Optimal Design of High-Speed Partial Flow Pumps using Orthogonal Tests and Numerical Simulations

To investigate the influence of structural parameters on the performances and internal flow characteristics of partial flow pumps at a low specific speed of 10000 rpm,special attention was paid to the first and second stage impeller guide vanes.Moreover,the impeller blade outlet width,impeller inlet diameter,blade inclination angle,and number of blades were considered for orthogonal tests.Accordingly,nine groups of design solutions were formed,and then used as a basis for the execution of numerical simulations(CFD)aimed at obtaining the efficiency values and heads for each design solution group.The influence of impeller geometric parameters on the efficiency and head was explored,and the“weight”of each factor was obtained via a range analysis.Optimal structural parameters were finally chosen on the basis of the numerical simulation results,and the performances of the optimized model were verified accordingly(yet by means of CFD).Evidence is provided that the increase in the efficiency and head of the optimized model was 12.11%and 23.5 m,respectively,compared with those of the original model.

Optimization of a Centrifugal Pump Used as a Turbine Impeller By Means of an Orthogonal Test Approach

A prototype centrifugal pump with a specific speed of 110 is used to investigate and optimize the performances of a turbine for power generation.Particular attention is given to the design of the internal impeller.The internal flow field is simulated in the framework of a commercial computational fluid dynamics software(ANSYS).Four geometrical parameters of the impeller are considered,i.e.,the inlet diameter,the inlet width,the blade number,and the blade angle.The optimization is carried out on the basis of a three-level approach relying on an orthogonal test method.The results of the numerical simulations show good agreement with the experimental tests under different flow conditions.In accordance with the L9(34)design table,the head and efficiency under the rated flow rate of the nine designed schemes are calculated and processed with the method of range analysis to obtain an optimized model.

Modelling Design and Test of Steam Centrifugal Compressor

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centrifugal用热控装置设计

目的评估飞行器产品在飞行过程对热–离心综合环境的适应性,研制一套热–离心综合环境试验用热控装置。方法从热–离心试验需求出发,完成综合试验系统总体研制目标及系统方案设计。针对高g值离心环境(离心加速度值≥90g)下的热载荷加载需求,开展基于热传导的热载荷加载方法研究,并完成适用于高g值环境的热控装置硬件布局优化设计。提出基于分段包络思想的产品响应温度梯度分布效应模拟方法及实现,减少过试验考核。结果利用该热控装置完成了热–离心综合环境功能验证试验,设置最大加速度为92g,保载时间为3 min,最高加热温度为150℃,最大温升速率为3℃/min,3温区控制,升温过程中,温度误差优于±1.5℃。结论该热–离心综合环境试验用热控装置可用于飞行器产品热–离心综合环境试验的考核。

Discrete Optimization on Unsteady Pressure Fluctuation of a Centrifugal Pump Using ANN and Modified GA

Pressure fluctuation due to rotor-stator interaction in turbomachinery is unavoidable,inducing strong vibration in the equipment and shortening its lifecycle.The investigation of optimization methods for an industrial centrifugal pump was carried out to reduce the intensity of pressure fluctuation to extend the lifecycle of these devices.Considering the time-consuming transient simulation of unsteady pressure,a novel optimization strategy was proposed by discretizing design variables and genetic algorithm.Four highly related design parameters were chosen,and 40 transient sample cases were generated and simulated using an automatic program.70%of them were used for training the surrogate model,and the others were for verifying the accuracy of the surrogate model.Furthermore,a modified discrete genetic algorithm(MDGA)was proposed to reduce the optimization cost owing to transient numerical simulation.For the benchmark test,the proposed MDGA showed a great advantage over the original genetic algorithm regarding searching speed and effectively dealt with the discrete variables by dramatically increasing the convergence rate.After optimization,the performance and stability of the inline pump were improved.The efficiency increased by more than 2.2%,and the pressure fluctuation intensity decreased by more than 20%under design condition.This research proposed an optimization method for reducing discrete transient characteristics in centrifugal pumps.

