbine are investigated, mainly focusingon the impact of the thermal radiation and swirling flow on the full-coverage coolingvane system.In this paper, the convection/conduction/radiation conjugate heat transfermechanism is explored by experimental research on the high temperature flat plate filmcooling conjugate heat transfer test rig. Based on the numerical method verified by thefundamental test data, the first stage vane model with internal cooling is taken forsimulations to investigate the convection/conduction/radiation conjugate heat transfercharacteristics under multiple radiative parameter influence. According to the results, itis shown that the radiation causes20-40K temperature rise on the vane surface, and thetemperature distribution varies with different radiative parameter.The mainstream inletradiation affectstemperature distribution of the vane leading edge and pressure sideobviously. The gas composition shows different radiation absorption andemissioncharacteristic under different conditions, which usually complicates the localheat transfer. As the vane metal emissivity is increased, the vane surface temperaturerises slightly.The outlet radiation has little effect on the vane surface except the suctionside near the trailing edge.To investigate the radiative heat transfer in the full-coveragefilm cooling vane system, conjugate heat transfer computationsare conducted, whichprove that the radiation causes50K temperature rise locally on the vane surface. To investigate the interaction effect of the combustor swirling flow field and thevane cooling system, test rigs for fundamental research are established, including thesingle-swirl/model leading edge with film coolingtest rig and multiple-swirls/vane withfull-coverage vane test rig. The swirling flow field and film cooling effectiveness aremeasured respectively.Accordingly, several numerical computations are conducted toinvestigate the flow characteristics of single swirl and multiple-swirls interactionmechanism.Based on the computations of three typical multiple-swirlsarrangements, themultiple-swirls interaction mechanism and flow structure are analyzed. Experimentalresults indicate that for the co-swirl and counter-swirl arrangements, the yaw anglekeeps more than20degrees at the transition piece outlet,which could have substantialimpact on the first stage vane. Based on the numerical computations and experimentalmethod, the interaction mechanism of combustor swirl and vane cooling system isinvestigated. Results show that the cooling system performance is significantly changedunder the swirling field condition.The most influenced area is the vane leading edgeands uction side surface, with some local area not covered by coolant. It is dangeroussituation for the vane under real engine condition.Therefore, it is important to considerthe swirl factor when designing the cooling system of first stage vane.