Experimental study on overall heat transfer coefficient of seawater on three tube arrangements for horizontal-tube falling film evaporator

2015 ◽  
Vol 57 (21) ◽  
pp. 9993-10002 ◽  
Author(s):  
Xingsen Mu ◽  
Shengqiang Shen ◽  
Yong Yang ◽  
Gangtao Liang ◽  
Xue Chen ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Horizontal Tube ◽  
Falling Film ◽  
Film Evaporator ◽  
Overall Heat Transfer Coefficient

Heat Transfer Coefficient in Falling Film Evaporators With Different Tube Arrangements

2012 ◽  
Author(s):  
Shengqiang Shen ◽  
Gangtao Liang ◽  
Yali Guo ◽  
Xingsen Mu ◽  
Rui Liu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Temperature Difference ◽  
Saturation Temperature ◽  
Horizontal Tube ◽  
Falling Film ◽  
Overall Heat Transfer Coefficient ◽  
Spray Density ◽  
Total Temperature

A set of experimental facilities were set up to measure overall heat transfer coefficient of horizontal-tube falling film evaporators with triangular, rotated square and square-pitch bundles. Effect of spray density, saturation temperature, total temperature difference and inlet steam velocity on the overall heat transfer coefficient K is studied respectively. The tubes are made of HAL77-2A aluminium brass with an outer diameter of 25.4 mm. Fluids inside and outside the tubes are steam and fresh water respectively. The results indicate that growth of spray density and saturation temperature helps to increase the K. The K could also be increased by reducing the total temperature difference. However, the impact of the inlet steam velocity on the K is less significant. The K in the evaporator with rotated square-pitch arrangement is supreme. Furthermore, space distribution of local overall heat transfer coefficient K̃ in the evaporators is also discussed. Based on this investigation, basic engineering design information will be provided to establish the governing parameters for horizontal-tube falling film evaporator in the field of seawater desalination.

scholarly journals Heat-transfer characteristics of ammonia-water falling film generation outside a vertical tube

2017 ◽  
Vol 21 (3) ◽  
pp. 1251-1259 ◽  
Author(s):  
Chao Luo ◽  
Jun Zhao ◽  
Weibin Ma
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Water Temperature ◽  
Water Solution ◽  
Hot Water ◽  
Falling Film ◽  
Ammonia Water ◽  
Overall Heat Transfer Coefficient ◽  
Spray Density

A heat transfer experimental of vertical out-tube falling film was conducted with different inlet spray density of ammonia-water solution and inlet hot water temperature. The inlet liquid mass concentration was selected as 60% of ammonia. The experiments showed that the overall heat transfer coefficient increases with the increase of inlet spray density and a maximum overall heat transfer coefficient could be obtained in an optimum spray density of ammonia-water solution, ?, between 0.26 and 0.29 kg/ms. The generation of ammonia vapor outside the vertical falling film had a similar trend with the overall heat transfer coefficient basing on different spray density. The effect of hot water temperature difference, ?T, on overall heat transfer coefficient showed that ?T between 10 and 13 K is the optimum temperature difference of the vertical falling film generation

scholarly journals Establishment of the falling film evaporation model and correlation of the overall heat transfer coefficient

2019 ◽  
Vol 6 (5) ◽  
pp. 190135 ◽  
Author(s):  
Jing Fang ◽  
Kaixuan Li ◽  
Mengyu Diao
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Temperature Distribution ◽  
Film Thickness ◽  
Liquid Film ◽  
Velocity Distribution ◽  
Transfer Coefficient ◽  
Falling Film ◽  
Overall Heat Transfer Coefficient ◽  
Proposed Model

In order to study the heat transfer of the falling film evaporator with phase change on both sides, in this paper we built the mathematical model and the physical model where the liquid film inside the tube is laminar and turbulent. The film thickness of the condensate at different axial positions, total condensate volume and velocity distribution, and temperature distribution of condensate outside the tube can be obtained by calculating the proposed model. Meanwhile, the liquid film thickness, velocity distribution and temperature distribution inside the tube were obtained by numerical simulation by considering the influence of the liquid film with different compositions on the heat transfer during fluid flow. With ethanol–water as the system, the overall heat transfer coefficient and heat transfer quantity of the falling film evaporator were obtained by the calculation of the model. The accuracy of the proposed model was confirmed by experiments. The model and the calculation of heat transfer proposed in this paper have enormous significance for the basic data and theoretical guidance of the heat transfer performance prediction and operational optimization of the evaporator.

Experimental Study of Heat Transfer Characteristics for Horizontal-Tube Falling Film Evaporation

2012 ◽  
Author(s):  
Xingsen Mu ◽  
Yong Yang ◽  
Shengqiang Shen ◽  
Gangtao Liang ◽  
Luyuan Gong
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Fresh Water ◽  
Horizontal Tube ◽  
Falling Film ◽  
Heat Transfer Characteristics ◽  
Film Evaporation ◽  
Transfer Characteristics ◽  
Falling Film Evaporation

The horizontal-tube falling film evaporation is a widely adopted technique in multiple-effect distillation (MED) desalination plant due to the higher heat transfer coefficient under quite small temperature differences. In the present study, an experimental platform for horizontal-tube falling film evaporation was set up to measure its heat transfer characteristics. Results indicate that heat transfer coefficient (h) for both fresh water and seawater are almost independent with heat flux. The h increases firstly and then decreases with growth of Re. Along the tube circumference, the h increases after decreasing. In addition, the distribution of h for fresh water and seawater at the different evaporation temperatures and Reynolds number (Re) are also provided.

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