Experimental and numerical analysis of eight different volutes with the same impeller in a squirrel-cage fan

This article presents the experimental and numerical investigation on the effect of volute spread angle on efficiency, performance and flow pattern inside volute of squirrel cage fan. The flow in a volute is highly complex. It is strongly believed that an understanding of the detailed flow structure in a volute will provide insights into minimizing the losses by isolating the mechanism that contribute to entropy generation. For the study presented here, eight volutes just differing in volute profile equation are studied experimentally and numerically. In all cases volute dimensions were constrained in a specific domain. Attention was focused on the effect of different volutes with the same impeller on fans performance. The overall performances of fans as well as the velocity components were measured. Velocity components were measured across and around the impeller using Laser Doppler Anemometer. A computational model using the k-e turbulence model and wall function has been used to predict the internal flows of all volutes. Solving a fully 3D viscous flow was carried out using commercial CFD code, FLUENT. The results showed that volute by spread angle of 5° has the highest head and efficiency in a limited space without losing the desired mass flow rate.