Heat and mass transfer simulation of the human airway for nano-particle water vapor

2016 ◽  
Vol 23 (6) ◽  
pp. 33-39
Author(s):  
Masoud Khajenoori ◽  
Ali Haghighi Asl
Keyword(s):  
Mass Transfer ◽  
Water Vapor ◽  
Heat And Mass Transfer ◽  
Nano Particle ◽  
Human Airway

Effects of a Nonabsorbable Gas on Interfacial Heat and Mass Transfer for the Entrance Region of a Falling Film Absorber

1996 ◽  
Vol 118 (1) ◽  
pp. 45-49 ◽  
Author(s):  
T. A. Ameel ◽  
H. M. Habib ◽  
B. D. Wood
Keyword(s):  
Mass Transfer ◽  
Water Vapor ◽  
Analytical Solution ◽  
Liquid Film ◽  
Heat And Mass Transfer ◽  
Vertical Wall ◽  
Lithium Bromide ◽  
Entrance Region ◽  
Falling Film ◽  
Aqueous Lithium Bromide

An analytical solution is presented for the effect of air (nonabsorbable gas) on the heat and mass transfer rates during the absorption of water vapor (absorbate) by a falling laminar film of aqueous lithium bromide (absorbent), an important process in a proposed open-cycle solar absorption cooling system. The analysis was restricted to the entrance region where an analytical solution is possible. The model consists of a falling film of aqueous lithium bromide flowing down a vertical wall which is kept at uniform temperature. The liquid film is in contact with a gas consisting of a mixture of water vapor and air. The gas phase is moving under the influence of the drag from the falling liquid film. The governing equations are written with a set of interfacial and boundary conditions and solved analytically for the two phases. Heat and mass transfer results are presented for a range of uniform inlet air concentrations. It was found that the concentration of the nonabsorbable gas increases sharply at the liquid gas interface. The absorption of the absorbate in the entrance region showed a continuous reduction with an increase in the amount of air.

Heat and Mass Transfer Characteristics in Adsorption of Water Vapor for Silica Gel Packed Bed Adsorber.

2000 ◽  
Vol 33 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Eri Yamamoto ◽  
Koichi Katsurayama ◽  
Fujio Watanabe ◽  
Hitoki Matsuda ◽  
Masanobu Hasatani
Keyword(s):  
Mass Transfer ◽  
Water Vapor ◽  
Heat And Mass Transfer ◽  
Silica Gel ◽  
Packed Bed ◽  
Transfer Characteristics ◽  
Adsorption Of Water ◽  
Adsorption Of Water Vapor

scholarly journals Heat and mass transfer in the grain under variable conditions

2021 ◽  
pp. 84-87
Author(s):  
Mikhail Gennadievich Zagoruiko ◽  
Roman Aleksandrovich Marin
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Water Vapor ◽  
Heat And Mass Transfer ◽  
Internal Heat ◽  
Initial Moment ◽  
Dense Layer ◽  
Drying Process ◽  
Grain Moisture ◽  
Grain Surface

The article describes the drying process in the formulation of the internal problem, the main equations of internal heat and mass transfer of potentials are considered. The process of removing moisture from the surface of the grain, which is determined by the transfer of moisture and the diffusion-convective transfer of heat and moisture through the boundary layer, is studied. The movement of heat in the boundary layer was determined by the molecular thermal conductivity. It is established that the speed of the drying process depends on the rate of removal of water vapor from the surface of the grain. It was found that the change in the quality of the seed material did not depend on the absolute removal of moisture. The first drying period is shown, when the temperature of the grain surface rises from the temperature of the adiabatic air saturation, when the drying agent at the boundary of the grain surface is saturated with water vapor, and the drying speed depends on the speed of their removal from the evaporation surface. At this point, the moisture evaporated, the vapors were removed by the drying agent. At the initial moment, the movement of the evaporation line did not occur, but then it was fixed inside the grain. In the course of research, the process of removing moisture from the seeds is fast, but it has little effect on their quality. The removal of grain moisture reached up to 3 % from the upper layers of the seeds, which did not affect their quality. An analytical expression is considered for calculating the heat transfer coefficient and the drying agent velocity, taking into account the allowed moisture content, as well as the heat flux density. The permissible speed of the drying agent in a dense layer of grain is determined, which depends on the height of the layer, the specific surface of the grain, its temperature and the proportion of heat supplied to heat the material. For drying conditions typical for grain dryers, the drying speed should not exceed 0.6 m/s.

Intraparticle Heat and Mass Transfer Characteristics of Water Vapor Adsorption

2002 ◽  
Vol 35 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Eri Yamamoto ◽  
Fujio Watanabe ◽  
Noriyuki Kobayashi ◽  
Masanobu Hasatani
Keyword(s):  
Mass Transfer ◽  
Water Vapor ◽  
Heat And Mass Transfer ◽  
Water Vapor Adsorption ◽  
Vapor Adsorption ◽  
Transfer Characteristics

Numerical Simulations of Heat and Mass Transfer in Condensing Heat Exchangers for Water Recovery in Power Plants

2011 ◽  
Author(s):  
Kwangkook Jeong ◽  
Harun Bilirgen ◽  
Edward Levy
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Water Vapor ◽  
Sulfuric Acid ◽  
Heat Exchanger ◽  
Power Plant ◽  
Heat And Mass Transfer ◽  
Flue Gas ◽  
Cooling Water ◽  
Condensing Heat Exchanger

Power plants release a large amount of water vapor into the atmosphere through the stack. The flue gas can be a potential source for obtaining much needed cooling water for a power plant. If a power plant could recover and reuse a portion of this moisture, it could reduce its total cooling water intake requirement. One of the most practical way to recover water from flue gas is to use a condensing heat exchanger. The power plant could also recover latent heat due to condensation as well as sensible heat due to lowering the flue gas exit temperature. Additionally, harmful acids released from the stack can be reduced in a condensing heat exchanger by acid condensation. Condensation of vapors in flue gas is a complicated phenomenon since heat and mass transfer of water vapor and various acids simultaneously occur in the presence of non-condensable gases such as nitrogen and oxygen. Design of a condenser depends on the knowledge and understanding of the heat and mass transfer processes. A computer program for numerical simulations of water (H2O) and sulfuric acid (H2SO4) condensation in a flue gas condensing heat exchanger was developed using MATLAB. Governing equations based on mass and energy balances for the system were derived to predict variables such as flue gas exit temperature, cooling water outlet temperature, mole fraction and condensation rates of water and sulfuric acid vapors. The equations were solved using an iterative solution technique with calculations of heat and mass transfer coefficients and physical properties. An experimental study was carried out in order to yield data for validation of modeling results. Parametric studies for both modeling and experiments were performed to investigate the effects of parameters such as flue gas flow rate, cooling water flow rate, inlet cooling water temperature and tube configurations (bare and finned tubes) on condensation efficiency. Predicted results of water and sulfuric acid vapor condensation were compared with experimental data for model validation, and this showed agreement between experimental data and predictions to within a few percent. The most important parameters affecting performance of the condensing heat exchangers was the ratio of cooling water to flue gas flow rates, since this determines how much heat the cooling water can absorb. The computer program simultaneously calculates both water vapor condensation and sulfuric acid condensation in flue gas along downstream. Modeling results for prediction of sulfuric acid vapor concentration in the flue gas were compared with measured data obtained by the controlled condensation method. An analytical model of sulfuric acid condensation for oil-firing showed two trends — steep reduction within the high temperature heat exchanger and smooth reduction within lower temperature heat exchanger, which is in agreement with experimental data.

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