共查询到19条相似文献,搜索用时 140 毫秒
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低扬程贯流泵装置模型试验研究 总被引:5,自引:0,他引:5
以模型试验为主配合CFD分析,较全面地研究了后置灯泡模型贯流泵装置的水动力性能。通过对扩散导叶、灯泡体和进水流道尺寸的优化,获得了性能优良的模型贯流泵装置结构,使得模型贯流泵装置在净扬程为3.0m,模型流量小于340L/s(D=0.3m,n=1450r/min)的范围内获得76%以上的装置效率。采用商用CFD软件对贯流泵进行数值分析,发现在采用传统方法设计的扩散导叶内普遍存在大范围的脱流,这是影响贯流泵装置效率的主要因素,为进一步优化贯流泵装置找到了突破口。 相似文献
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《流体机械》2017,(10):58-63
以混流式核主泵水力模型为研究对象,基于三维不可压缩流体的N-S方程和RNG k-ε湍流模型,采用流体计算软件ANSYS-Fluent对不同工况下的混流式核主泵水力模型的三维湍流流场进行数值模拟。通过分析不同特征面上的流动状态,构建该泵内的典型时均流谱,为性能优化及内部流动控制提供参考。计算结果表明:高涡量区域主要分布在固体壁面、径向导叶流道以及球型压水室内出液管附近;靠近出液管附近存在旋涡,导致流动损失增加,但随着流量减小,此处的流动情况趋于稳定,旋涡减弱甚至消失;靠近球型压水室出液管段的旋涡及其相近的径向导叶流道内的复杂流动情况与球型压水室出液管的位置有一定关系,因此减小出液管附近的流动损失,对实现混流式核主泵流动控制具有重要意义。 相似文献
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基于RNG k-ε湍流模型和雷诺时均N-S方程,运用CFD技术对采用肘形流道的某泵站轴流泵装置分别在叶片角度为-2°,0°和+2°时进行三维流动数值模拟,以探究不同叶片角度下肘形流道的流动特性,以及肘形流道与叶片角度对轴流泵装置性能的影响,并对肘形流道内进行了非定常计算。通过计算得到叶片角度对肘形流道内水流流动状态会产生影响,叶片角度的不同导致肘形流道内的流态也会不同,不同叶片角度下叶轮进口的流速均匀度也会产生差异。在不同叶片角度下,轴流泵装置的肘形进水流道内压力脉动同样会产生很大的差异,压力脉动的差异会对机组的振动产生影响,通过对比叶片角度对采用肘形流道的轴流泵装置特性的影响,可以为工程中轴流泵装置叶片角度的调节提供一定的参考。 相似文献
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斜轴伸泵装置水动力数值计算与模型试验 总被引:2,自引:0,他引:2
为研究斜轴伸泵装置的水动力特性,基于ANSYS CFX软件采用RNG k-ε湍流模型和可伸缩壁面函数对泵装置进行三维粘性湍流定常数值计算,计算区域包括叶轮、导叶和进、出水流道,共计算包括设计工况在内的9个工况点。计算结果揭示出该泵装置的内部流动特性,分析在叶轮旋转条件下斜15°进水流道出口断面的水力性能及其对叶轮进口断面相对高度位置的影响和叶轮受水流作用力的分布规律,并探讨水力矩的变化规律及翼型附近的相对流速分布,给出参考的叶轮名义安装高度取值范围(0.7~0.9)D。通过数值计算预测了模型泵装置的水力性能并与物理模型试验结果进行对比,预测的效率值和试验值最大绝对误差为5.01%,最优工况与设计工况时扬程的相对误差、效率的绝对误差均在3.5%以内。 相似文献
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后置灯泡贯流泵三维紊流计算 总被引:2,自引:0,他引:2
通过计算流体力学(Computational fluid dynamics, CFD)方法研究某一后置灯泡贯流泵内部的三维流场,采用RNG k-ε紊流模型和SIMPLE算法对泵叶轮、导叶和进出水流道内的流场进行数值模拟.分析最优工况下装置纵断面的流速和压力分布以及叶轮出口、导叶出口和灯泡体尾部的流速分布情况.着重研究小流量工况、最优工况和大流量工况等不同工况下叶片压力面、吸力面的静压分布以及各断面翼型附近的相对流速分布.同时还计算贯流泵装置各种构件的水力损失,发现导叶体和灯泡体段在水力损失中所占的比重较大.将数模计算结果与模型试验的泵装置性能数据进行对比,结果表明数模计算结果跟试验数据在高效区附近吻合较好,在小流量和大流量工况下存在偏差.采用CFD方法对灯泡贯流泵装置内部流场进行数值模拟可以为泵装置进一步设计优化提供依据. 相似文献
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《水泵技术》2017,(4)
炉水循环泵是机泵一体的高温高压无轴封泵,运用ANSYS-CFX软件对365WLB-965型炉水循环泵样机的内部流场进行数值模拟和试验验证。结果表明,在常温常压工况下,数值模拟与真机试验的扬程及效率变化趋势大致相同,扬程基本相符,模拟效率高于真机试验效率。在高温高压小流量工况下,叶轮内部存在少量旋涡,导叶内部旋涡较多;随着流量的增大,流动更加稳定,叶轮流域速度分布更加均匀,导叶内部旋涡越来越少;在1.2Q流量时,流动最为稳定;流量继续变大时,旋涡重新出现,但相对稳定;泵体内部流动紊乱,旋涡较多,局部存在低压区;球体截面直径减小的过程中,旋涡越来越多,旋涡随流量的增大逐渐减少,流动速度随流量的增大逐渐增大。炉水循环泵应避免在小流量区运行,可对其导叶进行优化设计来提高炉水循环泵样机额定工况下的性能。 相似文献
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利用CFD软件Fluent对多级导叶式清水离心泵的内部流场进行了数值模拟,得出了叶轮及导叶内部流道的速度和压力分布规律,并发现了叶轮进口回流,出口的二次流动特征等叶轮内部流动的细节,导叶出口区产生了一个低压区等流动特征。然后根据自编计算软件利用计算得到的速度场数据计算出泵的扬程、功率、效率和流量之间的关系曲线,并与试验数据进行了比较。结果表明:在设计工况附近,预测值与试验值吻合较好,在其它工况点,特别是小流量工况点,误差较大。 相似文献
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Numerical simulation and analysis of flow characteristics in the front chamber of a centrifugal pump
Yang Wu Xiaoping Chen Hua-Shu Dou Lulu Zheng Zuchao Zhu Baoling Cui Boo Cheong Khoo 《Journal of Mechanical Science and Technology》2017,31(11):5131-5140
