Development of heat and mass transfer coefficient correlations for natural packings used in solar desalination process

2019 ◽  
Vol 153 ◽  
pp. 46-53
Author(s):  
K. Zhani ◽  
S. Mejbri
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Heat And Mass Transfer ◽  
Solar Desalination

scholarly journals Development of mass and heat transfer coupled model of hollow fiber membrane for salt recovery from brine via osmotic membrane distillation

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Sher Ahmad ◽  
Gabriela Vollet Marson ◽  
Waheed Ur Rehman ◽  
Mohammad Younas ◽  
Sarah Farrukh ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Heat And Mass Transfer ◽  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Membrane Distillation ◽  
Fiber Membrane ◽  
Salt Recovery ◽  
Osmotic Solution

Abstract Background In this research work, a coupled heat and mass transfer model was developed for salt recovery from concentrated brine water through an osmotic membrane distillation (OMD) process in a hollow fiber membrane contactor (HFMC).The model was built based on the resistance-in-series concept for water transport across the hydrophobic membrane. The model was adopted to incorporate the effects of polarization layers such as temperature and concentration polarization, as well as viscosity changes during concentration. Results The modeling equations were numerically simulated in MATLAB® and were successfully validated with experimental data from literature with a deviation within the range of 1–5%. The model was then applied to study the effects of key process parameters like feed concentrations, osmotic solution concentration, feed, and osmotic solution flow rates and feed temperature on the overall heat and mass transfer coefficient as well as on water transport flux to improve the process efficiency. The mass balance modeling was applied to calculate the membrane area based on the simulated mass transfer coefficient. Finally, a scale-up for the MD process for salt recovery on an industrial scale was proposed. Conclusions This study highlights the effect of key parameters for salt recovery from wastewater using the membrane distillation process. Further, the applicability of the OMD process for salt recovery on large scale was investigated. Sensitivity analysis was performed to identify the key parameters. From the results of this study, it is concluded that the OMD process can be promising in salt recovery from wastewater.

An Inverse Method for Drying at High Mass Transfer Biot Number

2003 ◽  
Author(s):  
Gligor H. Kanevce ◽  
Ljubica P. Kanevce ◽  
George S. Dulikravich ◽  
Marcelo J. Colac¸o
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Heat And Mass Transfer ◽  
Biot Number ◽  
Temperature Sensitivity ◽  
Sensitivity Coefficient ◽  
The Heat Transfer Coefficient

The inverse problem of using temperature measurements to estimate the moisture content and temperature-dependent moisture diffusivity together with the heat and mass transfer coefficients is analyzed in this paper. In the convective drying practice, usually the mass transfer Biot number is very high and the heat transfer Biot number is very small. This leads to a very small temperature sensitivity coefficient with respect to the mass transfer coefficient when compared to the temperature sensitivity coefficient with respect to the heat transfer coefficient. Under these conditions the relative error of the estimated mass transfer coefficient is high. To overcome this problem, in this paper the mass transfer coefficient is related to the heat transfer coefficient through the analogy between the heat and mass transfer processes in the boundary layer. The resulting parameter estimation problem is then solved by using a hybrid constrained optimization algorithm OPTRAN.

Convective Mass Transfer Coefficient at Wooden Surface in Jet Drying of Veneer

Holzforschung ◽  
1999 ◽  
Vol 53 (2) ◽  
pp. 204-208 ◽  
Author(s):  
Antti Hukka ◽  
Olli Oksanen
Keyword(s):  
Mass Transfer ◽  
Moisture Content ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Heat And Mass Transfer ◽  
Correction Factor ◽  
Average Moisture Content ◽  
Correction Coefficient ◽  
Convective Mass Transfer ◽  
Wooden Surface

Summary The relationship between heat and mass transfer at wooden surface is investigated experimentally by drying 1.6 mm thick birch veneers in constant conditions in a laboratory-scale roller dryer. By intermediate weighing of the samples a drying curve is established for each specimen. The drying curves are formulated in a functional form to produce the drying rate as a function of wood moisture content. Based on that and the measured heat-transfer coefficient a correction factor is calculated for the mass transfer coefficient predicted by the boundary layer theory. The results show that the convective mass transfer coefficient for wooden surfaces substantially deviates from that given by the analogy between heat and mass transfer. The correction factor describing the internal resistance for evaporation is strongly dependent on wood temperature within the range 50–90°C, but for practical purposes not dependent on the average moisture content of the veneer (range 40–70%). The numerical value of the correction coefficient established is somewhat lower than published earlier by other researchers.