Performance Prediction of an Optimized Centrifugal Pump with High Efficiency

The main structural parameters of the IR100-80-100A type chemical centrifugal pump have been optimized by means of an orthogonal test approach.The centrifugal pump has been modeled using the CFturbo software,and 16 sets of orthogonal-test schemes have been defined on the basis of 4 parameters,namely,the blade number,blade outlet angle,impeller outlet diameter,and impeller outlet width.Such analysis has been used to determine the influence of each index parameter on the pump working efficiency and identify a set of optimal combinations of such parameters.The internalflowfield in the centrifugal pump has been simulated by using the PumLinx software.These numerical results have shown that,compared with the prototype pump,the outlet pressure and shaft power of the optimized pump can be significantly reduced,and the pump working efficiency can be improved by 5.59%.In the present study,some arguments are also provided to demonstrate that,with respect to other optimization methods,the orthogonal test approach is more convenient,and requires less test times.

基于高维混合模型的离心泵叶轮子午面优化设计

为提高离心泵在设计工况下的运行效率和扬程,提出一种基于高维混合模型的离心泵叶轮优化设计方法.选取一台比转数为157的单级离心泵作为研究对象,通过CFturbo软件对优化变量进行参数化,然后结合数值模拟获得高维混合模型的训练集.在此基础上采用获取的训练集通过MATLAB机器学习得出效率、扬程与优化参数之间关于支持向量回归的高维模型,并采用遗传算法寻优.在设计工况下,所拟合的高维混合模型预测的效率和扬程值比原模型分别高1.5%和3.2 m,数值模拟验证优化方案的效率和扬程分别比原模型高0.9%和2.1 m.算例研究表明,将高维混合模型应用于离心泵叶轮的优化设计中可以实现快速寻优并提高离心泵水力性能.

基于Kriging的多阶段加点策略及离心叶轮汽蚀优化

为了实现燃油离心泵汽蚀特性智能优化设计,提出一种基于Kriging的多阶段主动学习加点策略。重点是建立3个阶段的加点策略,并明确各阶段加点策略的切换判据。基于一维函数、多维函数等测试函数,与单加点策略对比以验证多阶段主动学习加点策略的有效性。进而,以某型燃油离心泵为例,完成所提出加点策略在其汽蚀特性的优化应用。测试函数算例结果表明:多阶段主动学习加点策略达到相同精度所需时间稍长于单MSE策略,优于单EI策略与单CV策略;但相比单MSE策略,全局最优解局部精度更高。离心泵汽蚀特性优化结果表明:优化泵进口处压力损失降低且进口处回流、旋涡等局部流动减弱,蜗壳内压力梯度增大且其出口处旋涡流动减弱;优化泵的汽蚀系数提高30.83%,汽蚀余量下降9.14%,汽蚀比转数下降7.17%,泵内气体含量下降17.27%,所提出的方法有效地提高了离心泵的抗汽蚀性能。

基于神经网络与遗传算法的离心泵汽蚀性能优化设计

为了研究离心泵发生汽蚀过程时其内部流动规律和对其汽蚀性能的优化设计,在结合传统优化方法的基础上,提出神经网络与遗传算法结合的智能优化方法。通过Plackett-Burman试验设计从离心泵的叶轮进出口直径、进出口安放角、叶片数、叶片包角等7个设计参数中筛选出显著影响的3个优化设计变量。叶片出口宽度、叶片包角和叶轮出口直径3个优化设计变量,其影响汽蚀性能的显著性由大到小。运用拉丁超立方抽样方法抽取30组设计方案,分别进行数值模拟计算,得出相应的汽蚀余量值。建立神经网络模型,结合遗传算法在规定范围内进行寻优,得到最优设计变量组合及最优汽蚀余量值。取优化后的参数进行数值模拟计算,优化后的离心泵在相同工况下汽蚀余量降低了43.1%,说明优化后的离心泵抗汽蚀性能显著提高。