We performed numerical simulations to study the flow characteristic in a centrifugal pump based on the RANS equations and the RNG k-ε turbulent model. The flow field, including the front and back pump chambers, the impeller wear-ring, the impeller passage, the volute casing, the inlet section and outlet section was calculated to obtain accurate numerical results of fluid flow in a centrifugal pump. The flow characteristic was studied from the internal flow structure in pump chambers, the radial velocity at impeller outlet as well as the pressure inside of the pump, the circumferential velocity and the radial velocity in front pump chamber. The variation of flow parameters in internal flow versus flow rate in the centrifugal pump was analyzed. The results show that the overall performance of the pump is in good agreement with the experimental data. The simulation results show that the distribution of flow field in the front pump chamber is axial asymmetry. The energy dissipation at the impeller outlet is larger than other areas. The distribution of the circumferential velocity and that of radial velocity are similar along the axial direction in the front pump chamber, but the distribution of flow is different along the circumferential and the radial directions. It was also found that the vorticity is large at the impeller inlet compared with other areas. 相似文献
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Qiaorui Si Patrick Dupont Annie-Claude Bayeul-Lainé Antoine Dazin Olivier Roussette Gérard Bois 《Journal of Mechanical Science and Technology》2016,30(2):549-556
The overall performance of a vane-island type diffuser of a centrifugal pump model was obtained by means of directional probe traverses. These measurements were performed in an air model of a real hydraulic pump for five volume flow rates. Directional probe traverses are performed with a classical three-hole probe to cover most of the complete inlet section of the diffuser from hub to shroud and from pressure to suction side. Existing Particle image velocimetry (PIV) measurement results are also used to compare probe measurement results between the inlet and outlet throats of vane island diffuser at mid-span. Some assistance from already existing unsteady calculation, including leakage effects, is used to evaluate the numerical approach capability and to correctly define the mean initial conditions at impeller’s outlet section. Pressure recovery and the measured total pressure loss levels inside this particular vane diffuser geometry are then calculated. Detailed analysis of the flow structure at the inlet section of the vane island diffuser is presented to focus on pressure evolution inside the entire diffuser section for different flow rates. The combined effects of incidence angle and blockage distributions along hub to shroud direction are found to play an important role on loss distribution in such a diffuser. 相似文献
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应用滑移网格技术分析多级离心泵的三维瞬态流动 总被引:2,自引:0,他引:2
运用滑移网格技术、三维非稳态Navier-Stokes方程和标准的k-e湍流模型对工业中常用的D型多级节段式离心泵进行了全三维瞬态流场的数值模拟,分析泵内叶轮与导叶间的动静干扰问题.滑移网格设置在多级离心泵叶轮出口与固定导叶入口之间的交互界面,对每个时间步求解流动方程.对任一个叶轮旋转周期内,分析叶轮径向力、静压等参数出现脉动信号频率与动、静叶片数的关系;分析静、动叶片间静压值沿周向的变化规律.该三维非稳态模拟结果可为多级离心泵的水力优化设计提供依据. 相似文献
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《风机技术》2021,(2)
