水平管降膜蒸发器中液膜厚度周向分布研究

发布时间：2018-03-02 23:04

本文选题：计算流体动力学　切入点：水平管　出处：《太阳能学报》2016年12期 　论文类型：期刊论文

【摘要】：采用VOF模型对水平管表面液膜厚度分布进行数值研究,并将结果与实验数据进行比较,二者吻合较好。结果表明:液膜沿水平管周向的流动可分为瞬态过程及之后的稳态过程,瞬态过程包括液体自由下降、冲击管壁、液膜发展、充分发展以及脱离管壁5个阶段。稳态过程中,液膜厚度沿圆管周向分布为先减小,再增大。水平管上、下半部液膜厚度分布不对称,顶部和底部存在两个切向速度滞点,下部滞点处可能会出现无液区。随着液膜雷诺数的增大,液膜厚增大,下部无液区范围也增大。较大的管径会导致液膜在同一角位置处流速增加,液膜厚度减小。
[Abstract]:The VOF model is used to numerically study the thickness distribution of liquid film on the surface of horizontal tube. The results are in good agreement with the experimental data. The results show that the flow of liquid film along the circumferential direction of horizontal tube can be divided into transient process and subsequent steady state process. The transient process includes five stages: free drop of liquid, impingement on pipe wall, development of liquid film, full development and separation from tube wall. In the steady state process, the thickness of liquid film decreases first and then increases along the circumferential direction of the pipe. There are two tangential velocity hysteresis points at the top and bottom, and there may be no liquid region at the lower hysteretic point. With the increase of Reynolds number of liquid film, the thickness of liquid film increases, and the thickness of liquid film increases with the increase of Reynolds number of liquid film. The larger diameter of the tube will lead to the increase of the velocity of the liquid film at the same angle and the decrease of the thickness of the liquid film.
【作者单位】：大连理工大学能源与动力学院;
【基金】：国家自然科学基金面上项目(51376035)
【分类号】：TK124

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