Effect of Blade Wrap Angle on Performance of a Single-Channel Pump.

To study the effect of blade wrap angle on energy performance and unsteady characteristics of the single-channel pump, a single-channel pump with specific speed of 140 was selected as experimental test model and three impeller models with blade wrap angle of 290°, 340° and 390° were respectively designed. The performance of different single-channel pumps with blade wrap angle of 290°, 340° and 390° respectively were tested. Based on the experimental study, the effect of blade wrap angle on the energy characteristics, head pulsation, pressure fluctuation and radial force of the single-channel pump was obtained and analyzed. The results show that with blade wrap angle increases from 290° to 390°, the maximum pump head and efficiency gradually increases and the maximum increase amplitude is 7.3% and 7.79% respectively. The minimum static pressure at impeller outlet under three schemes all occurs at 1.0Qd and bigger blade wrap angle can reduce the mixing loss at impeller outlet. With the increase of blade wrap angle, the head pulsation and pressure fluctuation all decrease gradually. The maximum eighth section under the small flow rate and under the big flow rate occurs at the volute second the section. A higher pressure fluctuation exists around volute tongue. The time-averaged radial force decreases as the blade wrap angle increases and its increase amplitude decreases as the flow rate increases. The research fruits can provide some reference and theoretical basis for the optimization of single-channel pumps. [ABSTRACT FROM AUTHOR]