To optimize the aerodynamic performance of the automobile cooling fan(ACF), the internal flow field of the original fan was numerically simulated. According to the theory of boundary vorticity dynamics(BVD), the distr...To optimize the aerodynamic performance of the automobile cooling fan(ACF), the internal flow field of the original fan was numerically simulated. According to the theory of boundary vorticity dynamics(BVD), the distribution laws of the boundary vorticity flux(BVF) on the blade surface and the circumferential vorticity(CV) at the wake plane of the fan were analyzed, and the underlying various negative factors, such as vortex shedding, separated flow and complicated secondary flow, on the fan blade surface and its dynamic source were diagnosed. Combined with the velocity triangle theory, the mathematical relationship between the BVF diagnosis and the geometrical characteristics of the blade profile(hereinafter referred to as profile) is used to guide the design improvement of the blade. The analysis found that at the same speed, the extension and rotation of the profile could match a smaller input torque at the same flow rate and pressure rise, thereby improving the efficiency of the fan. The test results confirmed the above conclusion. The peak efficiency of the improved fan has been increased by 2.3%, and the aerodynamic performance in the low-flow-rate has been improved. The conclusion of the study shows the applicability of the BVD theory in the diagnosis and design improvement of ACF internal flow.展开更多
基金funded by the Basic Scientific Research Funds of Central Universities and the National Science and Technology Major Project(2017-Ⅱ-0007-0021)。
文摘To optimize the aerodynamic performance of the automobile cooling fan(ACF), the internal flow field of the original fan was numerically simulated. According to the theory of boundary vorticity dynamics(BVD), the distribution laws of the boundary vorticity flux(BVF) on the blade surface and the circumferential vorticity(CV) at the wake plane of the fan were analyzed, and the underlying various negative factors, such as vortex shedding, separated flow and complicated secondary flow, on the fan blade surface and its dynamic source were diagnosed. Combined with the velocity triangle theory, the mathematical relationship between the BVF diagnosis and the geometrical characteristics of the blade profile(hereinafter referred to as profile) is used to guide the design improvement of the blade. The analysis found that at the same speed, the extension and rotation of the profile could match a smaller input torque at the same flow rate and pressure rise, thereby improving the efficiency of the fan. The test results confirmed the above conclusion. The peak efficiency of the improved fan has been increased by 2.3%, and the aerodynamic performance in the low-flow-rate has been improved. The conclusion of the study shows the applicability of the BVD theory in the diagnosis and design improvement of ACF internal flow.