大型离心泵空化性能与驼峰不稳定特性相关性分析

空化现象和驼峰不稳定特性是影响离心泵机组安全稳定运行的主要因素。基于某大型离心泵两种叶轮方案的数值计算和模型试验结果对空化性能和驼峰不稳定特性进行比较分析,以探究两者之间的相关性,同时,分析了驼峰产生机理及空化性能在其中发挥的作用。数值结果表明,由于空化特性的影响,在数值计算结果中离心泵H-Q性能曲线上出现了驼峰不稳定现象。此外,在小流量区域叶片表面压力分布均匀,最低压力分布合理的空化性能优异叶轮,其驼峰不稳定特性得到显著改善。模型试验结果表明,在泵站正常运行条件下,提升小流量区域装置空化系数与初生空化系数的比值,在叶轮空化性能提升时驼峰裕度增加。研究结果表明,离心泵空化性能与驼峰不稳定特性存在正向相关关系,小流量区域叶轮空化性能提升后可以降低空化现象的发生程度,叶轮流道内部流态改善,整体水力效率提高,相应的驼峰不稳定特性得到提升。研究成果将对大型离心泵机组安全稳定运行提供设计参考。

Numerical Simulation and Experimental Research on the Influence of Solid-phase Characteristics on Centrifugal Pump Performance

The law governing the movement of particles in the centrifugal pump channel is complicated; thus, it is difficult to examine the solid-liquid two-phase turbulent flow in the pump. Consequently, the solid-liquid two-phase pump is designed based only on the unary theory. However, the obvious variety of centrifugal-pump internal flow appears because of the existence of solid phase, thus changing pump performance. Therefore, it is necessary to establish the flow characteristics of the solid-liquid two-phase pump. In the current paper, two-phase numerical simulation and centrifugal pump performance tests are carried out using different solid-particle diameters and two-phase mixture concentration conditions. Inner flow features are revealed by comparing the simulated and experimental results. The comparing results indicate that the influence of the solid-phase characteristics on centrifugal-pump performance is small when the flow rate is low, specifically when it is less than 2 m3/h. The maximum efficiency declines, and the best efficiency point tends toward the low flow-rate direction along with increasing solid-particle diameter and volume fraction, leading to reduced pump steady efficient range. The variation tendency of the pump head is basically consistent with that of the efficiency. The efficiency and head values of the two-phase mixture transportation are even larger than those of pure-water transportation under smaller particle diameter and volume fraction conditions at the low-flow-rate region. The change of the particle volume fraction has a greater effect on the pump performance than the change in the particle diameter. The experimental values are totally smaller than the simulated values. This research provides the theoretical foundation for the optimal design of centrifugal pump.

储液-桩基LNG储罐地震离心模型试验设计方法

LNG储罐作为国家重要的战略能源储备工程,正快速向超高容量、超大直径、半地下化趋势发展,并对抗震安全性要求极高。针对离心模型试验规格尺寸限制,提出一种以储罐自振周期、晃动周期和抗弯刚度为主要控制参数的LNG储罐试验设计方法,并以原型为27万m3的大型储罐开展了相应动力离心试验,验证了设计方法的合理性并分析了其地震响应。结果表明:试验得到的自振周期与规范计算值较为接近,误差为5.6%,验证了该试验设计方法的可靠性;储液晃动频率与荷载幅值变化关系不大,主要与储罐形状、液面高度有关,储液晃动波高与荷载幅值呈现明显正相关;桩基础可以提升LNG储罐的安全性,相同荷载激励下,有桩储罐比无桩储罐晃动波高减小约8.2%。

基于Moldex 3D与正交试验的离心泵泵头注塑工艺优化

以商用离心泵泵头为研究对象,运用Moldex3D模流分析软件对其注塑成型过程进行了模拟。根据产品的结构特点设置了三种浇口方案,通过对注塑过程的模拟分析选出最佳方案来获得模具设计思路并预测制品成型后可能存在的质量问题。结果表明,平衡进浇方案的制品具有最好的综合性能,制品的翘曲变形量为1.588 mm,体积收缩率为2.444%。确认最佳浇口方案后,将充填时间(A)、保压时间(B)、冷却时间(C)和模具温度(D)作为实验因素,采用田口法构建五因素四水平的正交试验来获得最佳工艺参数,并使用极差和方差分析对结果进行置信度检测。以翘曲总位移结果为主要权重对象,通过极差分析确定了成型参数的最优组合为A_(1)B_(1)C_(1)D_(1),方差分析则验证了极差分析的结果置信度高于99%。相较于初始方案,制品的翘曲变形量从1.588 mm降低至1.214 mm,降低了23.6%;冷却时间降低至10 s,降低了40%。得知模流分析技术的使用让产品的质量和生产效率都得到了明显的优化,为预测塑件性能、降低生产成本、提高生产效率提供了一种可行的方式。

