摘要
为改善筒袋泵水动力性能,基于SST k-ω湍流模型,对立式筒袋泵首级叶轮进行三维非定常数值模拟,采用时-频域数据处理法,对各个监测点的压力脉动进行分析,主要研究了同一叶轮模型下蜗壳不同截面的压力脉动情况及不同交错角对离心泵内压力脉动和径向力的影响。结果表明:在三隔舌三通道蜗壳内,每隔120°压力脉动情况相似;随着交错角度的增加,距离隔舌较近且顺着叶片旋转方向的监测点压力脉动下降最多,压力脉动标准差下降了85%以上;叶轮所受径向力最多下降了60%;叶片交错后液体在轴向方向上会更容易产生流动,导致流动损失但有助于平稳蜗壳内的压力。综上所述,采用交错叶片有助于提高筒袋泵水动力性能。该研究为交错叶片结构在筒袋泵中的应用提供了参考。
Vibration and noise usually happens during the centrifugal pump running because of the interference between impeller blades and tongue. There are three tongues in the volute of barrel pump primary impeller, it makes the interference between impeller and tongue stronger, leading more serious vibration and noise, even reducing the service life of equipment. Three dimensional unsteady numerical simulations with SST k-ω turbulence model is used in barrel pump primary impeller. In order to research the influences of blade stagger angle to reduce the barrel pump vibration and noise, enhance hydrodynamic performance and improve the equipment operation stability and service life. To ensure the accuracy of the calculation results, constant calculate is used in centrifugal pump original model in the first place, considering the grid independence and compare the different of calculated value and experimental value. Centrifugal pump external characteristic experiment according to GB/T 3216-2005. The results show that performance curves trend of them is consistently, maximum deviation is about 5%, head and efficiency curves within 3% deviation at most of the flow point, results of numerical simulation has good reliability in general. The impeller rotated for 6 cycles in the simulation and the total computation time is 0.243 s. The simulation result of the last one period was used to analyze the pressure fluctuation in the pump. Pressure fluctuation of different monitor points analyzed by time-frequency domain data processing method. Pressure fluctuation at different volute cross-section of same impeller model and the influence of different stagger angle to pressure fluctuation and radial force was researched. The simulation results show that head of centrifugal pump most falls nearly 7% after using staggered blade impeller as the stagger angle increases. The efficiency of 30°stagger angle model is about 5% higher than 0°stagger angle model in low flow rate condition. The monitor point pressure and pressure fluctuation in three-channel volute is similar every 120°, most violent point is 30°after the tongue, follow the impeller rotation direction. As the stagger degree increases, pressure fluctuation of monitor point close tongue and follow the impeller rotation direction decline most in the volute, standard deviation of pressure decline more than 85%. The standard deviation of other monitor point pressure in the volute also decline more than 50%. The reason is fluid highest radial velocity average distribution along axial direction reduce about 20% at impeller outlet, flow instability cause by fluid impact tongue more less. Pressure fluctuation frequency is mainly affected by the blade passing frequency in the volute, it has the trend of shift to higher frequency as the blade stagger angle increase. Radial force on the impeller most reduce about 60% when stagger angle increase from 0 to 30°. Liquid will be more prone to flow in axial direction after blade staggered, leading the reduce of centrifugal pump head and efficiency but smooth the pressure inside the volute. From the discussion above, staggered blades is useful to improve pressure fluctuation situation in the volute, reduce radial force on the impeller but cause the loss of centrifugal pump head and efficiency.
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2015年第23期51-59,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金资助项目(51476144)
浙江省自然科学基金(LQ15E050005)
关键词
离心泵
模型
数值模拟
筒袋泵
交错叶片
三隔舌蜗壳
压力脉动
径向速度
centrifugal pumps
models
computer simulation
barrel pump
staggered blades
three-channel volute
pressure fluctuation
radial velocity
