Abstract: Study is carried out on twisted blade for micro cooling axial fan. By introducing an aerodynamic parameter called twisted power α, a differential equation and its corresponding boundary condition are established to determine the radial distribution of the through-flow velocity. Some analytic solutions are presented and discussions are also given about their influence on the shape of the twisted blade. Moreover, according to the running characteristics of the micro cooling axial fan, a restricted condition for the twisted power is proposed, by which a minimum value of the twisted power can be simultaneously obtained and the concrete value is determined by factors such as the fan’s aerodynamic load and the geometric shape of micro fan. The numerical investigation is implemented by using computational fluid dynamics (CFD) to study the aerodynamic performance of the micro fans designed by different twisted powers. Result indicates, decreasing the twisted power may increase the pressure of the micro fan and thus improve its cooling ability. So the minimum of the twisted power satisfying the restricted condition is the optimum value for the design of the twisted blade of micro fan.

Key words: Aerodynamic performance, Micro fan, Twisted blade, Twisted power