特大流量潜水贯流泵叶轮水力设计优化研究

针对Q=100 m³/s的特大流量潜水贯流泵装置,对叶轮叶片及导叶进行水力设计,基于正交试验方法进行优化,对最优泵装置方案进行CFD计算,探究机组外特性,并对导叶出口边齐平与不齐平的两种导叶安放型式机组水力性能参数进行了对比分析。研究结果表明:叶轮轮毂比为0.4,叶片数为4,导叶数为6时,泵装置的效率最高,泵装置的最高效率为80.52%;1.0Qd工况下泵装置扬程为2.73 m,效率为74.68%;0.87Qd工况下泵装置扬程为4.50 m,效率为80.14%;1.12Qd工况下泵装置扬程为0.45 m,效率为23.77%;从扬程、效率、导叶段水力损失等参数,得出不齐平的导叶出水边安放型式机组水力性能更优。针对叶轮和导叶的造型方法及正交试验与CFD计算组合的优化方法均提高了水力优化工作效率,适于推广应用,研究成果对低扬程特大流量水泵开展的计算分析工作也为潜水贯流泵大型化发展提供了一定的水力性能参考。

基于正交试验的单级双吸离心泵多目标优化设计

单级双吸离心泵由于运行平稳、噪声小、故障率低、易于维护等优点,已成为水利工程中最普遍、最通用的设备。本文以型号为950SY240-HY的单级双吸离心泵为研究对象,通过模型试验与数值模拟,以扬程和效率为目标函数进行多目标优化,在原型泵的基础上对叶片进、出口安放角、叶片包角、叶轮出口直径、出口宽度及叶片数这六个叶轮关键参数设计了L^(18)(3^(5)×2^(1))正交试验。通过极差分析,明确了各因素对单级双吸离心泵水力性能的影响程度,发现叶轮出口宽度、叶片出口安放角和叶片数对单级双吸泵扬程与效率的影响最大。相比于原始方案,正交试验最终确定的单级双吸离心泵设计方案,各工况点下扬程与效率有显著提高,叶轮内流态得到改善,流动损失减小,水力性能提高,额定工况下效率提高了4.1%,符合优化的目标。

基于Moldflow的排水泵过滤网注塑工艺优化与模具设计

利用Moldflow对塑料排水泵过滤网的注塑成型过程进行仿真,通过对其结构分析制定了合理的浇口位置和冷却水路。利用三因素三水平正交试验,研究了熔体温度(A)、充填压力(B)和开模时间(C)对于塑件翘曲变形的影响,得出较优的工艺参数组合为A_(1)B_(3)C_(3),即熔体温度220℃,充填压力80%,开模时间6 s,此时塑件的最大翘曲变形量为0.632 8 mm,与优化前相比降低了10.37%。最后依据Moldflow的分析结果,利用UG软件对注塑模具的结构进行了设计,根据塑件卡扣的结构特点,型腔采用整体式结构,型芯设计为组合式(主型芯+滑块)结构,并采用三组“斜导柱+滑块”式侧向抽芯机构解决脱模问题。为实现顺序脱模,借助尼龙塞以增加定模板与动模板之间的开模阻力,设计了内置式“小拉杆+拉杆套”结构的定距分型机构;考虑到塑件形状和模具结构与成本,设计了沿塑件侧壁轮廓排布的圆推杆脱模机构;为避免气纹、气穴等缺陷的形成,在型腔处设计了排气槽结构。该模具结构设计较为合理,可为其他结构相似塑件的模具设计提供有益参考和指导。

