Modeling of radiative heat transfer and mass transfer processes in drop-flow-based heat exchangers for spacecraft

1998 ◽  
Vol 71 (1) ◽  
pp. 87-91
Author(s):  
G. V. Konyukhov ◽  
A. A. Koroteev ◽  
V. V. Novomlinskii ◽  
B. N. Baushev
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Radiative Heat Transfer ◽  
Heat Exchangers ◽  
Radiative Heat ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Drop Flow

Research Needs: Industrial Spray Processes, Spray Drying, and Heat Transfer

1988 ◽  
Vol 41 (10) ◽  
pp. 365-370 ◽  
Author(s):  
William S. Janna
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
High Pressure ◽  
Spray Drying ◽  
Research Needs ◽  
Comprehensive Model ◽  
Research Topics ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Enhance Mass

A survey of researchers and of manufacturers of spraying, drying, and spray heat transfer equipment was conducted. Those that responded provided descriptions of processes and devices that need developmental attention. Several of these problems are described here (eg, a unifying theory of how atomization takes place; a method of evaluating the performance of a spray used to dissolve air in water to enhance mass transfer processes; a comprehensive model for predicting heat transfer from high pressure sprays; etc). It is concluded that many research topics can be gleaned from industry as needs develop and innovative ways are found for sprays to replace conventional methods.

Heat and Mass Transfer Processes and the Performance Evaluation in Single-Slope Solar Stills

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
David A. Aderibigbe
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat And Mass Transfer ◽  
Glass Cover ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Basin Water ◽  
The Heat Transfer Coefficient

The paper reviews the present understanding of the analysis of the heat and mass transfer processes in single-slope solar stills. By using the results of published experiments, it is proposed that the heat and mass transfer phenomena from the basin water to the glass cover are coupled. This coupling makes it possible to derive the dependence of the heat transfer coefficient for condensation on the inclination of the glass cover of the still. The derived relation, i.e., Nucon = 0.738 (Grcon*Prcon*sin β/Ja*)¼ A−1 where A is the aspect ratio, has been demonstrated to be an important expression for predicting the heat transfer coefficient for condensation hcon necessary for a more realistic evaluation of the overall efficiency of single-slope solar still of a given cover angle β.

scholarly journals RANDOMIZATION OF EXPERIMENTS IN CHEMICAL TECHNOLOGY

2021 ◽  
Vol 1 (1) ◽  
pp. 5-6
Author(s):  
Aleksey Bal'chugov
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Chemical Technology ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Experi Mental Study

It is shown that randomization allows obtaining more reliable results in the experi mental study of hydrodynamic, heat transfer and mass transfer processes.

scholarly journals Numerical Investigation of Natural Convective Condensation with Noncondensable Gases in the Reactor Containment after Severe Accidents

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Wen Fu ◽  
Li Zhang ◽  
Xiaowei Li ◽  
Xinxin Wu
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Mass Fraction ◽  
Transfer Processes ◽  
Noncondensable Gases ◽  
Mass Transfer Processes ◽  
Convective Condensation

The heat and mass transfer processes of natural convective condensation with noncondensable gases are very important for the passive containment cooling system of water cooled reactors. Numerical simulation of natural convective condensation with noncondensable gases was realized in the Fluent software by adding condensation models. The scaled AP600 containment condensation experiment was simulated to verify the numerical method. It was shown that the developed method can predict natural convective condensation with noncondensable gases well. The velocity, species, and density fields in the scaled AP600 containment were presented. The heat transfer rate distribution and the influences of the mass fraction of air on heat transfer rate were also analyzed. It is found that the driving force of natural convective condensation with noncondensable gases is mainly caused by the mass fraction difference but not temperature difference. The natural convective condensation with noncondensable gases in AP1000 containment was then simulated. The temperature, species, velocity, and heat flux distributions were obtained and analyzed. The upper head of the containment contributes to 35.1% of the total heat transfer rate, while its area only takes 25.4% of the total condensation area of the containment. The influences of the mass fraction of low molecular weight noncondensable gas (hydrogen) on the natural convective condensation were also discussed based on the detailed species, density, and velocity fields. The results show that addition of hydrogen (production of zirconium-water reaction after severe accident) will weaken the intensity of natural convection and the heat and mass transfer processes significantly. When hydrogen contributes to 50% mole fraction of the noncondensable gases, the heat transfer coefficient will be reduced to 45%.

scholarly journals The influence of airflow on the effectiveness of rotary heat exchangers operating under high-speed rotor conditions

2019 ◽  
Vol 116 ◽  
pp. 00032
Author(s):  
Paulina Kanaś ◽  
Andrzej Jedlikowski ◽  
Sergey Anisimov ◽  
Borys Vager
Keyword(s):  
Mass Transfer ◽  
Heat Exchanger ◽  
Heat And Mass Transfer ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
High Speed ◽  
Airflow Rate ◽  
Sharp Drop ◽  
Transfer Processes ◽  
Mass Transfer Processes

The paper presents an analysis of heat and mass transfer processes occurring inside the rotary heat exchanger operating under high-speed rotor conditions for different values of the airflow rate. For this purpose the original mathematical α-model was used. Conducted computer simulations allowed to determine the influence of Number of Transfer Units (NTU) of airflow on the temperature effectiveness as well as on the distribution of different active heat and mass transfer zones: “dry”, “wet” and “frost”. It was found that the increase of the values of NTU strictly affects the increase of the effectiveness of heat recovery. Another issue emerging from this study is the fact that in the certain range of low values of NTU there is no “dry” area created. It was established that at low values of NTU (NTU≈1) “frost” area extremum and sharp drop in the “frost” area accumulation are observed.

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