EAGER: Pool Boiling of Water on a Binary Surface

将水煮沸以传递热量在我们的日常生活中有着广泛的应用，例如在发电、净水和烹饪方面。当水在表面沸腾时，大量的热量可以从表面转移到水中，而不会导致表面温度的显著上升；因此，沸腾也用于电子产品的冷却，在这些应用中，大幅温升是令人望而却步的。然而，当必须通过沸腾从一小块区域中移走大量热量时，它会遇到一个称为临界热流密度(CHF)极限的危机。在这一极限下，快速产生的蒸汽泡合并，在高温表面形成一层蒸汽膜，防止液态水接触表面。这个项目追求一种新型的表面，称为二元表面(S)(BIS)，用于延长当前CHF沸腾水的限制。增强BIS沸腾性能的基础科学将通过YouTube视频与公众分享。BIS是一种高度润湿的表面，有许多亚表面微/纳米空腔，其中填充了非沸腾液体(NBL)，在固体岛屿周围形成水坑。本研究项目的目的有两个：(1)实验测量铜-油双界面(油为NBL)上水池沸腾的CHF和换热系数，并与在亲水和疏水表面测得的结果进行比较；(2)为双界面上存在非均相气泡成核的假设提供证据。为了实现这一目标，计划进行两项工作，包括池沸腾实验和实验前后的BIS表面制备和分析。这个项目有助于建立一种新的沸腾强化机制的可行性，该机制可能在许多领域产生重大影响。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Boiling of water to transfer heat has applications in our day-to-day lives, e.g., in power generation, water purification, and cooking. When water boils over a surface, substantial amounts of heat can be transferred from the surface to the water without causing a significant increase in the surface temperature; hence, boiling is also used in applications such as cooling of electronics where large temperature rises are prohibitive. However, when a large amount of heat must be removed from a small area through boiling, it encounters a crisis called the Critical Heat Flux (CHF) limit. At this limit, the rapidly generated vapor bubbles merge to form a vapor film on the hot surface which prevents liquid water to contact the surface. This project pursues a new type of surface, called the Binary Surface(s) (BiS), for extending the current CHF limits for the boiling of water. The underlying science that enables enhanced boiling performance of water on BiS will be shared with the public through YouTube videos.A BiS is a highly wetting surface with many sub-surface micro-/nano-cavities, which are filled with a Non-Boiling Liquid (NBL) creating puddles around solid islands. The goal of this research project is two-fold: (1) to experimentally measure the CHF and the Heat Transfer Coefficient for the pool boiling of water on a copper-oil BiS (oil is the NBL) and compare them with those obtained on hydrophilic and hydrophobic surfaces and (2) to obtain evidence for the hypothesis that heterogeneous bubble nucleation occurs on a BiS. Two tasks are planned to realize this goal and they include pool boiling experiments and BiS surface preparation and analysis before and after the experiments. This project helps to establish the feasibility of a new boiling enhancement mechanism that could have a significant impact in many fields.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.