Mass Transfer during Falling Film Evaporation Based on New Multi-Stage Flash Model

2015 ◽  
Vol 48 (7) ◽  
pp. 528-532
Author(s):  
Xiaoyu Quan ◽  
Yongqiang Luo ◽  
Siyuan Qie ◽  
Zheqing Huang ◽  
Chunjiang Liu
Keyword(s):  
Mass Transfer ◽  
Falling Film ◽  
Film Evaporation ◽  
Multi Stage ◽  
Falling Film Evaporation

Falling Film Evaporation in a Rectangular Channel With Different Depth

2002 ◽  
Author(s):  
N. Forgione ◽  
W. Ambrosini ◽  
F. Oriolo ◽  
P. Wackers
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Rectangular Channel ◽  
Water Film ◽  
Experimental Tests ◽  
Heated Plate ◽  
Falling Film ◽  
Plate Temperature ◽  
Film Evaporation ◽  
Falling Film Evaporation

This paper describes the results of experimental tests carried out to study falling film evaporation on a heated flat plate with countercurrent air flowing in a rectangular channel. Experimental tests have been run with different channel depths with respect to a previous facility configuration in order to evaluate the effect of this parameter on the measured heat and mass transfer rates. The present work is then focused on the analysis of the effect that developing flow conditions may have on the evaporation of the falling water film. Three different values of the length over the hydraulic diameter ratio of the channel have been considered: L/D = 11.83, 20.86 and 33.88. Series of dry tests with 45° inclined channel were investigated with inlet nominal velocities of 1, 2.5, 5, 7.5, 9 m/s and with nominal heated plate temperature of 70 °C and 90 °C. Corresponding wet tests were investigated with nominal film flow rate at 60 and 100 g/s, with the same nominal inlet velocities but with a temperature of the heated plate of 70 °C. The obtained results point out interesting parametric trends that provide greater insight into the considered phenomena and support the use of the heat and mass transfer analogy for predicting evaporation rates in the considered range of parameters.

Study on Solar Desalination with Enhanced Falling Film Evaporation

2011 ◽  
Vol 347-353 ◽  
pp. 1542-1548
Author(s):  
Zhi Li Chen ◽  
Li An Hou ◽  
Zhen Jie Ren ◽  
Wen Biao Wang ◽  
Chun Long Zhuang
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Transient State ◽  
Weather Conditions ◽  
Electric Heater ◽  
Falling Film ◽  
Film Evaporation ◽  
Solar Desalination ◽  
Waste Energy ◽  
Falling Film Evaporation

Abstract: Based on the analysis of heat and mass transfer and an empirical correlation, a new desalination unit which utilizes solar or waste energy has been developed and tested. In this desalination, a considerable fraction of the latent and sensible heat was successfully recycled and utilized for enhancing falling evaporation-condensation and preheating seawater via remaining heat. The performance of the unit was tested through experiments using an electric heater as heat source. The results indicate that the unit has excellent transient-state performance for effective heat and mass transfer. As a result of the unit operating with a solar system under practical weather conditions, the yield was about five times greater than that of a conventional single solar basin still with the same thermal energy input. The main factors which influence the freshwater yield were researched and analyzed. The reasonable ranges of some parameters were presented.

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
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Transfer Performance ◽  
Horizontal Tube ◽  
Published Data ◽  
Transfer Performance ◽  
Falling Film ◽  
Film Evaporation ◽  
Falling Film Evaporation ◽  
Wetted Area

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.

Numerical Investigation on the Effect of Tube Geometry and Feeder Height on the Heat Transfer Performance of Horizontal Tube Falling Film Evaporation

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
D. Balaji ◽  
R. Velraj ◽  
M. V. Ramana Murthy
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Film Thickness ◽  
Transfer Rate ◽  
Numerical Study ◽  
Mass Transfer Rate ◽  
Falling Film ◽  
Film Evaporation ◽  
Falling Film Evaporation ◽  
Tube Geometry

Abstract This paper discusses about the effect of tube geometry and liquid feeder height on the heat transfer performance of falling film evaporation over the horizontal heated plain tubes. To investigate this, a two-dimensional computational fluid dynamics (CFD) model was developed, compared, and validated with published data available in the literature. A numerical simulation was carried out for varying liquid load, tube diameter, liquid feeder height, and corresponding changes in the heat transfer co-efficient (HTC), and mass transfer rate was recorded and analyzed. An attempt was also made to measure the thickness of the film around the tubes from the simulation model. Mechanisms that control the factors such as HTC, film thickness, and mass transfer were numerically investigated and discussed in this work. Numerical results indicated that low value of liquid film thickness appears approximately at the angular position of the range between 90 deg and 125 deg. Also the numerical investigation revealed that liquid film thickness decreases and HTC and mass transfer rate increases with the increase of feeder height. No remarkable change in film thickness was observed with increase in the tube diameter. This numerical study also proved that the prediction of thermally developed boundary region on the circumference of the tube could be possible in terms of mass transfer rate. It was also observed from the numerical study that the highest mass transfer rate takes place between the angle 135–165 deg near to the bottom of the tube.

scholarly journals SO2 enhanced desorption from basic aluminum sulfate desulphurization–regeneration solution by falling-film evaporation

RSC Advances ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 5550-5558 ◽  
Author(s):  
Kuo Huang ◽  
Xianhe Deng ◽  
Feiqiang He
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Aluminum Sulfate ◽  
Falling Film ◽  
Film Evaporation ◽  
Falling Film Evaporation ◽  
Different Dimensions ◽  
Basic Aluminum

The heat and mass transfer performances of falling-film evaporation with converging–diverging tubes of different dimensions were studied.

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