With the improvement of requirement,design and manufacture technology,aero-engines for the future are characterized by further reduction in fuel consumption,cost,but increment in propulsion efficiency,which leads to u...With the improvement of requirement,design and manufacture technology,aero-engines for the future are characterized by further reduction in fuel consumption,cost,but increment in propulsion efficiency,which leads to ultra-high bypass ratio.The intermediate turbine duct(ITD),which connects the high pressure turbine(HPT) with the low pressure turbine(LPT),has a critical impact on the overall performances of such future engines.Therefore,it becomes more and more urgent to master the design technique of aggressive,even super-aggressive ITDs.Over the last years,a lot of research works about the flow mechanism in the diffuser ducts were carried out.Many achievements were reported,but further investigation should be performed.With the aid of numerical method,this paper focuses on the change of performance and flow field of ITD,as well as nearby turbines,brought by rising angle(RA).Eight ITDs with the same area ratio and length,but different RAs ranges from 8 degrees to 45 degrees,are compared.According to the investigation,flow field,especially outlet Ma of swirl blade is influenced by RA under potential effect,which is advisable for designers to modify HPT rotor blades after changing ITD.In addition to that,low velocity area moves towards upstream until the first bend as RA increases,while pressure loss distribution at S2 stream surface shows that hub boundary layer is more sensitive to RA,and casing layer keeps almost constant.On the other hand,the overall total pressure loss could keep nearly equivalent among different RA cases,which implies the importance of optimization.展开更多
基金support from the National Natural Science Foundation of China(No.51406204)
文摘With the improvement of requirement,design and manufacture technology,aero-engines for the future are characterized by further reduction in fuel consumption,cost,but increment in propulsion efficiency,which leads to ultra-high bypass ratio.The intermediate turbine duct(ITD),which connects the high pressure turbine(HPT) with the low pressure turbine(LPT),has a critical impact on the overall performances of such future engines.Therefore,it becomes more and more urgent to master the design technique of aggressive,even super-aggressive ITDs.Over the last years,a lot of research works about the flow mechanism in the diffuser ducts were carried out.Many achievements were reported,but further investigation should be performed.With the aid of numerical method,this paper focuses on the change of performance and flow field of ITD,as well as nearby turbines,brought by rising angle(RA).Eight ITDs with the same area ratio and length,but different RAs ranges from 8 degrees to 45 degrees,are compared.According to the investigation,flow field,especially outlet Ma of swirl blade is influenced by RA under potential effect,which is advisable for designers to modify HPT rotor blades after changing ITD.In addition to that,low velocity area moves towards upstream until the first bend as RA increases,while pressure loss distribution at S2 stream surface shows that hub boundary layer is more sensitive to RA,and casing layer keeps almost constant.On the other hand,the overall total pressure loss could keep nearly equivalent among different RA cases,which implies the importance of optimization.
