Heat and mass transfer analysis of a wavy fin-and-tube heat exchanger under fully and partially wet surface conditions

2010 ◽  
Vol 49 (2) ◽  
pp. 349-355 ◽  
Author(s):  
Ralf Wiksten ◽  
M. El Haj Assad
Keyword(s):  
Mass Transfer ◽  
Heat Exchanger ◽  
Heat And Mass Transfer ◽  
Surface Conditions ◽  
Tube Heat Exchanger ◽  
Wet Surface

A Fully Wet and Fully Dry Tiny Circular Fin Method for Heat and Mass Transfer Characteristics for Plain Fin-and-Tube Heat Exchangers Under Dehumidifying Conditions

2006 ◽  
Vol 129 (9) ◽  
pp. 1256-1267 ◽  
Author(s):  
Worachest Pirompugd ◽  
Chi-Chuan Wang ◽  
Somchai Wongwises
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Exchanger ◽  
Heat And Mass Transfer ◽  
Heat Exchangers ◽  
Heat Transfer Characteristic ◽  
Transfer Characteristic ◽  
Tube Heat Exchanger ◽  
Mass Transfer Characteristic ◽  
Transfer Characteristics

This study proposes a new method, namely the “fully wet and fully dry tiny circular fin method,” for analyzing the heat and mass transfer characteristics of plain fin-and-tube heat exchangers under dehumidifying conditions. The present method is developed from the tube-by-tube method proposed in the previous study by the same authors. The analysis of the fin-and-tube heat exchangers is carried out by dividing the heat exchanger into many tiny segments. A tiny segment will be assumed with fully wet or fully dry conditions. This method is capable of handling the plain fin-and-tube heat exchanger under fully wet and partially wet conditions. The heat and mass transfer characteristics are presented in dimensionless terms. The ratio of the heat transfer characteristic to mass transfer characteristic is also studied. Based on the reduced results, it is found that the heat transfer and mass transfer characteristics are insensitive to changes in fin spacing. The influence of the inlet relative humidity on the heat transfer characteristic is rather small. For one and two row configurations, a considerable increase of the mass transfer characteristic is encountered when partially wet conditions take place. The heat transfer characteristic is about the same in fully wet and partially wet conditions provided that the number of tube rows is equal to or greater than four. Correlations are proposed to describe the heat and mass characteristics for the present plain fin configuration.

Analysis of Influences of Soil Characteristics on the Underground Heat Exchanger With a Novel Heat and Mass Transfer Model

2010 ◽  
Author(s):  
Sufen Li ◽  
Haijun Li ◽  
Jinxiang Wang ◽  
Yan Shang ◽  
Lanhua Dai ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Temperature Field ◽  
Heat Exchanger ◽  
Heat And Mass Transfer ◽  
Energy Equation ◽  
Seepage Flow ◽  
Heat Transfer Process ◽  
Transfer Model ◽  
Mass Transfer Model ◽  
Tube Heat Exchanger

In this paper, a novel heat and mass transfer model was used to simulate the temperature field of both the U-tube heat exchanger and soil around it. Beside two-dimensional N-S equations were solved to consider the seepage of groundwater, an energy equation coupling thermal conduction and groundwater advection was enclosed in the model as well. The energy equation was built according to the real conditions of the U-tube and seepage flow in the soil. Through analyzing the simulation results, the effects of groundwater seepage to the heat transfer process and thermal short-circuiting among U-tube legs are obtained. The influences of soil type, soil physical aspects and backfill on the soil temperature field around the single U-tube of an underground heat exchanger were studied at the same time. The conclusions had great academic significance to the analysis and designing of the underground heat exchanger.

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