Abstract
Small-sized axial fan is used as air cooler for electric equipments. But there is demand for higher power of fan according to the increase of quantity of heat from electric device. Therefore, higher rotational speed design is necessary but it causes the deterioration of efficiency and increases the noise. Then the adoption of contra-rotating rotor for small-sized fan was proposed for the improvement of performance. In the present paper, experiment and numerical flow simulation were conducted to investigate the internal flow of conventional small-sized axial fan and contra-rotating small-sized axial fan. And the relationship between the performance and the internal flow field was clarified with the numerical analysis results at partial flow rate.
