Investigation of performance improvements including application of inlet guide vanes to a cross-flow fan

Abstract

The inherent characteristics of a cross-flow fan allowing for easy thrust vectoring as well as potential airfoil boundary layer control make it an attractive propulsive means for a theoretical vertical takeoff and landing aircraft. However, to compete with current methods of aircraft propulsion, further performance improvements of the cross-flow fan are needed. A baseline model of a cross-flow fan geometry developed by Vought Systems in the 1970s was scaled from a 12- inch diameter rotor to a 6-inch diameter rotor as a more realistic size for integration into a fan-in-wing concept to provide both thrust vectoring and boundary layer control over the wing. Using the computational fluid dynamics software ANSYS CFX, baseline performance trends were verified against previous 12- and 6-inch diameter models. Data from this model was then used to design a configuration of inlet guide vanes in an effort to increase the loading on the first stage of the fan and gain an improvement in pressure ratio over the baseline cross-flow fan. The CFD results were then compared with experimental results from a cross-flow fan test assembly modified to replicate the CFD model with inlet guide vanes. While the application of the particular inlet guide vane configuration did not result in the desired performance improvements, it did validate that computational fluid dynamics can adequately predict the impact of various design changes on the performance of the cross-flow fan as well as provide valuable insight into the behavior of the cross-flow fan for future efforts in performance improvement.