The effect of tip-blade cutting on the performance of a large scale axial fan was investigated using computational fluid dynamics(CFD)methods.Experiments verified the numerical simulations.The original fan was compare...The effect of tip-blade cutting on the performance of a large scale axial fan was investigated using computational fluid dynamics(CFD)methods.Experiments verified the numerical simulations.The original fan was compared with the one with tip-cutting in terms of dimensionless characteristic and aerodynamic performance in tip region under the conditions of the maximum efficiency point and near-stall point.The results showed that double leakage flow occurred in tip clearance at maximum efficiency point and spillage of leakage flow from leading edge occurred in tip-blade region at near-stall point for the both two fans;and that tip-cutting with 6% of blade height could reduce the intensity of tip-leakage vortex and increase flow capacity in tip blade region,and hold the stall margin almost the same as the original fan.The maximum efficiency of the fan with tip-cutting was improved by1%,and the ability of total pressure rising was obviously greater than the original fan.展开更多
In the steady operation condition, the experiments and the numerical simulations are used to investigate the tip leakage flow fields in three low pressure axial flow fans with three kinds of circumferential skewed rot...In the steady operation condition, the experiments and the numerical simulations are used to investigate the tip leakage flow fields in three low pressure axial flow fans with three kinds of circumferential skewed rotors, including the radial rotor, the forward-skewed rotor and the back- ward-skewed rotor. The three-dimensional viscous flow fields of the fans are computed. In the experiments, the two-dimensional plane particle image velocimetry （PIV） system is used to measure the flow fields in the tip region of three different pitchwise positions of each fan. The results show that the computational results agree well with the experimental data in the flow field of the tip region of each fan. The tip leakage vortex core segments based on method of the eigenmode analysis can display clearly some characteristics of the tip leakage vortex, such as the origination position of tip leak- age vortex, the development of vortex strength, and so on. Compared with the radial rotor, the other two skewed rotors can increase the stability of the tip leakage vortex and the increment in the forward-skewed rotor is more than that in the backward-skewed one. Among the tip leakage vortices of the three rotors, the velocity of the vortex in the forward-skewed rotor is th6 highest in the circumferential direction and the lowest in the axial direction.展开更多
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20113218120006)
文摘The effect of tip-blade cutting on the performance of a large scale axial fan was investigated using computational fluid dynamics(CFD)methods.Experiments verified the numerical simulations.The original fan was compared with the one with tip-cutting in terms of dimensionless characteristic and aerodynamic performance in tip region under the conditions of the maximum efficiency point and near-stall point.The results showed that double leakage flow occurred in tip clearance at maximum efficiency point and spillage of leakage flow from leading edge occurred in tip-blade region at near-stall point for the both two fans;and that tip-cutting with 6% of blade height could reduce the intensity of tip-leakage vortex and increase flow capacity in tip blade region,and hold the stall margin almost the same as the original fan.The maximum efficiency of the fan with tip-cutting was improved by1%,and the ability of total pressure rising was obviously greater than the original fan.
基金This project is supported by National Natural Science Foundation of China (No. 50406017).
文摘In the steady operation condition, the experiments and the numerical simulations are used to investigate the tip leakage flow fields in three low pressure axial flow fans with three kinds of circumferential skewed rotors, including the radial rotor, the forward-skewed rotor and the back- ward-skewed rotor. The three-dimensional viscous flow fields of the fans are computed. In the experiments, the two-dimensional plane particle image velocimetry （PIV） system is used to measure the flow fields in the tip region of three different pitchwise positions of each fan. The results show that the computational results agree well with the experimental data in the flow field of the tip region of each fan. The tip leakage vortex core segments based on method of the eigenmode analysis can display clearly some characteristics of the tip leakage vortex, such as the origination position of tip leak- age vortex, the development of vortex strength, and so on. Compared with the radial rotor, the other two skewed rotors can increase the stability of the tip leakage vortex and the increment in the forward-skewed rotor is more than that in the backward-skewed one. Among the tip leakage vortices of the three rotors, the velocity of the vortex in the forward-skewed rotor is th6 highest in the circumferential direction and the lowest in the axial direction.
