Direct contact heat transfer with change of phase: Effect of the initial drop size in three-phase heat exchangers

AIChE Journal ◽  
1965 ◽  
Vol 11 (6) ◽  
pp. 1081-1087 ◽  
Author(s):  
Samuel Sideman ◽  
Gideon Hirsch ◽  
Yehuda Gat
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Direct Contact ◽  
Drop Size ◽  
Phase Effect ◽  
Contact Heat ◽  
Contact Heat Transfer ◽  
Three Phase ◽  
Initial Drop

Direct-Contact Heat Transfer for Air Bubbling Through Water

1991 ◽  
Vol 113 (2) ◽  
pp. 71-74 ◽  
Author(s):  
H. S. Ghazi
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Heat Transfer Coefficient ◽  
Constant Temperature ◽  
Heat Exchangers ◽  
Direct Contact ◽  
Contact Heat ◽  
Overall Heat Transfer Coefficient ◽  
Contact Heat Transfer ◽  
Closed Type

Experiments on direct-contact heat transfer of air injected through an orifice and bubbling through a constant temperature, stagnant, pool of water showed an increase in air temperature ranging from about 100 to 200 percent. The process follows a relationship which describes heat transfer in conventional, closed-type, heat exchangers where one fluid is maintained at a constant temperature. The data is correlated by a relationship for the Nusselt number which is based on an average overall heat transfer coefficient.

scholarly journals Analytical Modelling of a Spray Column Three-Phase Direct Contact Heat Exchanger

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hameed B. Mahood ◽  
Adel O. Sharif ◽  
Seyed Ali Hosseini ◽  
Rex B. Thorpe
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Direct Contact ◽  
Relative Velocity ◽  
Contact Heat ◽  
Spray Column ◽  
Three Phase ◽  
Direct Contact Heat Exchanger

An analytical model for the temperature distribution of a spray column, three-phase direct contact heat exchanger is developed. So far there were only numerical models available for this process; however to understand the dynamic behaviour of these systems, characteristic models are required. In this work, using cell model configuration and irrotational potential flow approximation characteristic models has been developed for the relative velocity and the drag coefficient of the evaporation swarm of drops in an immiscible liquid, using a convective heat transfer coefficient of those drops included the drop interaction effect, which derived by authors already. Moreover, one-dimensional energy equation was formulated involving the direct contact heat transfer coefficient, the holdup ratio, the drop radius, the relative velocity, and the physical phases properties. In addition, time-dependent drops sizes were taken into account as a function of vaporization ratio inside the drops, while a constant holdup ratio along the column was assumed. Furthermore, the model correlated well against experimental data.

Increasing efficiency in direct contact heat transfer

1987 ◽  
Vol 6 (4) ◽  
pp. 208-210 ◽  
Author(s):  
Ralph F. Strigle ◽  
Tsuneo Nakano
Keyword(s):  
Heat Transfer ◽  
Direct Contact ◽  
Contact Heat ◽  
Contact Heat Transfer

An Analysis of a Direct Contact Ice Slurry Generator

2008 ◽  
Author(s):  
M. A. Wahed ◽  
M. N. A. Hawlader
Keyword(s):  
Heat Transfer ◽  
Simulation Model ◽  
Direct Contact ◽  
Coolant Flow ◽  
Temperature Profiles ◽  
Ice Slurry ◽  
Generation System ◽  
Contact Heat ◽  
Flow Rates ◽  
Contact Heat Transfer

Attempts have been made to study an ice slurry generation system where two immiscible liquids, water and a coolant, are used to produce ice slurry by direct contact heat transfer. A mathematical model has been developed to evaluate the heat transfer phenomena between the coolant drops and the water in the ice slurry generation system. In this process, all the important variables that affect the direct contact heat transfer between these two fluids were incorporated into the simulation model to evaluate thermal performance of the system. Experiments were performed on an ice slurry generator using water and an immiscible liquid coolant, Fluroinert FC-84. The coolant at about −10°C to −15°C was delivered to the top of the ice slurry generator containing water and collected from the bottom for recirculation. The measured temperature profiles of water in the ice slurry generator for different coolant flow rates (8 lit/min to 12 lit/min) showed a good agreement with those temperature profiles obtained from the simulation model. These results validated the simulation model developed for the ice slurry generator. The analysis showed that during sensible cooling, the estimated heat transfer coefficients between water and the coolant were in the range of 3.0 to 6.5 kW/m2 for coolant flow rates varying from 8 lit/min to 12 lit/min. Higher coolant flow rates also enhanced the ice formation process due to the increased heat transfer rate. In addition, it was also observed that the ice production increased significantly when the nozzle was placed at the bottom of the ice slurry generator.

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