aerodynamic design and performance assessment of a centripetal-flow fan

In this paper, the aerodynamic and mechanical design of a centripetal-flow fan has been undertaken at a particular thermal environment in which the working fluid behaves as an ideal gas. a preliminary design (one-dimensional analysis) study was conducted at first, based on which three-dimensional modeling and optimization were subsequently applied to the design of the centripetal-flow fan. the aerodynamic performance of the designed fan and its operating characteristics in different working conditions were assessed by means of numerical simulations. our results suggest that isentropic efficiency and pressure ratio of the centripetal-flow fan at design operating conditions can reach 81.14% and 1.0833, respectively, which satisfy the requirements for fans in commercial and industrial applications. from the fan performance curves, it is found that as the mass flow rate increases, the efficiency of the fan operating at the designed rotational speed first increases and then decreases. there exists an optimal mass flow rate which leads to the maximum efficiency of the fan. similarly, the fan pressure ratio first increases as the mass flow rate increases, attains a maximum value and then decreases as the mass flow rate further increases. at off-design rotational speeds, although the fan characteristic curves show the same tendency as those observed at the design condition. moreover, the fan characteristic curve becomes steeper with an increased rotational speed, which means that the variations of isentropic efficiency and pressure ratio with change in mass flow rate become much greater. the results of our present study confirm the feasibility of using the centripetal-flow fan for various industrial applications.