Flow Prediction and Fluctuation-sensitivity Investigations for Quasi-steady Shear Driven Condensing Flows in Milli-meter to Micro-meter Scale Two-Phase Systems

1033591 Narain这项研究将有助于发展涉及液-汽相变的微尺度热系统。为了达到理想的系统性能，通常情况下，剪切驱动的准稳态冷凝流必须以可预测和可维护的方式运行。因此，毫米至微米级冷凝器需要可靠的流量预测能力。智力优势：这项研究旨在量化的波动能量传递机制，从冷凝流，可能会导致显着的瞬态行为内和外的微型冷凝器。实验涉及三个不同的测试部分（水平间隙或管的特征尺寸为200微米至2毫米）在一个仪表流动回路设施将导致测量的定量信息如何一个小型冷凝器响应-动态和热-通过其入口和出口转移的波动能量。要测量的参数包括传热系数、压降和其他对成功设计和运行至关重要的重要标准。实验研究将通过模拟增强，以产生适用于各种几何形状和各种冷凝表面温度条件的预测能力。更广泛的影响：流动沸腾和冷凝在许多应用中具有满足高热流需求的潜力。这项研究将能够更定量地预测流动和传热的小型冷凝器。这项研究将涉及从代表性不足的群体中招募的研究生和本科生。

1033591NarainThis research will aid the development of microscale thermal systems that involve liquid-vapor phase change. To achieve desired system performance, it is often the case that shear-driven quasi-steady condensing flows must be made to behave in a predictable and maintainable fashion. Reliable flow prediction capability is therefore needed for millimeter-to-micrometer scale condensers. Intellectual Merit: This research seeks to quantify the fluctuation energy transfer mechanisms to and from a condensing flow that might cause significant transient behavior within and outside of a microscale condenser. Experiments involving three different test sections (horizontal gaps or tubes with characteristic dimensions of 200 micrometers to 2 millimeters) in an instrumented flow-loop facility will lead to measured quantitative information on how a small-scale condenser responds - dynamically and thermally - to fluctuation energy transferred through its inlet and outlet. Quantities to be measured include heat transfer coefficients, pressure drops, and other important criteria that are crucial for successful design and operation. The experimental study will be augmented with simulations to generate a predictive capability applicable to a wide array of geometries and various condensing surface temperature conditions.Broader Impacts: Flow boiling and condensation has promising potential to meet high heat flux needs in many applications. This research will enable a more quantitative prediction of flow and heat transfer in small scale condensers. The research will involve graduate students and undergraduate students recruited from underrepresented groups.