多级离心泵流动诱导辐射噪声研究

发布时间：2018-05-26 17:32

本文选题：多级离心泵 + 辐射噪声　；参考：《江苏大学》2017年硕士论文

【摘要】：本文的研究工作是在国家自然科学基金项目“离心泵进口畸变流诱导噪声作用机理研究”(编号:51509108)、江苏省自然科学基金项目“离心泵低噪声水力优化设计及关键技术研究”(编号:BK20150516)、中国博士后科学基金项目“多级离心泵流动诱导结构噪声分析及声优化设计研究”(编号:2015M581735)的资助下展开。多级离心泵是提供高扬程、高压力液体输送的重要设备,广泛应用于高层建筑给水、海水淡化、深海石油开采等国民经济重要领域。由于离心泵内部流动复杂,在多级离心泵中还存在着级间耦合问题,导致其在工作过程中常产生较大的振动和噪声。近年来,噪声污染已经成为与空气污染、水污染和垃圾污染并列的四大污染之一,随着人们生活质量的提高和中国城市化建设步伐加快,人们对工作和居住环境提出越来严格的要求,因此,对多级离心泵流动诱导辐射噪声进行研究具有重要的理论意义和工程应用价值。本文在某多级离心泵样机基础上,对模型泵进行了流场和声场数值计算,并在半消声室内进行了模型泵外特性和辐射噪声实验测试;基于数值计算和实验结果,对模型泵叶轮和导叶匹配关系进行优化设计,对比分析优化前后多级离心泵流场和声学性能。本文的主要研究内容和成果如下:1.分析了多级离心泵噪声源分布,系统阐述了国内外研究现状。通过对原型样机进行局部简化得到模型泵,并对模型泵进行流场定常和非定常数值计算,对比分析多级离心泵流场速度、压力分布,以及压力脉动特征,流场数值计算结果表明:多级离心泵扬程和效率的模拟值与实验值变化规律基本一致,扬程的相对误差为4.5%,效率的相对误差为3.8%;在同一流量下,从首级叶轮到末级叶轮,叶轮的进口入流条件逐渐变差,0.6Qd工况下多级离心泵内漩涡最多,随着流量增加,叶轮和正反导叶流道内漩涡数量逐渐减少;多级离心泵压力脉动分析结果表明:各级正导叶流道内压力脉动强度最大,叶轮流道最小,且某些测点之间压力脉动强度有着较大的跳跃性;导叶流道内压力脉动主频为叶频(327Hz),在小流量工况下,出现较多小于叶频的低频脉动。2.在流场非定常计算基础上,基于声学有限元方法,对多级离心泵进行流动诱导辐射噪声数值计算,分析不同流量下多级离心泵辐射噪声变化规律,并与实验值进行对比,可以得出以下结论:多级离心泵辐射噪声主频为叶频(327Hz),随着流量增加,辐射噪声平均总声压级先减小后增大,在0.8Qd附近达到最小;多级离心泵辐射噪声在首级导叶附近最大,而在末级导叶附近最小;不同工况下,叶频下多级离心泵流动诱导辐射噪声指向性均呈现出偶极子特性。3.在半消声室内搭建多级离心泵辐射噪声实验台,首先进行了多级离心泵外特性实验,在此基础上进行多级离心泵辐射噪声实验,主要结论有:随着流量增加,有无电机隔音罩时,多级离心泵辐射噪声总声压级先增加再减小后增加,均在0.8Qd工况附近总声压级达到最小,在1.2Qd工况附近达到最大,且在两种实验条件下辐射噪声总声压级大约相差2dB;随着泵运行转速线性增加,多级离心泵辐射噪声总声压级也近似呈线性增加规律;多级离心泵辐射噪声指向性表现出偶极子特性,说明偶极子是多级离心泵辐射噪声的主要声源类型。4.在模型泵数值计算和实验基础上,对叶轮和导叶之间的匹配关系进行优化设计,并完成流场和声场数值计算,对比分析了优化前后多级离心泵外特性能、流场分布、辐射噪声特性,计算结果表明:设计流量下,优化前后多级离心泵扬程提高了19.2%,效率提高了12.9%,且最高效率点出现在1.1Qd附近,高效区得到拓宽;优化后多级离心泵流场速度分布更加均匀,漩涡数量明显减少;优化后的多级离心泵,在相同位置处的压力脉动强度比优化前相应减小,且各测点之间压力脉动变化较为平缓;优化后的多级离心泵辐射噪声主频仍为叶频,但叶频声压级比优化前减小2dB,平均总声压级比优化前减小3.5dB,这表明本文所采用的优化方法对于多级离心泵降噪是有效的。
[Abstract]:The research work of this paper is "study on the mechanism of induced noise induced by centrifugal pump inlet distortion" in the National Natural Science Foundation Project (number: 51509108). The Jiangsu Natural Science Foundation Project "low noise hydraulic optimization design and key technology research for centrifugal pumps" (number: BK20150516), China Post Doctoral Science Fund Project "multistage centrifugation" The pump flow induced structural noise analysis and sound optimization design research "(number: 2015M581735) is supported. The multistage centrifugal pump is an important equipment for providing high lift and high pressure liquid transportation. It is widely used in high building water supply, seawater desalination, deep sea oil mining and other important economic fields. Because of the complex internal flow of centrifugal pumps, There is still a problem of interstage coupling in the multistage centrifugal pump, which leads to the larger vibration and noise in the working process. In recent years, the noise pollution has become one of the four major pollution of the air pollution, water pollution and garbage pollution. With the improvement of people's quality of life and the quickening pace of China's urbanization construction, people are working on the work. The research on the flow induced radiation noise of multistage centrifugal pump is of great theoretical significance and engineering application value. In this paper, the numerical calculation of flow field and sound field of the model pump is carried out on the basis of a multistage centrifugal pump prototype, and the external characteristics of the model pump are carried out in the semi anechoic chamber. Experimental test of radiation noise; based on the numerical calculation and experimental results, the matching relationship between the impeller and the guide vane of the model pump is optimized. The flow field and acoustic performance of the multistage centrifugal pump before and after the optimization are compared and analyzed. The main contents and results of this paper are as follows: 1. the distribution of the noise source of the multistage centrifugal pump is analyzed, and the research status at home and abroad is systematically expounded. The model pump is obtained by partial simplification, and the flow field velocity, pressure distribution and pressure pulsation characteristics of the multistage centrifugal pump are compared and analyzed. The numerical results of the flow field show that the variation of the simulated value and the experimental value of the multistage centrifugal pump is basically the same as the experimental value. The relative error of the lift is 4.5% and the relative error of the efficiency is 3.8%. Under the same flow, the inlet flow condition of the impeller is gradually reduced from