Effect of Heaving on Forces Acting on Bubbles in Heating Surface
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摘要: 分析起伏运动条件下过冷沸腾垂直上升流中壁面汽泡的受力,研究垂直方向加速度的变化对壁面汽泡浮力的直接影响,以及垂直方向加速度的变化引起系统流量的波动对汽泡受力的间接影响。起伏运动条件与静止条件下汽泡受力的对比计算分析表明,起伏运动对自然循环回路中汽泡受力的影响大于强迫循环下的影响;起伏运动对自然循环的影响取决于流量的波动,对强迫循环的影响取决于浮力项在汽泡受力平衡中所占权重;汽泡受力平衡的改变将影响汽泡滑移或脱离点的位置,进而影响沸腾传热。Abstract: The effect of heaving on forces acting on bubbles in sub-cooled boiling flow has been analyzed.The buoyancy is directly affected by the heaving acceleration.And the flow rate fluctuation which is caused by the heaving acceleration imposes the forces acting on bubbles indirectly.The forces acting on bubbles under heaving and non-heaving condition have been computed and compared.The results show that heaving has less effect upon forced circulation than natural circulation.The influence of heaving upon natural circulation depends on flow rate fluctuation and the influence of heaving upon forced circulation depends on the weight of buoyancy in the balance of forces acting on bubble.Heaving influences the forces acting on bubbles,which may change the position of vapor bubble departure,hence affects the heat transfer in boiling flow.
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Key words:
- Heaving /
- Acceleration /
- Sub-cooled boiling /
- Forces on bubble
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