高效低振动循环泵设计与试验研究

发布时间：2018-06-13 17:35

本文选题：循环泵 + 正交试验　；参考：《江苏大学》2013年博士论文

【摘要】：本文是在国家杰出青年科学基金(50825902)资助下开展工作。循环泵是应用最广泛的离心泵之一,主要用于暖通空调和家用热水循环系统。目前循环泵主要存在效率较低、振动噪声水平较高等问题。随着新能效法规的出台和用户对振动噪声指标的更高要求,如何在传统离心泵设计方法的基础上,通过优化几何参数提高循环泵的水力效率和降低循环泵的振动噪声水平,成为一个重要的研究课题。本文采用理论分析、数值计算和试验验证相结合的方法对循环泵水力性能和振动噪声特性进行了研究,旨在于建立一套基于CFD的高效低振动循环泵水力设计方法。本文的主要工作和创造性成果有： 1.在传统离心泵设计方法的基础上,在保证流量、扬程不变的前提下,通过优化设计转速,使设计比转速位于40～70的高效区,并结合正交试验对循环泵的关键水力部件叶轮和蜗壳进行优化设计,采用理论分析和数值计算的方法对循环泵的水力性能指标和振动特性进行研究。结果表明：优化后B50和C100循环泵的泵效率分别为82.3%和81.1%,满足了设计能效指标要求并且超过了欧洲标准定义的离心泵最高可实现效率指标。同时,较高的转速,降低了叶轮的外径,使循环泵整体结构更为紧凑,进而降低了生产制造成本。 2.改进了循环泵蜗壳水力损失数学模型,考虑了叶轮与蜗壳间过渡段内的水力损失及螺旋蜗壳内的扩散损失,预测循环泵整体水力性能,指导蜗壳水力优化设计,试验表明：蜗壳水力损失数学模型能较为准确地预测循环泵内的水力损失,计算损失误差控制在5%之内。 3.结合正交试验和数值计算对循环泵叶轮和蜗壳进行了优化设计,分别以水力性能、叶片表面载荷、压力脉动强度、径向力脉动幅值这四个指标作为水力模型最优方案的判断标准,通过对比不同方案的计算结果,得到最优方案B50S0和C100S0。从水力优化设计过程中得出几点结论：1)叶片流线安放角β是影响叶片载荷的关键参数,合理的流线安放角能有效地降低叶片上的载荷,改善叶轮流道内的流动状态,降低叶轮的振动水平。对于B50和C100叶轮研究对象而言,当流线安放角β为25°时,叶片表面的压力载荷和相对速度载荷均最小。2)压力脉动强度与蜗壳基圆直径和喉部面积的大小成反比；径向力脉动幅值与蜗壳基圆直径的大小成反比；较大的蜗壳基圆直径和适中的喉部面积能有效地降低循环泵的压力脉动强度和径向力脉动幅值,进而降低振动。对于B50和C100循环泵而言,当蜗壳基圆直径D3分别为1.25D2和1.3D2时,具有较好的水力性能、较低的压力脉动强度和较小的径向力脉动幅值。3)首次提出了压力脉动强度与蜗壳基圆直径、喉部面积呈二次多项式的函数关系,随着蜗壳基圆直径、喉部面积的变大,压力脉动幅值逐渐变小,并最终趋近于一个极小值；径向力脉动幅值与蜗壳基圆直径呈二次多项式函数关系,随着蜗壳基圆直径的逐渐变大,径向力脉动幅值逐渐趋近于一个极小值。 4.对B50SO和C100S0方案进行了结构设计和样机试制,同时,为了降低泄露损失,创新设计了新型双道口环密封结构,以B50S0循环泵为研究对象,水力性能试验表明：与单道口环密封结构相比,双道口环密封结构的泵效率提升了6%。 5.首次在背景噪声小于16dB的半消音室和固有频率小于10Hz的振动试验平台上,根据ISO9906、ISO20361和ISO10816测试标准,采用麦克风传感器、压力传感器和振动加速度传感器分别对B50S0模型和C100SO模型进行了水力性能及振动噪声试验,试验结果表明：B50S0模型和C100SO模型达到了设计要求。 6.为了深入研究循环泵振动噪声特性,以B50SO模型为研究对象,测量了不同流量和转速下的振动噪声信号,采用1/3倍频程滤波法对振动噪声信号进行提取,分析了振动噪声与流量、转速及压力脉动之间的关系,发现了由流动分离引起的低频噪声主要存在于非设计工况下；噪声水平、压力脉动水平及结构振动水平与转速呈线性函数关系。研究发现：1)整个声压频域范围内,噪声水平从低频段到高频段呈先升高,后下降的趋势。2)非设计工况下的噪声水平、振动水平及压力脉动水平高于设计工况。3)由电机转子和定子的电磁感应所激励的高频振动主要存在于电机和电机座上。4)结构振动水平从大到小的排序依次为电机、法兰、电机座和泵体：靠近蜗舌区域和蜗壳出口扩散段处的振动水平高于泵体其它区域；法兰轴向上的振动小于径向振动。 7.优化后的B50SO和C100S0水力模型已用于格兰富相关产品(TPE3),效率分别超过欧洲最高可实现效率目标的5%和1%,振动和噪声水平(B50SO为1.05mm/s和65dB(A),C100SO为0.77mm/s和59dB(A))分别低于产品设计要求规定的1.8mm/s和68dB(A)。
[Abstract]:This paper is supported by the National Outstanding Youth Science Foundation of China (50825902). Circulating pump is one of the most widely used centrifugal pumps, mainly used in HVAC and domestic hot water circulation systems. At present, circulating pumps are mainly low in efficiency and high in vibration and noise level. With the introduction of new energy efficiency regulations and users' vibration noise, On the basis of the traditional centrifugal pump, how to improve the hydraulic efficiency and reduce the vibration and noise level of circulating pump by optimizing the geometric parameters on the basis of the traditional centrifugal pump design method has become an important research topic. This paper uses the method of theoretical analysis, numerical calculation and test verification to improve the hydraulic performance of the circulating pump. The characteristics of vibration and noise are studied in order to establish a set of hydraulic design method for high efficiency low vibration circulating pump based on CFD. The main work and creative achievements of this paper are as follows:
1. on the basis of the traditional centrifugal pump design method, on the premise of ensuring the flow and lift, the design speed is optimized, the design is more efficient than the speed in 40~70, and the key hydraulic parts impeller and volute of the circulating pump are optimized by the orthogonal test. The theory analysis and numerical calculation method is used to the circulating pump. The results show that the pump efficiency of the optimized B50 and C100 circulating pumps is 82.3% and 81.1% respectively, which satisfies the requirements of the design energy efficiency index and exceeds the maximum efficiency index of the centrifugal pump defined by the European standard. At the same time, the high speed, reducing the outer diameter of the impeller, makes the circulation pump as a whole. The structure is more compact, thus reducing the manufacturing cost.
2. improved the mathematical model of the hydraulic loss of the spiral case of the circulating pump, considering the hydraulic loss in the transition section between the impeller and the spiral case and the diffusion loss in the spiral case, predicting the overall hydraulic performance of the circulating pump and guiding the hydraulic optimal design of the spiral case. The experiment shows that the hydraulic loss of the volute can predict the hydraulic loss in the circulating pump more accurately. Loss, the calculation loss error is controlled within 5%.
