离心泵关死点性能的研究
发布时间：2018-10-26 14:40
【摘要】：随着社会经济的飞速发展,现代很多离心泵的设计都对关死点性能提出了越来越明确的要求,比如核电用泵、舰船用泵和可再生能源泵等。由于传统离心泵设计对于关死点性能一般不予考虑,导致目前有关离心泵关死点性能的研究相当缺乏。因此,迫切需要开展离心泵关死点性能的研究以丰富和发展现代离心泵设计理论和方法。本文在国家自然科学基金(51079062、51109095)的资助下,采用理论分析、数值计算与试验测试相结合的方法对离心泵关死点的特性进行了较为系统的研究,主要工作和创造性成果有： 1.较为系统地总结了离心泵关死点性能、内流模拟、PIV测试、流固耦合计算、流动诱导振动以及性能预测的研究现状及其发展趋势。 2.首次试验研究了离心泵叶轮叶片出口角、叶片出口宽度、叶片数、叶片包角和叶片进口冲角等叶轮主要几何参数对离心泵关死点扬程和关死点功率的影响规律,并根据各参数引起的关死点扬程及关死点功率的变化范围对各参数的影响大小进行了排序。各参数对关死点扬程影响从大到小的顺序依次为：叶片包角、叶片出口宽度、叶片数、叶片进口冲角和叶片出口角。各参数对关死点功率影响从大到小的顺序依次为：叶片出口宽度、叶片包角、叶片数、叶片出口角和叶片进口冲角。 3.在总结研究离心泵关死点扬程计算方法的基础上,以34台离心泵关死点扬程的试验数据为依据,采用一元非线性回归分析方法对7种常用的离心泵关死点扬程计算方法进行了修正。实例计算表明修正后各公式的计算精度得到了明显提高。 4.首次基于BP人工神经网络建立了离心泵关死点功率的预测模型,并给出了网络的输入模式和拓扑结构。采用46组不同比转数离心泵结构参数和关死点性能参数对网络模型进行了训练,采用另外3组不同比转数的离心泵模型对网络进行了检验,检验结果表明网络平均预测偏差为4%,具有比较高的工程应用价值。 5.建立了离心泵关死点内流数值模拟方法,并对3台不同比转数的离心泵在关死点工况下的内部流动进行了全流场数值计算,基于数值模拟结果预测了各模型泵关死点扬程以及各模型泵过流部件内的流动结构与压力脉动规律。研究结果表明：(1)各模型关死点扬程预测值与试验值偏差均在5%以内,这说明提出的数值模拟方法是基本正确的；(2)叶轮内不稳定流动对进口管路内流的影响距离约为管径的10倍；叶频对进口管路压力脉动基本没有影响,轴频对进口管路内压力脉动有影响但比较小；(3)在关死工况下,随着比转数的增加叶轮出口处的漩涡面积比例有逐渐减小的趋势,而叶轮进口的漩涡面积比例有逐渐增大的趋势,同时叶轮出口的“射流-尾迹”现象也越来越明显；轴频对叶轮进口压力脉动影响较大,叶轮出口的压力脉动则受叶频的影响较大；蜗壳内各点的压力脉动最大幅值都是出现在叶频处,这说明动静干涉对蜗壳内的压力脉动有着较大的影响；(4)出口管路内各点压力脉动曲线基本一致,各曲线波峰波谷数与各模型叶片数相等,同时其最大幅值均出现在叶频处。 6.对一比转数为65的离心泵关死点内部流动进行了PIV测试,并将内流测试结果与数值模拟结果进行了详细对比。对比结果表明除叶轮进口附近流场外,PIV试验测得的内流场与数值模拟计算得到的内流场都较为一致；叶轮进口流场的差异很有可能是PIV示踪粒子沉降而导致的。 7.对一比转数为46.2的离心泵关死点工况下的结构场和内流场进行了流固耦合数值计算,对比了流固耦合前后关死点扬程预测精度和泵内流场分布的差异,并详细分析了叶轮的结构变形。研究结果表明：(1)考虑流固耦合作用后关死点扬程的预测精度有所提高；(2)考虑流固耦合作用后叶轮内各监测点的压力脉动现象呈现出明显的周期性且脉动幅度也明显增大；(3)叶轮盖板上越靠近隔舌的区域,其位移变形和等效应力越大；各叶片的位移变形从进口到出口逐渐增大,但各叶片的等效应力最大值并不在叶片出口边。 8.采用加速度传感器对一比转数为65的离心泵关死工况下的流动诱导振动进行了测试,并对试验结果进行了详细分析。试验结果表明：(1)轴向振动加速度脉动呈现一定的弱周期性规律,径向振动加速度脉动没有任何周期性；(2)蜗壳隔舌处的振动加速度脉动幅值最大；(3)各测点的最大振动加速度均出现在1400Hz附近,大约是叶片通过频率的10倍；(4)蜗壳5断面处的轴向振动程度是最为剧烈的,而7断面处的径向振动程度是最弱的。
[Abstract]:With the rapid development of social economy, the design of many modern centrifugal pumps has put forward more and more definite demands on the performance of shut-off point, such as nuclear power pump, ship pump and renewable energy pump, etc. Because the traditional centrifugal pump design is generally not considered for shut-off point performance, the research on the performance of the dead point of the centrifugal pump is quite scarce at present. Therefore, it is urgent to carry out the research on the dead-point performance of centrifugal pump to enrich and develop modern centrifugal pump design theory and method. With the help of National Natural Science Foundation of China (51079062, 51109095), the characteristics of the dead point of centrifugal pump are systematically studied by means of theoretical analysis, numerical calculation and test test. 1. The research status and development of the dead point performance, internal flow simulation, PIV measurement, flow solid coupling calculation, flow induced vibration and performance prediction of centrifugal pump are systematically summarized. 2. For the first time, the main geometric parameters of impeller blade outlet angle, blade outlet width, number of blades, blade package angle and blade inlet offset angle are studied in this paper. The influence law of each parameter is affected by the variation range of the dead-point head and the dead-point power caused by each parameter. The sequence of the influence of each parameter on the dead-point lift is as follows: blade package angle, blade outlet width, number of blades, blade inlet punching angle, The influence of each parameter on the off-dead point power is: blade outlet width, blade package angle, number of blades, blade outlet angle and leaf. On the basis of summarizing the calculation method of the dead-point lift of centrifugal pump, based on the test data of 34 centrifugal pumps off dead-point lift, the dead-point head of seven commonly used centrifugal pumps is calculated by one-way nonlinear regression analysis method. The calculation method is modified, and the calculation of each formula after correction is calculated by the example calculation. 4. The prediction model of dead point power of centrifugal pump is established based on BP artificial neural network for the first time, and the network is given. In this paper, the network model is trained by the structure parameters and the off-dead point performance parameters of the centrifugal pump with different ratios of 46 groups, and the network is tested by the centrifugal pump model with different ratios of 3 different ratios. The results show that The network average forecast deviation is 4%. The numerical simulation method of the flow in the dead point of the centrifugal pump is established, and the centrifugal pump with different specific revolutions is under the condition of closing dead point. The whole flow field numerical calculation is carried out in the internal flow. Based on the numerical simulation results, the dead-point lift of each