Transition Pool Boiling Heat Transfer Mechanisms on a Strip Heater Using Microscale Heater Arrays

该奖项的目的是利用独立控制的加热器对过渡沸腾过程中的局部传热系数进行实验研究。大多数现有的数据是相对较大的表面上的平均系数。这项工作将利用一组微尺度加热器，每个加热器都小于平均气泡尺寸，以控制局部加热并测量局部系数。通过精确地确定在蒸汽离开循环的时间和地点，大量的热量从壁上被带走，并将这些信息与在这些时候对流体状态的视觉观察相关联，将获得关于过渡沸腾过程中重要的传热机制的信息。这一信息也有助于提高对临界热通量的理解。将获得关于壁面空隙率、液体接触持续时间和液体接触分布的额外数据。该实验技术有望应用于喷雾冷却、冲击冷却、颗粒冲击换热等领域。

This award is to study experimentally the local heat transfer coefficients during transitional boiling using independently controlled heaters. Most of the existing data are for average coefficients over relatively large surfaces. This work will utilize an array of microscale heaters, each smaller than the average bubble size, to control local heating and to measure local coefficients. By pinpointing when and where in the vapor departure cycle large amounts of heat are removed from the wall and correlating this information to visual observations of the state of the fluid at those times, information about the important heat transfer mechanisms during transitional boiling will be obtained. This information can also lead to an improved understanding of the critical heat flux. Additional data will be obtained regarding wall void fraction, liquid contact duration, and the distribution of liquid contact will be secured. The experimental technique is expected to be applicable to spray cooling, impingement cooling, and particle impingement heat transfer.