Effect of Stators on the Performance and the Thermal Capabilities of Small Axial Cooling Fans

This investigation examines experimentally the effect of stators on the performance curves and the heat transfer capabilities of small axial cooling fans. The experimental data indicated that the results are highly affected by the flow conditions at the fan outlet. Downstream guide vanes can be beneficial in terms of pressure drop and efficiency, and thus more economical operation, as well as,in the local heat transfer distribution at the wake of the stator blades especially when the fan is installed very close to the cooling object. However, the more jet spreading and mixing with the surroundings achieved due to the absence of stators at higher separation distances results in increased turbulent levels improving the average heat transfer rate in the stagnation region. The increase heat transfer rate, in the case of a single fan impeller (swirling jet),can be25% higher compared with the case of a typical fan stage (non-swirling jet)showing a similarity with the general trends of swirling and non-swirling impingement jets.