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

文献中报道的大多数流动沸腾传热相关性利用池沸腾相关性来模拟传热的微对流成分。然而，似乎有足够的证据表明，控制流动沸腾中蒸汽泡的开始、生长和离开的物理规律与池沸腾中的不同。在这种情况下，使用池沸腾相关性来模拟流动沸腾传热的微对流部分是值得怀疑的。拟进行的研究将包括实验测量饱和强迫对流核沸腾中的成核点密度、蒸汽泡生长速率和蒸汽泡偏离直径。液膜厚度、质量通量、重力取向、壁过热度、热力学性质和受热面特性对这些参数的影响方式将被深入研究。局部蒸汽体积分数和液膜厚度将采用辐射吸附技术测量。成核位置密度将与液晶可视化技术相结合来确定。蒸汽泡的生长速率和离开直径将用高速摄影测量。利用收集到的实验数据，建立了流动沸腾过程中汽泡发生、生长和离开的相关关系。

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.