2022 Volume 50 Issue 6 Pages 335-347
Multi-blade Fan is simple structure and can give high pressure rise in small rotating speed. However, the fan has complicated flow field due to many numbers of forward blade. Many researchers have studied on noise prediction and development of low noise fan. However, generation of the hexa grids that have been used in many previous studies is difficult for unskilled operators. The tetra grids are easier to generate than hexa grids. We therefore investigated influence of tetra grid resolution on fan performance and aerodynamic noise. We confirmed error within 1% of calculated total pressure rise and error within 5.0 dB of calculated noise spectrum by using 560 million tetra grids. We then confirmed that it is important to secure the grid resolution which could represent complicated vortex structure on blade surface and wall near tongue for getting reasonable errors of the total pressure rise and the noise spectrum.
