Prediction and Attainment Capability for Quasi-Steady Internal Condensing Flows: An Integrated Experimental/Computational Approach

在管道中实现稳定或准稳定的环形或分层内部冷凝流动（对于任何给定的进口压力，质量流量和冷凝表面温度分布）取决于冷凝器部分热量排出率和出口压力条件之间的兼容性，或者，等效地，出口蒸汽流量分数。在某些出口条件下，可以实现准稳定的波状界面流动，而在其他条件下，明显的压缩性振荡将持续存在。这些尚未解决的问题将在电子流动控制技术的帮助下进行实验研究，该技术有助于确定在不同出口条件下可实现准稳定流动的条件范围。该实验还将允许对内径为6.35 mm、长度为0.8 m的管内环状膜凝结进行新的观察和测量。管道和随后的通道可以从垂直向下到水平配置。我们还提出了采用荧光技术测量时变冷凝膜厚度的方法，该方法适用于掺杂双电制冷剂如FC-72等的沸腾和冷凝流。从这些测量中，可以发现平均结构和波浪结构。将提出的实验研究结果与计算模拟和环路热管等应用相关联。

Proposal Number: CTS-0086988Principal Investigator: A. NarainAbstractAchievement of steady or quasi-steady annular or stratified internal condensing flows in pipe (for any given inlet pressure, mass flow rate, and condensing surface temperature distribution) is dependent on compatibility between the condenser-section heat removal rate and exit pressure condition, or, equivalently, exit vapor flow rate fraction. For certain exit conditions, quasi-steady wavy-interface flows are realized and, for other conditions, significant compressibility-induced oscillations will persist. These unresolved issues will be experimentally investigated with the help of electronic flow control techniques which assist in identifying the range of conditions for which quasi-steady flows are achievable for different exit conditions. The experiment will also allow for novel observations and measurements for annular film condensation in 6.35 mm inner diameter pipe of 0.8 m length. The pipe, and subsequently channel, may operate from vertically downward to horizontal configurations. We also propose to measure time-varying condensate film thickness by fluorescence technique applicable to boiling and condensing flows of doped di-electric refrigerants such as FC-72, etc. From these measurements, mean and wave-structure may be found. Separate efforts relate the results of the proposed experimental research to computational simulations and applications such as Looped Heat Pipes, etc.