model pump and the flow-through part of each model pump are predicted. The results show that: (1) the deviation of the prediction value and the test value of the dead point of each model is within 5%, which indicates that the proposed numerical simulation method is basically correct; (2) the unsteady flow in the impeller is within the inlet pipeline. The influence distance of flow is about 10 times of pipe diameter; leaf frequency has no effect on the pressure pulsation of inlet pipeline, but the axial frequency has an influence on the pressure pulsation in inlet pipeline but small; (3) Under the dead working condition, with the increase of the number of revolutions, the impeller outlet is increased The swirl area ratio has a decreasing trend, while the proportion of the vortex area of the impeller inlet is increasing gradually, and the 鈥渏et-tail trace鈥，
本文编号：2296058
[Abstract]:With the rapid development of social economy, the design of many modern centrifugal pumps has put forward more and more definite demands on the performance of shut-off point, such as nuclear power pump, ship pump and renewable energy pump, etc. Because the traditional centrifugal pump design is generally not considered for shut-off point performance, the research on the performance of the dead point of the centrifugal pump is quite scarce at present. Therefore, it is urgent to carry out the research on the dead-point performance of centrifugal pump to enrich and develop modern centrifugal pump design theory and method. With the help of National Natural Science Foundation of China (51079062, 51109095), the characteristics of the dead point of centrifugal pump are systematically studied by means of theoretical analysis, numerical calculation and test test. 1. The research status and development of the dead point performance, internal flow simulation, PIV measurement, flow solid coupling calculation, flow induced vibration and performance prediction of centrifugal pump are systematically summarized. 2. For the first time, the main geometric parameters of impeller blade outlet angle, blade outlet width, number of blades, blade package angle and blade inlet offset angle are studied in this paper. The influence law of each parameter is affected by the variation range of the dead-point head and the dead-point power caused by each parameter. The sequence of the influence of each parameter on the dead-point lift is as follows: blade package angle, blade outlet width, number of blades, blade inlet punching angle, The influence of each parameter on the off-dead point power is: blade outlet width, blade package angle, number of blades, blade outlet angle and leaf. On the basis of summarizing the calculation method of the dead-point lift of centrifugal pump, based on the test data of 34 centrifugal pumps off dead-point lift, the dead-point head of seven commonly used centrifugal pumps is calculated by one-way nonlinear regression analysis method. The calculation method is modified, and the calculation of each formula after correction is calculated by the example calculation. 4. The prediction model of dead point power of centrifugal pump is established based on BP artificial neural network for the first time, and the network is given. In this paper, the network model is trained by the structure parameters and the off-dead point performance parameters of the centrifugal pump with different ratios of 46 groups, and the network is tested by the centrifugal pump model with different ratios of 3 different ratios. The results show that The network average forecast deviation is 4%. The numerical simulation method of the flow in the dead point of the centrifugal pump is established, and the centrifugal pump with different specific revolutions is under the condition of closing dead point. The whole flow field numerical calculation is carried out in the internal flow. Based on the numerical simulation results, the dead-point lift of each model pump and the flow-through part of each model pump are predicted. The results show that: (1) the deviation of the prediction value and the test value of the dead point of each model is within 5%, which indicates that the proposed numerical simulation method is basically correct; (2) the unsteady flow in the impeller is within the inlet pipeline. The influence distance of flow is about 10 times of pipe diameter; leaf frequency has no effect on the pressure pulsation of inlet pipeline, but the axial frequency has an influence on the pressure pulsation in inlet pipeline but small; (3) Under the dead working condition, with the increase of the number of revolutions, the impeller outlet is increased The swirl area ratio has a decreasing trend, while the proportion of the vortex area of the impeller inlet is increasing gradually, and the 鈥渏et-tail trace鈥，
本文编号：2296058
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