Abstract
Squirrel cage fan is a special type of turbo machines commonly used in industries and buildings (as a part of heating, ventilation and air conditioning (HVAC) systems). There are lots of important parameters that can affect the performance and efficiency (energy consuming). Experiments have shown that there are some turbulent areas in volute and impeller, and also in few cases, the relationships between the fan parameters, geometry and nondimensional parameters, and turbulent areas or performances were defined.
In this paper, the effect of inlet-nozzle diameter on performance and flow pattern is considered. Three inlet nozzle sizes with respect to impeller size were chosen (smaller, nearly same, and bigger than inner impeller diameter), and numerical simulations with different turbulence models were performed to find the effect of inlet size on flow pattern, performance, and efficiency. For the validation of numerical results, some experiments were done, and all the performance parameters were compared to that of numerical results. These results showed good matching between experimental and numerical results. From each case study, flow pattern and its mechanism and the reasons of low efficiency are studied and presented.
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