Paper 28: The Accuracy of the Actuator Disc Method in the Design of Axial Flow Fans

The accuracy of the actuator disc theory as a simple design tool for low-speed axial turbomachines of a few rows is assessed by comparison with a Wu solution of the design (or inverse) problem for a single row. A slight modification to one form of the theory is recommended to improve the overall accuracy, particularly for forced vortex designs near the hub. Compressibility effects have not been considered but the paper presents a simple addition to the theory (based partly on the work of Lewis and Horlock) which allows for the presence of blade thickness on the axial velocity distribution in a typical design calculation.