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基于CFD的水泵水轮机水泵工况驼峰性能评判研究
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作者 何海平 张勇 +2 位作者 杨光东 唐兆祥 郑津生 《水电站机电技术》 2024年第2期1-6,123,共7页
以两个水泵水轮机模型转轮为研究对象,联合分析了单流道计算结果与模型试验结果,形成了不同转轮方案“驼峰”性能比较的CFD评判方法,对水力设计时“驼峰”性能的优化提供了理论指导,同时对转轮和活动导叶在压力系数“转折点”和“驼峰... 以两个水泵水轮机模型转轮为研究对象,联合分析了单流道计算结果与模型试验结果,形成了不同转轮方案“驼峰”性能比较的CFD评判方法,对水力设计时“驼峰”性能的优化提供了理论指导,同时对转轮和活动导叶在压力系数“转折点”和“驼峰”谷点工况下进行了内部流态分析,对“驼峰”现象的产生原因有了更加深入的了解。结果表明:转轮对比时,压力系数“转折点”流量系数越小,模型试验得到的“驼峰”谷点流量系数越小,压力系数越高,“驼峰”裕度越大;活动导叶近顶盖区域的不稳定流动是单流道计算时压力系数曲线出现“转折点”的主要原因;转轮内部分流体从低压边近上冠侧向高压边近下环侧的流动导致活动导叶近底环区域产生复杂的紊流,严重堵塞了流道,导叶的过流能力下降,是水泵工况出现“驼峰”现象的内因。 展开更多
关键词 水泵水轮机 水泵工况 “驼峰”区 转轮 活动导叶 CFD计算
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The Contribution of the Dromedary in the Spontaneous Plant Seeds Transfer in the Northern Algerian Sahara
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作者 Trabelsi Hafida Senoussi Abdelhakim +1 位作者 Chehma Abdelmadjid Faye Bernard 《Journal of Life Sciences》 2012年第3期300-303,共4页
The current study focuses on the contribution of the dromedary in the preservation and increase of spontaneous flora through seeds transfer by endozoochory. Thus dromedary faeces have been collected in selected area o... The current study focuses on the contribution of the dromedary in the preservation and increase of spontaneous flora through seeds transfer by endozoochory. Thus dromedary faeces have been collected in selected area of region of Ghardaia (Northern Algeria Sahara), since it is one of the three known cameline rangelands during the four successive seasons of the years 2009-2010, in order to examine their seed contents. Our investigation allowed us to invento 1,832 seeds representing 33 different types varying according to the seasons of harvest. The biggest density of seeds was present in summer with 986 seeds, against 424 seeds in winter, 366 seeds in fall and 56 seeds in spring, and of the same way, the biggest number of types was present in summer with 30 types, consistent of the fall season with 26 types, and arrived then the season of winter with 20 types and the one of spring with five types. The gotten results allowed us to appreciate the ecological role of this animal in the desertic ecosystem in the dissemination and the proliferation of the seeds of the spontaneous flora in its fragile and hostile desert environment to the survival of the seeds enveloped in its faeces. 展开更多
关键词 DROMEDARY SEEDS ENDOZOOCHORY Saharan rangelands Gharda'fa.
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