共查询到15条相似文献,搜索用时 46 毫秒
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叶轮偏心将会引起轴流泵叶轮顶部间隙沿周向不均匀,从而导致附加的流动激励和噪声.利用计算流体力学商业软件Fluent模拟不同偏心度和间隙比的轴流泵非定常流场,研究周向非均匀间隙对泵内压强脉动及叶轮激励力的影响.结果表明:壁面压强脉动强度并不是在最小间隙处达到最大,而是出现在偏离最小间隙处约30°~60°的方向,并随着间隙比增大,脉动强度最大值发生位置逐渐向最小间隙处靠拢;同时,偏心造成的非均匀叶顶间隙引起了轴频处的压强脉动,在间隙比为2.5%下偏心度从0%增加到60%,轴频处的压强脉动相对增量为661.54%;叶轮受到的径向激励力时均值与偏心度呈线性关系,其斜率与间隙比的平方根成正比. 相似文献
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针对叶片厚度分布对两级离心泵空化性能的影响,通过对第一级叶轮叶片的厚度分布进行优化,研究其对泵外特性、压力脉动以及流体激励力的影响。结果表明:采用线性厚度分布的对称叶片时,前缘厚度对空化性能的影响最大,叶片越薄,泵的抗空化能力越强;随着尾缘变厚,压力脉动幅值向叶轮进口方向偏移,且随着叶片厚度减小,压力脉动幅值相应减小。第一级叶轮流道内的压力脉动主频为干涉叶频,保留高幅低频的宽频特征,所受空间三向力的脉动主频为2倍叶频,轴向力较小,脉动幅值较低,径向力的主要信号成分是叶频和2倍叶频。 相似文献
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振动及空化是影响离心泵性能的重要因素。为了进一步优化流道,提高离心泵的性能,在保证离心泵其他参数不变的情况下,设计了3种不同叶片数叶轮。对3种离心泵进行全流道三维非定常湍流数值模拟,分析叶片数对离心泵性能的影响。结果显示:不同叶片数离心泵在两个监测点的压力脉动主频都是相对应的叶片通过频率,次频为叶片通过频率的倍频。叶片数的变化对隔舌处的压力脉动变化影响较大。随着叶片数的增加,离心泵的扬程逐渐增大,离心泵的效率变化比较复杂,当叶片数为5时,离心泵的效率最高。随着进口压力的不断降低,离心泵叶轮所受扭矩发生变化,在临界空化余量附近,泵扭矩发生陡降。 相似文献
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Jie Wang Yoichi Kinoue Norimasa Shiomi Toshiaki Setoguchi Kenji Kaneko Yingzi Jin 《热科学学报(英文版)》2008,17(4):356-360
Experimental investigations were conducted for the internal flow of the stator of the diagonal flow fan. Comer separation near the hub surface and the suction surface of the stator blade are focused on. At the design flow rate, the values of the axial velocity and the total pressure at stator outlet decrease near the suction surface at around the hub surface by the influence of the comer wall. At low flow rate of 80-90 % of the design flow rate, the comer separation between the suction surface and the hub surface can be found, which become widely spread at 80 % of the design flow rate. 相似文献
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以配套1000MW等级超超临界汽轮发电机组的22.5MW给水泵汽轮机为研究对象,介绍了该给水泵汽轮机转子功率高、推力大、转速范围广的特性及开发难点。通过对转子进行离散模化并利用传递矩阵法,分析研究了转子结构中各因素对其临界转速的影响及敏感性,并进一步分析、计算了对转子轴向推力的联带影响。论文最终通过对转子推力及动力学特性的协调性研究,得出了缓解转子轴向推力和临界转速互相矛盾的结果;证明单缸单流结构仍然能够适用于22.5MW等级给水泵汽轮机,并保证其安全、稳定、高效的运行。 相似文献
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JIANG Chenglong;YIN Zhao;ZHANG Hualiang;ZHOU Peijian;LIU Yu;CHENG Kun;XU Yujie;CHEN Haisheng 《热科学学报(英文版)》2024,33(6):2097-2116
Turbine generators play a pivotal role in efficiently converting gas internal energy into electrical energy,finding extensive applications in diverse green energy and power equipment.The adoption of a high-speed direct-drive structure eliminates mechanical losses associated with the reducer between the turbine and generator,enhancing system efficiency and compactness.However,this configuration introduces challenges in design and manufacturing.This article explores the various application scenarios of high-speed direct-drive power generation systems,examining their roles in organic Rankine cycle power generation,gas turbine power generation,supercritical CO2 power generation,vehicle exhaust turbine power generation,and natural gas pressure reduction power generation.Considering the high-speed,high-pressure,high-temperature,and high-efficiency challenges in turbine power generation systems,the key technologies are reviewed including high-speed bearings,rotor dynamics,high-speed motors,high-frequency variable frequency technology,sealing technology,axial force adjustment,thermal management,turbine aerodynamic design,and system control strategies.The article further delves into the current research and development status of high-speed direct-drive power generation systems across different application scenarios.Finally,the article presents prospects for the future development of efficient,reliable and widely adaptable high-speed direct-drive generators,offering valuable insights for researchers and practitioners in the field. 相似文献
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以头部涡流片加主燃孔形式的小型发动机环形回流燃烧室为研究对象,采用Fluent软件进行了数值研究,对比分析了有无主燃孔、主燃孔相对位置以及主燃孔轴向位置对该类型燃烧室主燃区流场、温度场以及出口温度分布的影响。结果表明:该类型燃烧室主要通过火焰筒头部圆形结构、涡流片形成回流区,而内外环主燃孔的射流主要起到截断主流、促进回流区形成以及改变回流区形态的作用;主燃孔相互交错,有利于促进内外环主燃孔的射流相互对冲剪切,形成较为饱满的回流区;主燃孔轴向位置向燃烧室出口方向移动,主燃孔射流截断主流和挤压主流的效果减弱,出口温度分布系数急剧变大。 相似文献
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采用计算流体力学方法研究某给水泵汽轮机调节级在低压喷嘴单独进汽和高低压喷嘴同时进汽两种工况下的三维非定常流动特性,以及动叶因周向不均匀来流而所受到的激振力变化。结果表明:当喷嘴组给定不同进汽参数工质时会造成调节级动叶入口参数周向不均匀,从而影响动叶做功;动叶离开高压区进入低压区前,动叶做功能力最大;动叶离开低压区进入高压区前动叶做负功;叶片上受到的气流激振力主要脉动频率为1倍轴频及其高阶谐频,叶轮转子受到的气流激振力主要脉动频率为1倍叶片通过频率,其受力大小与入口工质初参数有关。 相似文献