Dynamic model of saturator based on a global heat and mass transfer coefficient

2018 ◽  
Vol 25 (5) ◽  
pp. 1173-1181
Author(s):  
Di Huang ◽  
Deng-ji Zhou ◽  
Hui-sheng Zhang ◽  
Ming Su ◽  
Shi-lie Weng
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Heat And Mass Transfer ◽  
Dynamic Model

Characteristics of Heat and Mass Transfer in Condesation Process of Gas-Liquid Cross Flow

2014 ◽  
Vol 1070-1072 ◽  
pp. 1718-1721
Author(s):  
Feng Zhen Zhang ◽  
Xie Ma ◽  
Hu Yang ◽  
Xing Yong Liu ◽  
Huai Ming Du
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Heat And Mass Transfer ◽  
Gas Flow ◽  
Cross Flow ◽  
Condensation Process ◽  
Gas Flow Rate ◽  
Staggered Arrangement ◽  
Main Factors

The condensation process of liquid-gas cross flow was mathematically modeled, and the expressions of heat and mass transfer coefficient were obtained. The characteristics of high temperature and humidity gas that flowed across an array of liquid columns were experimentally studied in various working conditions to get the heat and mass transfer coefficient. The results showed that: the heat and mass transfer coefficient of the staggered arrangement is 20~40% higher than that of the aligned arrangement; the gas turbulence near the gas-liquid interface caused by the flow of the liquid columns and that caused by the gas flow around liquid columns are the main factors that intensify the heat and mass transfer in low and high gas flow rate respectively.

Determination of Heat and Mass Transfer Coefficients by Condensation in an Air Cooler

2007 ◽  
Author(s):  
Fatemeh Esfandiari Nia ◽  
Dolf van Paassen
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Heat And Mass Transfer ◽  
Lewis Number ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Air Cooler ◽  
Air Conditioning Systems

This paper describes an improved class of heat and mass transfer air cooler model. The model is based on the approach of Green [1]. It delivers a compact and fast model that is appropriate for year round simulations of air conditioning systems. The model is validated through a set of experiments in the laboratory with an air cooler of eight rows. The heat transfer coefficients have been derived from the standard relations. For a good agreement between the measurements of a wet cooler and the model solutions, a substantial correction in the heat transfer coefficients is needed. In addition, the results obtained from the measurements indicated that the heat transfer coefficient itself and the correlation between heat and mass transfer had to be adapted. Acceptable results were obtained when mass transfer coefficient was adjusted by a correction factor. The decrease in heat transfer has been observed with an increase in dehumidification and the same could be concluded from the coupling of heat and mass transfer. The fins are not completely wet, which implies that an analogy between sensible and latent heat only partly exists. The model does not take wetness of the pipe into account. To overcome this problem, the Lewis number is modulated, based on the degree of dehumidification. In other words, the smaller mass transfer coefficient, there is the higher the dehumidification.

Comparison of Heat and Mass Transfer Characteristics of Absorption of R134a in DMAC and DMF for a Falling Film Horizontal Tube Absorber

2014 ◽  
Author(s):  
Kamal Kant Yadu ◽  
Shaligram Tiwari ◽  
Prakash Maiya Manoor
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Heat And Mass Transfer ◽  
Numerical Technique ◽  
Horizontal Tube ◽  
Computer Code ◽  
Mean Value ◽  
Falling Film ◽  
Transfer Characteristics

The present work is a comparative study of heat and mass transfer behaviour during the absorption of R134a (1, 1, 1, 2 Tetrafluroethane) vapour into absorbents, DMAC (N, N-Dimethylacetamide) and DMF (N, N-Dimethylformamide). Initially, the heat and mass transfer characteristics for absorption of R134a into DMF for a falling film horizontal tubular absorber have been investigated by employing a two-dimensional numerical technique. The related governing equations are solved using a developed computer code in MATLAB. Then, a comparison of absorption characteristics of R134a-DMAC and R134a-DMF is made. For the mean value of operating parameters considered, the R134a-DMF solution absorbs more due to higher diffusion coefficient value of DMF than DMAC. The mass transfer coefficient is observed to decrease at a steeper rate at the entrance of the first tube for both working fluids, after which gradual decrease in the mass transfer coefficient is observed further downstream.

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