EAGER: Pool Boiling of Water on a Binary Surface

水的沸腾传热在我们的日常生活中有应用，例如，在发电、水净化和烹饪方面。当水在表面上沸腾时，大量的热量可以从表面传递到水，而不会导致表面温度的显着增加;因此，沸腾也用于诸如电子设备冷却的应用中，其中大的温度上升是禁止的。然而，当大量的热量必须通过沸腾从一个小区域中移除时，它遇到了称为临界热通量（CHF）极限的危机。在此极限下，快速产生的蒸汽气泡合并以在热表面上形成蒸汽膜，其防止液态水接触表面。该项目追求一种新型的表面，称为二元表面（BiS），用于扩展目前的CHF限制沸腾的水。能够增强BiS上水的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，具有许多表面下的微米/纳米空腔，这些空腔充满了非沸腾液体（NBL），在固体岛屿周围形成水坑。本研究项目的目标有两个方面：（1）实验测量CHF和水在铜油BiS（油是NBL）上的池沸腾传热系数，并将其与亲水和疏水表面上获得的CHF和传热系数进行比较;（2）获得BiS上发生非均质气泡成核的假设的证据。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。该项目有助于建立一种新的沸腾增强机制的可行性，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知识价值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.