Research Initiation Awards: Forced Convection Boiling Vapor Bubble Nucleation, Growth, and Departure: REU Supplement

大多数流动沸腾传热关联式 文献中的报告利用池沸腾关联式 来模拟热传递的微对流成分。 然而，有足够的证据表明， 控制着蒸汽的开始、增长和离开 流动沸腾中的气泡不同于池沸腾中的气泡。 在这种情况下，使用池沸腾关联式 模拟流动沸腾热的微对流分量 转移是值得怀疑的。 拟议的调查将包括实验 测量成核点密度、汽泡生长 饱和压力下的汽泡脱离直径 对流核态沸腾 液体的方式 膜厚，质量通量，重力取向，壁面 热力学性质和受热面 影响这些参数的特性将被彻底 研究了 局部汽相体积分数和液膜 将使用辐射吸收测量厚度 法 将确定成核位置密度 在化学上与液晶结合， 可视化技术 汽泡生长速率和 出发直径将使用高速测量 电影摄影. 利用收集的实验数据， 水汽起始、增长和离开的关联式 将产生流动沸腾中的气泡。

The majority of flow boiling heat transfer correlations reported in the literature utilize pool boiling correlations to model the microconvection component of heat transfer. However, there appears sufficient evidence that the physics governing the incipience, growth, and departure of vapor bubbles in flow boiling differs from that in pool boiling. Under such circumstances, the use of pool boiling correlations to model the microconvection component of flow boiling heat transfer would be questionable. The proposed investigation will consist of experimentally measuring the nucleation site density, vapor bubble growth rate, and vapor bubble departure diameter in saturated forced convection nucleate boiling. The manner in which the liquid film thickness, mass flux, gravitational orientation, wall superheat, thermodynamic properties, and heating surface characteristics influence these parameters will be thoroughly investigated. The local vapor volume fraction and liquid film thickness will be measured using a radiation adsorption technique. The nucleation site density will be determined photographically in conjection with a liquid crystal visualization technique. The vapor bubble growth rate and departure diameter will be measured using high speed cinematography. Using the experimental data to be collected, correlations for the incipience, growth and departure of vapor bubbles in flow boiling will be developed.