The concepts required to perform a realistic flow analysis for axial fans are presented and developed, and aerodynamic performance is related to the geometric features of a fan. Algorithms for calculation of flow rate, pressure rise, viscous losses, leakage, and stall are discussed, and an overall framework for estimating performance, efficiency, and noise is developed for layout of a detailed fan and for direct fan performance analysis. Small computer implementation of these procedures into two programs for fan design and performance prediction is presented. Examples of design calculations for several fans are given, and predictions of performance of several existing fans are compared to measured performance. Results show that the relatively complicated algorithms can be readily implemented on small computers and that the results will be reasonably accurate with acceptably short run times.

Units: Dual