scholarly journals CFD studies on the influence of un-wetted area on the heat transfer performance of the horizontal tube falling film evaporation

2021 ◽  
pp. 56-56
Author(s):  
Dilli Balaji ◽  
Ramalingam Velraj ◽  
Malavarappu Ramanamurthy

This paper discusses about the effect of un-wetted area of tube on the heat transfer performance of horizontal tube falling film evaporation. A 2D CFD model was developed to perform simulations and investigate the output and validated them with published data available in the literature. In the present study the VOF method is used to track the boundary of the liquid vapour from the contours of volume fraction. Effect of varying tube wall temperature or wall super heat (6 to 11?C) on un-wetted area, heat transfer co-efficients and mass transfer co-efficients of the circular tube were obtained from the simulation model and the results were analysed and reasons were identified and discussed here. The threshold value of wall super heat above which phase change occurs between liquid film and tube surface is identified as 6?C. Also it is noted that mass transfer rate increases and then decreases with increase of wall super heat and heat transfer co-efficient showed declining trend.

2011 ◽  
Vol 236-238 ◽  
pp. 1572-1575 ◽  
Author(s):  
Hong Liu ◽  
Hu Gen Ma ◽  
Chang Sheng Li

Experimental investigation of falling film evaporation on horizontal tubes was carried out in this paper. Tube surface, spray flow rate and coolant flow rate were the factors considered in the experiment. The impact on falling film evaporation performance was obtained as expected. Experimental results are obtained that the heat transfer performances of low finned tubes are better than that of smooth tubes. The increasing of flow rate enhances heat transfer performance of falling film evaporation at first, while the flow rate gets a certain value, it will hinder the improvement of heat transfer performance. It was also found that there is almost no effects on heat transfer coefficient when the flow rate of coolant changes.


2012 ◽  
Vol 614-615 ◽  
pp. 296-300 ◽  
Author(s):  
Wei Kang Hu ◽  
Li Yang ◽  
Lei Hong Guo

This paper mainly studies the falling film evaporator in the field of water desalination. Using the method of fluent simulates the process of the liquid flowing and heat-transfer on the horizontal-tube falling film evaporation. The author analyses the distribution of the liquid film, and obtain the rule that spray density, evaporation temperature, temperature difference and pipe diameter affect the performance of heat-transfer in a certain range. So the paper plays a guiding role in heat transfer enhancement in the falling film evaporator.


Desalination ◽  
2016 ◽  
Vol 394 ◽  
pp. 64-71 ◽  
Author(s):  
Luopeng Yang ◽  
Yang Liu ◽  
Yan Yang ◽  
Shengqiang Shen

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