HEAT AND MASS-TRANSFER BETWEEN BUBBLES AND A LIQUID
HEAT AND MASS-TRANSFER BETWEEN BUBBLES AND A LIQUID
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DOI：
10.1002/cjce.5450700109
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发表时间：
1992-02-01
影响因子：
2.1
通讯作者：
PARIS, J
中科院分区：
文献类型：
--
作者：
GUY, C;CARREAU, PJ;PARIS, J
热气泡和液体之间的传热和传质现象的理解是特别相关的直接接触加热和蒸发系统，如浸没燃烧设备的设计。在这个过程中，从燃烧器排出的气体被分散在液体中被加热或蒸发，各种模型的预测的温度和蒸汽含量的气泡作为其在液体中的停留时间的函数。基于实际浸没燃烧系统中气泡尺寸、加热时间和蒸发速率的实验测量，讨论和评估了使用球形、椭球形和球帽形气泡的模型，包括有或没有内循环。实验发现，气泡呈球冠状。气泡当量直径在15和25毫米之间，气泡速度在0.4和1.2米/秒之间。所提出的模型用于计算浸没燃烧操作过程中的加热时间和浴的蒸发速率;然后将预测值与实验值进行比较。刚性球冠气泡模型可以较好地预测气泡与液体之间的热质交换。
The understanding of the heat and mass transfer phenomena between hot bubbles and a liquid is particularly relevant to the design of direct contact heating and evaporation systems such as submerged combustion equipment. In this process, exhaust gas from a burner is dispersed in a liquid to be heated or evaporated, Various models for the prediction of the temperature and vapor content of the bubbles as a function of their residence time in the liquid are presented. Based on the experimental measurements of the bubble size and of the heating time and evaporation rate in an actual submerged combustion system, models using spherical, ellipsoidal and spherical-cap bubbles, with or without internal circulation, are discussed and assessed. It is found experimentally that the bubbles are of a spherical cap shape. Bubble equivalent diameters between 15 and 25 mm and bubble velocities between 0.4 and 1.2 m/s are observed. The proposed models are used to compute the heating time and evaporation rate of the bath during a submerged combustion operation; the predictions are then compared to the experimental values. The rigid spherical cap bubble model is found to predict satisfactorily the heat and mass exchanges between the bubbles and the liquid.