In this article, the low pressure axial flow fan with circumferential skewed rotor blade, including the radial blade, the forward-skewed blade and the backward-skewed blade, was studied with experimental methods. The ...In this article, the low pressure axial flow fan with circumferential skewed rotor blade, including the radial blade, the forward-skewed blade and the backward-skewed blade, was studied with experimental methods. The aerodynamic performance of the rotors was measured. At the design condition at outlet of the rotors, detailed flow measurements were performed with a five-hole probe and a Hot-Wire Anemometer （HWA）. The results show that compared to the radial rotor, the forward-skewed rotor demonstrates a wider Stable Operating Range （SOR）, is able to reduce the total pressure loss in the hub region and make main loading of blade accumulating in the mid-span region. There is a wider wake in the upper mid-span region of the forward-skewed rotor. Compared to the radial rotor, in the backward-skewed rotor there is higher total pressure loss near the hub and shroud regions and lower loss in the mid-span region. In addition, the velocity deficit in the wake is lower at mid-span of the backward-skewed rotor than the forward-skewed rotor.展开更多
This article presents the flow mechanism analysis and experimental study of a forward-skewed impeller and a radial impeller in low pressure axial fan. The forward-skewed blade was obtained by the optimization design o...This article presents the flow mechanism analysis and experimental study of a forward-skewed impeller and a radial impeller in low pressure axial fan. The forward-skewed blade was obtained by the optimization design of the radial blade and CFD technique. Measurement of the two blades was carried out in aerodynamic and aeroacoustic performance. Compared to the radial blade, the forward-skewed blade has demonstrated the improvements in efficiency, total pressure ratio, Stable Operating Range （SOR） and less aerodynamic noise. Detailed flow measurement and computation were performed for outlet flow field for investigating the responsible flow mechanisms. The results show the forward-skewed blade can cause a spanwise redistribution of flow toward the blade mid-span and reduce tip loading. This results in reduced significantly total pressure loss near hub and shroud endwall region, despite the slight increase of total pressure loss at mid-span.展开更多
Based on the characteristics of axial fans of outdoor units of centralized air-conditioners, using the finite-volume method, applying three-dimensional steady Reynolds-averaged Navier-Stokes equations coupled with Spa...Based on the characteristics of axial fans of outdoor units of centralized air-conditioners, using the finite-volume method, applying three-dimensional steady Reynolds-averaged Navier-Stokes equations coupled with Spalart-Allmaras turbulence model equation, and adopting SIMPLE algorithm, numerical analysis is made and applied to analyze the internal flow field of axial rotors with skewed-swept blade at its leading edge. This numerical simulation mainly investigates the formation and development of the tip vortex. Based on the tip vortex characteristics that have been captured, the internal flow numerical results are compared with those obtained by the PIV experiments. This comparison indicates a good agreement between numerical results and PIV results, thus proving the validity of the numerical simulation. In addition, based on the internal flow analyses of the axial rotor with skewed-swept blade at its leading edge, different flow phenomena features are presented. These flow features can be used for further improvements of the present rotor performance characteristics.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.50406017).
文摘In this article, the low pressure axial flow fan with circumferential skewed rotor blade, including the radial blade, the forward-skewed blade and the backward-skewed blade, was studied with experimental methods. The aerodynamic performance of the rotors was measured. At the design condition at outlet of the rotors, detailed flow measurements were performed with a five-hole probe and a Hot-Wire Anemometer （HWA）. The results show that compared to the radial rotor, the forward-skewed rotor demonstrates a wider Stable Operating Range （SOR）, is able to reduce the total pressure loss in the hub region and make main loading of blade accumulating in the mid-span region. There is a wider wake in the upper mid-span region of the forward-skewed rotor. Compared to the radial rotor, in the backward-skewed rotor there is higher total pressure loss near the hub and shroud regions and lower loss in the mid-span region. In addition, the velocity deficit in the wake is lower at mid-span of the backward-skewed rotor than the forward-skewed rotor.
基金the National Natural Science Foundation of China (Grant No.50406017)
文摘This article presents the flow mechanism analysis and experimental study of a forward-skewed impeller and a radial impeller in low pressure axial fan. The forward-skewed blade was obtained by the optimization design of the radial blade and CFD technique. Measurement of the two blades was carried out in aerodynamic and aeroacoustic performance. Compared to the radial blade, the forward-skewed blade has demonstrated the improvements in efficiency, total pressure ratio, Stable Operating Range （SOR） and less aerodynamic noise. Detailed flow measurement and computation were performed for outlet flow field for investigating the responsible flow mechanisms. The results show the forward-skewed blade can cause a spanwise redistribution of flow toward the blade mid-span and reduce tip loading. This results in reduced significantly total pressure loss near hub and shroud endwall region, despite the slight increase of total pressure loss at mid-span.
文摘Based on the characteristics of axial fans of outdoor units of centralized air-conditioners, using the finite-volume method, applying three-dimensional steady Reynolds-averaged Navier-Stokes equations coupled with Spalart-Allmaras turbulence model equation, and adopting SIMPLE algorithm, numerical analysis is made and applied to analyze the internal flow field of axial rotors with skewed-swept blade at its leading edge. This numerical simulation mainly investigates the formation and development of the tip vortex. Based on the tip vortex characteristics that have been captured, the internal flow numerical results are compared with those obtained by the PIV experiments. This comparison indicates a good agreement between numerical results and PIV results, thus proving the validity of the numerical simulation. In addition, based on the internal flow analyses of the axial rotor with skewed-swept blade at its leading edge, different flow phenomena features are presented. These flow features can be used for further improvements of the present rotor performance characteristics.