the first impeller to the last stage impeller. The whirlpool in the multistage centrifugal pump is the most in the 0.6Qd condition. With the increase of the flow, the number of whirlpools in the impeller and the positive and negative guide vane gradually decreases; the pressure pulsation of the multistage centrifugal pump is also fluctuating. The results show that the pressure pulsation intensity is the largest in the normal guide vane flow channel at all levels, the impeller flow channel is the smallest, and the pressure pulsation intensity between some measuring points is more hopping; the main frequency of the pressure pulsation in the guide vane flow channel is 327Hz. In the small flow condition, the low frequency pulsating low frequency pulsating.2. appears on the unsteady flow field of the flow field. Based on the acoustic finite element method, the numerical calculation of the flow induced radiation noise of the multistage centrifugal pump is carried out to analyze the radiation noise changes of the multistage centrifugal pump under different flow rates. And compared with the experimental values, the following conclusion can be drawn: the main frequency of the radiation noise of the multistage centrifugal pump is 327Hz, with the increase of the flow rate, the average total sound pressure of the radiation noise. The radiation noise of the multistage centrifugal pump is the largest near the first guide blade, but the smallest near the final guide blade. Under the different working conditions, the directivity of the flow induced radiation noise in the multistage centrifugal pump under the blade frequency is all dipole characteristic.3. in the semi anechoic chamber to set up the multistage centrifugal pump radiation noise experimental platform under the different working conditions. First, the experiment of multi stage centrifugal pump characteristics is carried out. On this basis, the radiation noise experiment of multistage centrifugal pump is carried out. The main conclusions are as follows: with the increase of flow rate, the total acoustic pressure level of the radiation noise of the multistage centrifugal pump increases first and then increases when there is no motor sound insulation cover, and the total acoustic pressure level near the 0.8Qd condition is minimum and reaches the 1.2Qd working condition. To the maximum, the total acoustic pressure level of radiation noise in the two experimental conditions is approximately 2dB, and with the linear increase of the pump operating speed, the total acoustic pressure level of the radiation noise of the multistage centrifugal pump is also approximately linearly increasing, and the directivity of the radiation noise of the multistage centrifugal pump shows the dipole characteristic, which indicates that the dipole is the main sound of the radiation noise of the multistage centrifugal pump. Based on the numerical calculation and experiment of the model pump, the source type.4. optimizes the matching relationship between the impeller and the guide vane, and completes the numerical calculation of the flow field and the sound field, and compares and analyzes the external special performance, the flow field distribution and the radiation noise characteristics of the multistage centrifugal pump before and after the optimization. The calculation results show that the multi-stage centrifugal pump before and after the design flow is optimized. The lift is increased by 19.2%, the efficiency is increased by 12.9%, and the highest efficiency point appears near 1.1Qd, and the high efficiency area is widened. The flow velocity distribution of the multistage centrifugal pump is more uniform and the number of whirlpools decreases obviously after the optimization; the pressure pulse strength at the same position decreases correspondingly and the pressure between the measured points at the same position and the pressure between the measured points after the optimization. The fluctuation of the pulsation is relatively gentle, and the main frequency of the radiation noise of the optimized multistage centrifugal pump is still the blade frequency, but the sound pressure level of the blade is reduced by 2dB, and the average total acoustic pressure level is less 3.5dB than that before the optimization, which shows that the optimization method used in this paper is effective for the noise reduction of the multistage centrifugal pump.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH311

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