Unstructured grid generators are becoming more popular among engineers, due to the significant amount of time that can be saved by using them. They provide a great flexibility in the treatment of any kind of geometry, with minimal interaction from the user. However, it is important that the user selects an appropriate cell shape from the list of available cell topologies supported by the simulation tool. This important choice depends on a combination of flow physics, available computational resources and the complexity of the geometry. Applying a proper mesh configuration to CFD simulations leads to better numerical stability and faster convergence of the solution. Choosing an appropriate turbulence model is another important factor in improving the accuracy of a simulation. Turbulence models should be selected according to the computational effort, required accuracy, physics of the flow etc. In this study performance curves of Radial fans with forward curved blades, which are also called Sirocco fans, are obtained by performing CFD simulations. Sirocco fans are capable of delivering considerably greater volumetric flow rates and also produce higher static pressure than many other centrifugal fan types of the same size and speed (but at the expense of lower overall efficiencies). Sirocco fans are often used in small furnaces, electronic equipment, heating, ventilation, and air conditioning (HVAC) applications. The lower efficiencies of sirocco fans are an inevitable consequence of the the recirculation zones that form between the blade channels of the fan. In this presentation, simulation results are presented in two parts, the first includes results of the simulations performed using different turbulence models, with the second addressing the influence of mesh configuration (utilising meshes that cover the majority of combinations of cell topology available).