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ACRT过程Ekman流场的实验研究
EXPERIMENTAL STUDY OF THE ACRT EKMAN FLOW
【摘要】 利用水模拟实验,研究了ACRT(坩埚加速旋转技术)过程中Ekman流场的稳定性,及其与坩埚内径Φ,转速最大差值△ωmax,及坩埚中液体高度H的关系。结果表明,当雷诺数Re=0.678R(|△ωmax|/v)0.5≤ReCl(下临界值)时,Ekman流场稳定;Re≥ReC2(上临界值)时,减速过程的Ekman流场完全不稳定。当Re≤ReCl时,Ekman流区的高度h随Φ及△ωmax增加而增加,Ekman流区相对高度h/R(R=0.5Φ)与Re2呈线性关系,直线的斜率k与R有关;当坩埚中液柱高度H减小到某一临界值H时,Ekman流区随H的减小而减小。
【Abstract】 The stability of the Ekman flow during ACRT (accelerated crucible rotation technique) process, and the effects of the crucible diameter Φ, the maximum variation of the rotation speed, △ωmax , as well as the liquid height H in the crucible on the Ekman flow,were studied with hydraulic analogue experiments. The result shows that, if Reynolds number Re ≤ ReC1(the low critical Re), the Ekman flow is stable, if Re≥ ReC2(the high critical Re), the Ekman flow during the crucible deceleration period is unstable, and the Ekman flow height h increases with increase of the crucible diameter Φ and the maximum variation of the rotation speed △ωmax . When Re≤ ReC1, the relation between the ratio h / R (R = 0.5Φ) and Re2 is linear. When the liquid height H< H(a critical value), the Ekman flow height h decreases with decrease in the liquid height H.
- 【文献出处】 金属学报 ,ACTA METALLRUGICA SINICA , 编辑部邮箱 ,1996年03期
- 【分类号】TG115
- 【被引频次】5
- 【下载频次】72