Abstract: In order to improve the aerodynamic performance of high bypass ratio turbofan engines ，reduce their fuel consumption and emissions，and meanwhile take the cost and weight into consideration，an integrated concept is proposed for the intermediate turbine duct(ITD) between high pressure turbine(HPT) and low pressure turbine(LPT). The new struts，mounted in the duct，replace the original struts and the following low pressure inlet guide vanes(IGV). That is to say，the new struts have to provide the downstream rotor blade row with suitable inlet conditions. A sample is designed and flow field analysis is performed through numerical simulation. The results show that the exit Mach number and tangential velocity of the new ITD are in good agreement with the original，which proves that the integrated design is valid. The total pressure loss of the new ITD is 4.3% at design point conditions，which is a little bit higher than the original(4.1%)，but it can adapt to off-design point conditions much more than the original，which reflects that it is superior in some ways.

Key words: High bypass ratio turbofan engine；Intermediate turbine duct；Integrated concept；Struts；Low pressure inlet guide vanes

摘要： 为了提高大涵道比涡扇发动机气动性能，降低其燃油消耗与污染物排放，同时考虑成本与重量因素，针对其高、低压涡轮之间的过渡流道，提出了一体化概念，即新设计的支板代替原型整流支板与低压涡轮第一级导叶，使其也能够为下游转子提供合适的进气条件。对一算例开展了设计工作，并通过数值模拟进行了流场分析，结果表明带一体化支板涡轮过渡流道与原型涡轮过渡流道出口马赫数与切向速度吻合很好，验证了一体化设计的有效性。带一体化支板的过渡流道设计点工况总压损失为4.3%，较原型流道总压损失略有增大(原型流道总压损失4.1%)，但带一体化支板的过渡流道更能适应非设计点工况，具有一定的优越性。

关键词: 大涵道比涡扇发动机；涡轮过渡流道；一体化概念；支板；低压涡轮导叶