3. the optimum design of the impeller and volute of the circulating pump is carried out with the orthogonal test and numerical calculation. The four indexes of the hydraulic model, the blade surface load, the pressure pulsation intensity and the radial force pulsation amplitude are considered as the criterion for the optimal scheme of the hydraulic model, and the optimal scheme B50S0 and C100S0. are obtained by comparing the calculation results of different schemes. Several conclusions are drawn from the hydraulic optimization design process: 1) the angle beta of the blade streamline is the key parameter affecting the blade load. The reasonable discharge angle of the streamline can effectively reduce the load on the blade, improve the flow state in the impeller flow channel, and reduce the vibration level of the impeller. For the research object of B50 and C100 impeller, when the streamline placement angle is concerned, When the beta is 25 degrees, the pressure load and relative velocity load on the blade surface are least.2). The pressure fluctuation strength is inversely proportional to the diameter of the volute base circle and the size of the throat area. The amplitude of the radial force pulsation is inversely proportional to the size of the base circle of the volute. The larger base circle diameter of the volute and the moderate throat area can effectively reduce the pressure of the circulating pump. For B50 and C100 circulating pumps, when the base circle diameter D3 of the worm shell is 1.25D2 and 1.3D2, with better hydraulic performance, lower pressure pulsation strength and smaller radial force pulsating amplitude.3), the pressure pulsation strength and the base circle diameter of the volute are first proposed for the first time, and the area of the throat is present. The function relation of the two order polynomial, with the diameter of the base circle of the volute, the area of the larynx becomes larger, the amplitude of the pressure pulsation gradually becomes smaller and eventually approaching to a minimum. The amplitude of the radial force pulsation has two polynomial functions with the base circle diameter of the volute, and the amplitude of the radial force pulsation gradually becomes closer to the one with the diameter of the worm shell base circle becoming larger. A minimum.
4. the structure design and prototype test of B50SO and C100S0 are carried out. At the same time, in order to reduce the leakage loss, a new type of double mouth ring seal structure is designed, and the B50S0 cycle pump is the research object. The hydraulic performance test shows that the pump efficiency of the double port ring seal structure is improved by 6%. compared with the single port ring seal structure.
5. for the first time, on the vibration test platform with the background noise less than 16dB and the natural frequency less than 10Hz, according to the ISO9906, ISO20361 and ISO10816 testing standards, the hydraulic performance and vibration noise test of the B50S0 model and the C100SO model are carried out by the microphone sensor, pressure sensor and vibration acceleration sensor respectively. The results show that the B50S0 model and the C100SO model meet the design requirements.
6. in order to study the vibration and noise characteristics of circulating pump, the B50SO model is taken as the research object. The vibration and noise signals of different flow and speed are measured. The 1/3 frequency multiplier filter is used to extract the vibration and noise signals, and the relationship between the vibration noise and the flow rate, the speed and the pressure pulse is analyzed, and the low flow separation is found. Frequency noise mainly exists in non design conditions; noise level, pressure fluctuation level and structure vibration level and speed are linear function relationship. The research shows: 1) the noise level rises from low frequency to high frequency Duan Chengxian, and then decreases after the whole sound pressure frequency range. The noise level, the vibration level and pressure in the non design conditions are 1. The pulsation level is higher than the design condition.3) the high frequency vibration excited by the electromagnetic induction of the rotor and stator of the motor mainly exists in the motor and the motor seat.4). The order of the vibration level from large to small is the motor, flange, motor base and pump body: the vibration level near the worm tongue area and the outlet of the worm shell is higher than the other areas of the pump body. The vibration of the flange in the axial direction is less than that of the radial vibration.
The 7. optimized B50SO and C100S0 hydraulic models have been used for the green rich related products (TPE3), and the efficiency exceeds 5% and 1% of the highest achieved efficiency targets in Europe. The level of vibration and noise (B50SO for 1.05mm/s and 65dB (A), C100SO for 0.77mm/s and 59dB (A)) are lower than those stipulated in product design requirements respectively.
【学位授予单位】：江苏大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TH311

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