清水离心泵再制造叶轮优化设计方法研究

针对广泛存在的数量众多、效率低下、结构陈旧、面临淘汰的离心水泵,探寻其叶轮再制造优化设计有效途径。基于ANSYS workbench联合CFturbo,提出一种叶轮参数化仿真建模和叶轮优化设计的方法,借助ANSYS workbench响应面优化模块,以扬程不小于原始泵为约束条件,效率为目标函数,采用拉丁超立方抽样方法设计41组实验,建立响应面代理模型,并采用MOGA算法对低比转速离心泵进行寻优。研究结果表明,该方法应用于某一低比转速离心式水泵,在其扬程不变的条件下,效率提高了2.11%,对清水离心泵叶轮再制造优化设计、提高离心泵运行效率有一定的参考价值。

基于CFD的离心泵水力性能优化设计

针对传统离心泵在工作时水力性能较差的问题,采用计算流体动力学技术对IS80-50-250型清水泵蜗壳结构参数进行优化设计。选取蜗壳基圆直径、蜗壳进口宽度、蜗壳第八断面半径和隔舌安放角4个结构参数制定正交试验方案。采用Pumplinx软件对各组方案进行数值模拟,获得离心泵内部流场分布规律。模拟结果表明,相较于原型泵,在额定转速下优化泵的出口压力提高了3.27%,蒸汽质量分数降低了10.47%,进一步提升了离心泵的水力性能。为验证优化方案的准确性,搭建离心泵外特性试验测试台,得到了在不同工况下原型泵和优化泵的外特性曲线。试验结果表明,在额定工况下,离心泵扬程和效率分别提高了4.43%和4.44%,进一步验证了正交试验优化方案的准确性和可行性,为下一步高性能离心泵设计提供了技术依据。

用于催化裂化装置强制循环泵的三元导叶设计方法及性能分析研究

强制循环泵是催化裂化装置烟气热量回收系统中重要的水循环动力设备,蜗壳为半球形结构带导叶的LUV型泵是一种广泛应用的强制循环泵,其导叶结构对泵的性能有着至关重要的影响。本文针对强制循环泵二元导叶在不同叶高处的进口叶片安装角与水流角不匹配的问题,发展了采用后盖板和前盖板的叶片中弧线角度分布和叶片厚度分布来构建叶型的三元导叶叶片结构设计方法,并数值研究了导叶后盖板和前盖板处进出口叶片安装角对泵额定工况效率和内部流动特性的影响。结果表明:随着前后盖板叶片进出口安装角中一个变量的增大,额定流量点效率均先增大后减小;设计的三元导叶方案比二元导叶方案在额定工况下的效率提高了0.9%;后盖板附近的叶片安装角与水流角的匹配性对泵的效率起到了更加重要的作用;三元导叶方案在后盖板附近0.1叶高截面上进口水流角与叶片安装角的匹配关系得到改善,此截面上的旋涡区减少,导叶内的能量耗散减小。

超高比转速离心泵的高效设计

为研究叶轮结构参数对提升n_(s)在300~450间的超高比转速离心泵设计点效率的影响,以某超高比转速单级单吸立式离心泵为研究对象,选取叶轮出口宽度b_(2)、叶片进口安放角β_(1)、叶片出口安放角β_(2)和叶片包角φ为试验因素,建立L_(9)(4~3)正交试验方案,在0.9Q_(n)~1.1Q_(n)工况内对各方案模型进行数值计算,分析各因素对泵水力性能影响的主次顺序,进而得到叶轮结构尺寸的最佳参数组合。按照最佳尺寸优化叶轮,将优化后的泵外特性试验结果与原型进行了对比分析。结果表明:(1)高效设计时超高比转速离心泵叶轮结构参数对效率影响的主次顺序为φ→b_(2)→β_(2)→β_(1),影响水力性能的主要因素为φ,以便指导超高比转速离心泵的高效设计;(2)确定了高效设计时叶轮结构参数的最优水平组合;(3)优化后泵设计点效率较原型提高约4.2%,高效区扩宽至0.75Q_(n)~1.1Q_(n)工况,效率整体提升2.5%以上;(4) 0.75Q_(n)~1.2Q_(n)工况优化后泵轴功率与原型相比降低5.8%~15.8%,利于节能减排。