摘要
为研究CAP1400核主泵事故工况下的空化性能,采用标准k-ε模型和Mixture模型,开展了CAP1400核主泵1∶2.5模型泵的整机空化数值模拟.分析了模型泵空化初生时的空化特性和不同空化余量下叶轮内空化发展规律,以及叶片中间流线上的载荷特性,并采用砂铸叶轮、精铸铝制叶轮与砂铸导叶结合开展了模型泵性能的试验研究,结果表明:蜗壳与叶轮的相对位置对叶轮内空泡体积分布具有一定的影响,靠近蜗壳出口的叶片吸力面空化更加严重,空化的排挤效应改变了叶片进口附近的液流角并导致压力面前缘出现空化;空化对叶片载荷影响较大,发生空化后叶片载荷在沿流线吸力面空泡结束的位置附近会出现极大值,且叶轮内空化区域的不均匀分布加大了不同叶片之间的载荷差异,靠近蜗壳出口的叶片沿流线压力载荷的极大值最大;叶轮的制造精度对泵的空化性能有较大影响.
In order to investigate the cavitation performance of CAP1400 reactor coolant pump,the standard k-ε model and mixture model were applied to simulate the cavitating flow in a 1 ∶ 2.5 CAP1400 model pump. The cavitation inception was reaveled and cavitation development in the impeller and the blade loading characteristics on the middle stream line at different NPSH were analyzed.Furthermore,the cavitation experiment was carried out with sand casting guide vane combined with precision casting aluminum alloy impeller and sand casting impeller respectively. The results show that the relative position of the volute and impeller has a certain effect on the vapor volume fraction distribution in the impeller and the cavitation is more serious on the suction surface of blade near the outlet of the volute. Blockage effect of cavitation changes the flow angle near the leading edge of blade,whichcauses the cavitation arising on the pressure surface near the leading edge. Blade loading is significantly influenced by cavitation. Blade loading along the streamline has a maximum value near the end of vapor on the suction surface. Uneven distribution of the vapor in the impeller increases the difference of blade loading among different blades. The manufacturing precision of the impeller has a great impact on the cavitation performance of pump.
引文
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