A Novel Transonic Fan Swept Outlet Guide Vane Using 3D Design Optimization

In our previous work on a transonic fan swept outlet guide vane (OGV) for a small turbofan engine (GT2011-46363), we showed a novel oscillatory casing profile that leads to approximately 20% loss reduction, using a numerical design optimization method. In this paper we analyze the resulting geometry of an optimization based on a blade representation which is able to realize significantly larger surface modifications. The final optimized design displays a novel blade geometry that has its maximum blade thickness at around 80% blade chord (located between the blade’s mid-chord and trailing edge) especially in the mid-span region. The flow physics explaining why this blade geometry without the oscillatory casing profile has the same loss reduction level of more than 20% at the peak efficiency point are discussed, focusing on the secondary flow and span-wise static pressure gradient on the blade suction side.