Heat and mass transfer characteristics of a horizontal tube falling film absorber with small diameter tubes

2007 ◽  
Vol 44 (4) ◽  
pp. 437-444 ◽  
Author(s):  
Jung-In Yoon ◽  
Thanh Tong Phan ◽  
Choon-Geun Moon ◽  
Ho-Saeng Lee ◽  
Seok-Kwon Jeong
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Small Diameter ◽  
Horizontal Tube ◽  
Falling Film ◽  
Transfer Characteristics

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.

Falling-Film Absorption Around Microchannel Tube Banks

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
Ananda Krishna Nagavarapu ◽  
Srinivas Garimella
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Water Solution ◽  
Small Diameter ◽  
Operating Conditions ◽  
Test Facility ◽  
Vapor Flow ◽  
Falling Film ◽  
Flow Rates ◽  
Wide Range

An experimental investigation of heat and mass transfer in a falling-film absorber with microchannel tube arrays was conducted. Liquid ammonia–water solution flows in a falling-film mode around an array of small diameter coolant tubes, while vapor flows upward through the tube array counter-current to the falling film. This absorber was installed in a test facility consisting of all components of a functional single-effect absorption chiller, including a desorber, rectifier, condenser, evaporator, solution heat exchanger, and refrigerant precooler, to obtain realistic operating conditions at the absorber and to account for the influence of the other components in the system. Unlike studies in the literature on bench-top, single-component, single-pressure test stands, here the experiments were conducted on the absorber at vapor, solution, and coupling fluid conditions representative of space-conditioning systems in the heating and cooling modes. Absorption measurements were taken over a wide range of solution flow rates, concentrations, and coupling fluid temperatures, which simulated operation of thermally activated absorption systems at different cooling capacities and ambient conditions. These measurements are used to interpret the effects of solution and vapor flow rates, concentrations, and coupling fluid conditions on the respective heat and mass transfer coefficients.

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