叶轮出口边及径向导叶结构对离心泵性能影响的数值研究

发布时间：2018-07-07 17:38

本文选题：离心泵 + 出口边倾角　；参考：《西安理工大学》2017年硕士论文

【摘要】：离心泵作为一种广泛应用的叶轮机械,目前已有大量学者对其在运行过程中存在的振动、噪音、运行效率较低和压力脉动等问题进行了相关研究并取得了大量成果。但仍然存在离心泵叶轮与导叶动静耦合处压力脉动较大,叶轮轴向力较大等问题。本文通过对一台带径向导叶的单级单吸离心泵进行模拟计算。分析叶片出口边倾角为0°、5°、10°、15°、20°工况,得出倾角为15°时,对离心泵水力效率和压力脉动强度改善效果最优。叶片出口边倾斜改型后叶轮轴向力大幅变化,对15。倾角模型泵进行了平衡叶轮轴向力的改型研究。同时为继续降低倾斜改型后离心泵内的压力脉动强度,对15。倾角模型泵,选取叶高系数为0.8、0.6、0.4的径向正导叶分别进行了改型研究。经对比发现:(1)叶片出口边倾斜改型后:小流量下随着叶片出口边倾角增大,泵的扬程下降率逐渐增大,大流量下随着叶片出口边倾角增大,泵的扬程先逐渐增大后降低。叶片出口边倾角为15°时模型泵的水力效率和压力脉动强度改善效果最优,此时模型泵的额定工况点效率提升0.41%,1.13Q流量下效率提升0.53%,扬程提升0.92%,模型泵性能曲线更平滑,模型泵的压力脉动强度较改型前下降11.1%。(2)叶轮轴向力平衡:对叶轮出口边15°倾角模型泵改变盖板直径发现,降低前盖板直径可在不影响泵水力性能的情况下较好的降低叶轮轴向力。增加后盖板直径也可以达到平衡轴向力的目的,但会对叶轮出口处的流态产生影响,小幅度降低模型泵的水力性能;(3)径向正导叶改型后:对15。倾角模型泵选择不同的正导叶叶片高度继续研究发现,选择合理的正导叶叶片高度可继续降低模型泵内的压力脉动强度。当正导叶叶高系数为0.6时各监测点平均压力脉动强度系数最低,较改型前下降11.0%。但降低正导叶叶片高度会使离心泵的高效区域逐渐变窄,径向导叶的扩压能力逐渐下降。
[Abstract]:As a kind of widely used impeller machinery, a large number of scholars have studied the problems of vibration, noise, low efficiency and pressure pulsation in the process of operation. However, there are still some problems such as greater pressure fluctuation and greater axial force at the coupling of impeller and guide vane. In this paper, a single stage single suction centrifugal pump with diameter guide blade is simulated. In this paper, the working conditions of blade outlet slope angle 0 掳5 掳10 掳10 掳15 掳15 掳20 掳are analyzed. When the angle is 15 掳, the effect of improving hydraulic efficiency and pressure pulsation intensity of centrifugal pump is the best. The axial force of the impeller changed greatly after the blade exit edge tilted and modified. In this paper, the modification of axial force of impeller is studied. At the same time, in order to continue to reduce the pressure pulsation intensity in the centrifugal pump after tilting modification, 15. The radial positive guide vane with the blade height coefficient of 0.8 and 0.6% was selected for the model pump and the modification of the radial positive guide vane was carried out. The results show that: (1) after the blade exit edge tilting modification, the head drop rate of the pump increases gradually with the increase of the blade outlet slope angle under the small flow rate, and with the increase of the blade outlet edge inclination angle at the large flow rate, the pump head increases first and then decreases. The hydraulic efficiency and pressure pulsation intensity of the model pump are the best when the angle of blade outlet slope is 15 掳. At this time, the efficiency of the model pump is increased by 0.53 at the rated working point of 0.41 and 1.13Q, and the lift is increased by 0.92.The performance curve of the model pump is smoother. The pressure pulsation intensity of the model pump is lower by 11.1 than that before the modification. (2) Axial force balance of the impeller: the model pump with 15 掳inclination at the outlet edge of the impeller is found to change the cover plate diameter. Reducing the diameter of the front cover plate can reduce the axial force of the impeller without affecting the hydraulic performance of the pump. Increasing the diameter of the back cover plate can also achieve the purpose of balancing axial force, but it will affect the flow state at the outlet of the impeller, and reduce the hydraulic performance of the model pump by a small margin. (3) after the modification of the radial positive guide vane: 15. It is found that the pressure pulsation intensity in the model pump can continue to be reduced by selecting the reasonable height of the positive vane blade with different height of the positive guide vane in the model pump. When the height coefficient of the positive guide blade is 0.6, the mean pressure pulsation intensity coefficient of each monitoring point is the lowest, which is 11.0% lower than that before modification. But decreasing the vane height of the positive guide vane will narrow the high efficiency area of centrifugal pump and decrease the diffusing capacity of the guide blade.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH311

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