Heat and mass transfer coefficients of falling-film absorption process

2005 ◽  
Vol 48 (13) ◽  
pp. 2779-2786 ◽  
Author(s):  
Isamu Fujita ◽  
Eiji Hihara
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Falling Film ◽  
Absorption Process ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Falling Film Absorption ◽  
Film Absorption

Effect of Nanoparticles on H2O/LiBr Falling Film Absorption Process

2016 ◽  
Author(s):  
L. Y. Zhang ◽  
Y. Li ◽  
Y. Wang ◽  
L. X. Cao ◽  
X. Z. Meng
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Fe3o4 Nanoparticles ◽  
Falling Film ◽  
Absorption Process ◽  
Nanoparticle Concentration ◽  
Water Vapor Absorption ◽  
Libr Solution ◽  
Falling Film Absorption ◽  
Film Absorption

Absorber is an important component in absorption refrigerating system. Its performance plays a significant role on the overall efficiency of absorption refrigerating system. The nanofluids which can enhance the heat and mass transfer will be utilized to absorber for enhancing the water vapor absorption process and improving the absorber efficiency. The software CFD-FLUENT is used to analyze the falling film absorption process of the nanofluids, which consists of H2O/LiBr solution with Fe3O4 nanoparticles in this paper. The results indicate that the enhancing heat and mass transfer of nanofluids is related to the nanoparticle concentration and size. The stronger the nanoparticle concentration, the greater enhancement of heat and mass transfer of falling film; while the smaller the nanoparticle size, the greater enhancement of heat and mass transfer of falling film. It is also found that the enhancement ratio of heat and mass transfer flux reach 1.48 and 1.37, respectively, as the Fe3O4 nanoparticles mass concentration of 0.01wt% and the size of 50nm.

Numerical Simulation of Heat and Mass Transfer Enhancement in Absorption Process With Double-Side Film-Inversion

2008 ◽  
Author(s):  
Ya-Ping Chen ◽  
Chen-Jie Shi ◽  
Ming-Heng Shi ◽  
Chen-Min Ling
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Vertical Plane ◽  
Mathematic Model ◽  
Absorption Process ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Plane Plate ◽  
Before And After ◽  
Calculation Results

Film-inversion is an effective way recently developed to enhance heat and mass transfer in absorbers. However, only one-side of round or rectangular tube i.e. half of the total heat transfer area is used to form film-inverting configuration in the published literature. The paper presents a double-side film-inverting scheme, which consists of two plate bundles and a set of comb shaped conjunction guiders between them for leading solution film from both-sides of each couple of the upper plate bundle to the opposite sides of the bottom ones. A two-scale crosswise corrugation plate bundle, which has vertical large corrugations and horizontal small ones, is suggested instead of the plane plate bundle. The horizontal small corrugation can make the film turbulent and film distribution uniform before and after inversion with surface tension effect, thus increasing the heat and mass transfer coefficients of the absorption process. A mathematic model for heat and mass transfer in absorption process with aqueous Li-Br solution falling film-inverting on two sequential vertical plane plates was established and solved numerically. The distributions of dimensionless velocity, temperature and concentration of liquid film profile before and after film-inverting were obtained. The influence of the number of inversion on heat and mass transfer characteristics was analyzed. The calculation results show that the heat and mass transfer coefficients of the once-film-inverting scheme have about 58% and 73% increment respectively over these of the none film-inverting scheme.

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