Application of a three-dimensional viscous transonic inverse method to NASA rotor 67

Abstract: The development and application of a three-dimensional inverse methodology in which the blade geometry is computed on the basis of the speci cation of static pressure loading distribution is presented. The methodology is based on the intensive use of computational uid dynamics (CFD) to account for three-dimensional subsonic and transonic viscous ows. In the design computation, the necessary blade changes are determined directly by the discrepancies between the target and initial values, and the calculation converges to give the nal blade geometry and the corresponding steady state ow solution. The application of the method is explored using a transonic test case, NASA rotor 67. Based on observations, it is conclusive that the shock formation and its intensity in such a high-speed turbomachinery ow are well de ned on the loading distributions. Pressure loading is therefore as effective a design parameter as conventional inverse design quantities such as static pressure. Hence, from an understandingof the dynamics of the ow in the fan in relation to its pressure loading distributions, simple guidelines can be developed for the inverse method in order to weaken the shock formation. A qualitative improvement in performance is achieved in the redesigned fan. The nal ow eld result is con rmed by a well-established commercial CFD package