In order to investigate the complex flow characteristics inside an unshrouded centrifugal impeller with splitter blades at off-design conditions, and analyze its influence on pump operation stability, a numerical simulation study was carried on using the curvature-corrected SST-CC turbulence model; the head and efficiency accorded with experimental results. The pressure fluctuation, unsteady radial force and velocity were analyzed quantitatively and the numerical results indicate this: the peak to peak value of pressure fluctuation in the impeller channel gradually increases in the flow direction and at 0.49 Qn, the slope of peak to peak value to normalized impeller channel behind the splitter blade is 8.57 times greater than that before the splitter blade. The greater the flow rate deviates from the design condition, the larger the peak to peak value of the pressure fluctuation and radial force; in particular at 0.27 Qn, the maximum radial force is 194.29% greater than that of the design condition. When the operating flow rate is smaller than0.83 Qn, the stall occurs and the stall vortex could block the impeller discharge; as the flow rate decreases further, the pressure amplitude at rotational frequency gradually increases in the impeller channel and the prevailing frequency changes from the blade passage frequency(BPF) to the rotating stall frequency in the diffuser. The tip leakage vortex(TLV) is generated in the tip region and rotated move downstream in the impeller flow channel, and the backflows appear on the blade suction side and in the tip and the tongue regions; the smaller the flow rate, the more serious the TLV and backflow phenomenon. The rotating stall causes uneven flow in the impeller channel, increasing the pressure fluctuation and the radial force, and resulting in an imbalance of the impeller rotation. 相似文献
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考虑到离心压缩机末级各通流元件之间的相互影响,将末级叶轮、无叶扩压器和排气蜗壳组合一起对扩压器出口直径与叶轮直径的比值D4/D2进行研究,通过对不同D4/D2条件下的整级模型进行数值模拟,研究扩压器流道长短对整级性能的影响,对离心压缩机末级流场及D4/D2值变化与离心压缩机整级性能的变化关系进行了详细的对比分析.研究结果表明,D4/D2值的变化对末级整级性能有较大的影响,并存在一个使级效率为最大值的最佳D4/D2值,D4/D2过大或过小都将使整级效率下降. 相似文献
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Junghyun Lee Mohammad Moshfeghi Nahmkeon Hur In Sik Yoon 《Journal of Mechanical Science and Technology》2016,30(9):3993-4000
Flow recirculation is an unpleasant and even hazardous phenomenon that can cause mechanical damage in turbomachinery and has to be prevented during their operations. We numerically studied the effects of return channel blade curvature on reducing the recirculation of flow inside the return channel vanes of a multi-stage centrifugal pump. Computational fluid dynamics (CFD) analyses were performed for a wide range of volumetric flow rates. The standard k-ε turbulence model was adopted as the turbulence model, and the impeller rotation simulated employing the Multiple reference frames (MRF) method. First, a baseline model together with five different modified geometries for return channel was studied and compared using a two-stage pump framework. The results reveal that decreasing the curvature of the return channel blade makes smooth streamlines and eliminates the flow recirculation inside the return channels. As the second part, two return channels with the highest pump performance were selected to be used in the simulation of a multistage pump. The simulations of the multi-stage pump show that the flow inside the baseline return channel includes considerable areas of flow recirculation, while the modified return channels again have attached flow stream. It is concluded that the return channels with the smooth curvatures and outlet blade angles above 90° remove the flow recirculation inside the return channels, resulting in higher pump efficiencies. 相似文献