Aerodynamic Optimization In the Rotor of Centrifugal Fan Using Combined Laser Doppler Anemometry and CFD Modeling

The fan under consideration is forward-curved centrifugal fan used in an air-conditioner in order to investigate an integrated scheme, consisting of shape optimization, experimental verification and numerical simulation. The targeted topic in this particular study is the design optimization of a centrifugal fan in order to improve efficiency and rectify the non-uniformity of the flow and to eliminate the vortices that are generated by the existence of inlet distortion. Two types of rotor were used by different geometries in the current study: cylindrical and conical frustum-shaped. Numerical simulation was performed by a 3D turbulent, steady-state, incompressible flow analysis. The overall experiments were conducted in a standard ISO 5801:1997 test chamber apparatus. To obtain the occurring flow patterns inside the test section from the experimental data, the optical measurement technique Laser Doppler Anemometry (LDA) is applied in the analysis and they were used to validate the CFD simulations. The comparison of the results presented a great dependence of the rotor shape and the fan efficiency. Accordingly, the results indicate that, a conical frustum-shaped rotor with the optimal cone angle can cause a higher efficiency and performance than a cylindrical design at the similar conditions. Furthermore, the findings have revealed velocity components and a jet-wake pattern at the rotor outlet. The simulations were performed at realistic conditions and the numerical results agree well with the experiments.