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In-5%Cu合金的液态结构与粘滞性研究 总被引:1,自引:0,他引:1
利用高温液态金属X射线衍射仪研究了In-5%Cu合金熔体的结构。结果表明:随温度由400℃升高到900℃,In-5%Cu合金熔体的平均最近邻原子间距ri总体上呈现出减小的趋势,原子配位数Ns的变化比较复杂,R1和Ns都在600℃左右出现转折,原子团簇出现热收缩现象,其结构在600℃附近出现异常变化。利用回转振动粘度仪对In-5%Cu合金在液相线以上不同温度进行粘度测量的结果表明:随温度升高,In-5%Cu合金熔体的粘度值减小,总体上呈现指数变化规律,在600℃左右发生突变.粘度突变温度与结构突变温度一致。 相似文献
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在包晶钢板坯连铸生产过程中,通常使用结晶性能较强的高碱度保护渣以减小渣膜传热量,但易引起摩擦力增大的问题。通过计算和实验,模拟讨论了高碱度保护渣析晶后液渣膜成分和粘度变化趋势。结果表明随着枪晶石的析出,剩余液渣膜碱度降低、粘度增大,特别是析出量超过40%之后这种趋势更加突出。为此提出通过提高保护渣原始碱度以减小析晶对液渣膜粘度性能影响的研究思路,并初步讨论了提高碱度后保护渣的粘度特性变化趋势,结果表明当碱度大于1.3时,熔渣粘度明显减小,且粘温特性相对稳定。可为高拉速包晶钢板坯连铸保护渣设计提供参考。 相似文献
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为了研究新型混输泵球阀内气液两相流动规律,建立了球阀内流场的三维模型,利用CFD软件,对阀内气液两相流动进行了数值模拟。在球阀开启高度为0.005 m时,对含气率分别为20%、40%、60%、80%4种工况的模拟结果进行了分析,得到了不同含气率下的速度场、压力场及气液两相相态分布,探讨了含气率对球阀内气液两相流动的影响规律。结果表明:阀隙处流速较大,压力梯度大,阀座倒角下端易气蚀;含气率对阀内流速大小影响较小,但对流态有影响。气体主要分布在阀球壁附近,远离球壁气体介质减少;当含气量逐渐增大时,气液两相的相界面处波动较大。研究结果揭示了阀内气液两相流动的规律,为内压缩混输泵气液单向阀相界面演化及失稳机制的研究提供参考。 相似文献
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In present paper, a ladle–tundish–mold CFD model and a macrosegregation model were utilized to investigate the effects of the multiple pouring(MP) process on the macrosegregation in a 438-ton steel ingot. Firstly, the model was partially proved as compared to the measured carbon distributions along the transverse sections in the riser of ingot. Then, the comparison between the single pouring(SP) and MP process has been carried out to study their influences on the macrosegregation in ingot. Besides, the predicted macrosegregation results in MP process which introduced the improved riser fixed with an insulating sleeve were compared with that in traditional MP process. The traditional MP process leads to certain favorable initial carbon distribution in the mold, which has some favorable influence on suppressing the positive segregation in ingot. The holding time of the low carbon in the riser is the main factor to suppress the positive segregation in ingot. Improved insulating sleeve can prolong the holding time of the low carbon in the riser and release the positive segregation in the riser of ingot. Improvement of the insulating effect of the riser is an efficient method to control macrosegregation in large steel ingot. 相似文献