Based on the engineering application, the angle range of rectifying airflow unit attaching diffusion tank is from 2.5° to 7.5°. In the range of average inlet velocity of 25.0 m/s to 55.0 m/s of diffusion tan...Based on the engineering application, the angle range of rectifying airflow unit attaching diffusion tank is from 2.5° to 7.5°. In the range of average inlet velocity of 25.0 m/s to 55.0 m/s of diffusion tank, numerical simulations of diffusion tank were done. The results of numerical simulations of diffusion tank are shown as follows： ③ In cases of the inlet velocity range from 25.0 m/s to 55.0 m/s, and the angle range of rectifying airflow unit from 2.5° to 7.5°, the average value of pressure losses decreases to the minimum when the angle is 4.5°.② In cases of the inlet velocity of 35.0 m/s, the pressure loss of diffusion tank decreases to the minimum when the angle of rectifying airflow unit is 5.5°. ③ As far as there are different angles of rectifying airflow unit, pressure loss increases gradually along with the addition of inlet velocity.展开更多
In the recent past, experimental studies have shown some advantages of blade lean and sweep in axial compressors. As most of the experimental results are combined with other features, it is difficult to determine the ...In the recent past, experimental studies have shown some advantages of blade lean and sweep in axial compressors. As most of the experimental results are combined with other features, it is difficult to determine the effect of individual parameters on the performance of the compressor. The present numerical studies are aimed at understanding the performance and three-dimensional flow pattern at the exit of swept and unswept rotors. Three rotors, namely; unswept, 200 forward swept and 200 backward swept rotors are analysed with a specific intention of understanding the pattern of the blade boundary layer flow. The analysis was done using a fully three-dimensional viscous CFD code CFX-5. Results indicated reduction in pressure rise with sweep. Backward sweep is detrimental as far as the performance near endwalls is considered. On the other hand total pressure loss in the wake in mid span region is less with backward sweep, which favours its application here. However, backward sweep adversely affects the stall margin. The ability of the forward sweep to deflect the streamlines towards hub gets diminished at low flow rates. Forward sweep changes the streamline pattern in such a way that the suction surface streamlines are deflected towards the hub and the pressure surface streamlines are deflected towards the easing. An opposite behaviour is observed in backward swept rotors.展开更多
基金Supported by the National Natural Science Foundation of China （51074073） the Project of Hunan Provincial Science ＆ Technology Department （2010XK6066） the Project of Scientific Research Fund of Hunan Provincial Education Department （10C0675）
文摘Based on the engineering application, the angle range of rectifying airflow unit attaching diffusion tank is from 2.5° to 7.5°. In the range of average inlet velocity of 25.0 m/s to 55.0 m/s of diffusion tank, numerical simulations of diffusion tank were done. The results of numerical simulations of diffusion tank are shown as follows： ③ In cases of the inlet velocity range from 25.0 m/s to 55.0 m/s, and the angle range of rectifying airflow unit from 2.5° to 7.5°, the average value of pressure losses decreases to the minimum when the angle is 4.5°.② In cases of the inlet velocity of 35.0 m/s, the pressure loss of diffusion tank decreases to the minimum when the angle of rectifying airflow unit is 5.5°. ③ As far as there are different angles of rectifying airflow unit, pressure loss increases gradually along with the addition of inlet velocity.
文摘In the recent past, experimental studies have shown some advantages of blade lean and sweep in axial compressors. As most of the experimental results are combined with other features, it is difficult to determine the effect of individual parameters on the performance of the compressor. The present numerical studies are aimed at understanding the performance and three-dimensional flow pattern at the exit of swept and unswept rotors. Three rotors, namely; unswept, 200 forward swept and 200 backward swept rotors are analysed with a specific intention of understanding the pattern of the blade boundary layer flow. The analysis was done using a fully three-dimensional viscous CFD code CFX-5. Results indicated reduction in pressure rise with sweep. Backward sweep is detrimental as far as the performance near endwalls is considered. On the other hand total pressure loss in the wake in mid span region is less with backward sweep, which favours its application here. However, backward sweep adversely affects the stall margin. The ability of the forward sweep to deflect the streamlines towards hub gets diminished at low flow rates. Forward sweep changes the streamline pattern in such a way that the suction surface streamlines are deflected towards the hub and the pressure surface streamlines are deflected towards the easing. An opposite behaviour is observed in backward swept rotors.
