Open AccessAFFECTING PARAMETERS TO THE HEAT AND MASS TRANSFER OF NH3-H2O SOLUTION FALLING ON THE HORIZONTAL ROUND TUBE
Author(s) -
Nguyen Hieu Nghia,
Le Chi Hiep,
Cong-Truyen Duong
Publication year - 2021
Publication title -
khoa học và công nghệ
Language(s) - English
Resource type - Journals
ISSN - 2525-2267
DOI - 10.46242/jst-iuh.v45i01.1019
Subject(s) - heat transfer coefficient , thermodynamics , mechanics , heat transfer , mass transfer , mass transfer coefficient , materials science , absorption refrigerator , tube (container) , absorption (acoustics) , refrigeration , composite material , physics
The absorption process has been confirmed as the most important process in absorption refrigeration machines in terms of improving their total efficiency. One of the key research directions is the selection of absorber structure which is expected to be fabricated in Vietnam without demand of new infrastructure investment. In this study, a local model of the coupled heat and mass transfer during absorption process of NH3 vapor by a NH3-H2O diluted solution flowing over horizontal round tubes of an absorber was made. The heat transfer coefficient obtained from the coupled heat and mass transfer mathematic model. This heat transfer coefficient is used to calculate the variation of the simulated value of heat load. The correlations which give the heat transfer coefficient and mass transfer coefficient in the absorption process in range of solution concentration ω = 28% ÷ 31%, solution mass flow rate per unit tube length Γ = 0.001 ÷ 0.03 kgm-1s-1, coolant temperature twater = 28 oC ÷ 38 oC are set as two functions. The practical decrease of wetted ratio analyses were taken into account when the solution flow from the top to the bottom of the parallel tube bundle. The deviation of theoretical heat load and experimental heat load is about 12.3%. Based on these simulations, the theoretical studies were done for absorption refrigeration system in order to narrow the working area where the experiments later focused on. The results of this study will be the basis for subsequent application research of falling film absorbers.