scholarly journals Development of an ice-water direct contact heat exchanger in a new district cooling system utilizing ice/water mixture (1st report: Heat transfer characteristics between ice-particle bed and water in a batch-type experiment)

2004 ◽  
Vol 66 (4) ◽  
pp. 463-472
Author(s):  
Yoshitaka KAWADA ◽  
Shuichi YAMADA ◽  
Masataka SHIRAKASHI ◽  
Masaru HATTORI
Keyword(s):  
Heat Transfer ◽  
Direct Contact ◽  
Cooling System ◽  
Water Mixture ◽  
Heat Transfer Characteristics ◽  
Contact Heat ◽  
Batch Type ◽  
Direct Contact Heat Exchanger ◽  
Particle Bed ◽  
Ice Water

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.

Interplay of fluids mixing and heat transfer in a dual-loop ORC direct contact heat exchanger used for waste heat utilization

2020 ◽  
Vol 234 (11) ◽  
pp. 2294-2305
Author(s):  
Qingtai Xiao ◽  
Wen Luo ◽  
Junwei Huang ◽  
Jianxin Xu ◽  
Hua Wang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Transfer Process ◽  
Boiling Heat Transfer ◽  
Direct Contact ◽  
Heat Transfer Process ◽  
Mixing Process ◽  
Contact Heat ◽  
Mixing Index ◽  
Direct Contact Heat Exchanger

By bringing two immiscible fluids at different temperatures into a direct contact heat exchanger (DCHE), bubble swarms are produced in the dual-loop ORC direct contact boiling heat transfer process. The aim of this paper is to make effort to explore the interplay between mixing state quality and heat transfer performance of fluids in the DCHE. Through flow visualization of this mixing process, a simple image analysis technique is introduced to represent the formation and evolution of vapor around the injected coolant droplets. Description of the boiling heat transfer process is here achieved by average volumetric heat transfer coefficient (VHTC). Experimental results attest that the proposed mixing index is powerful and sufficient compared with the Betti numbers method for the mixing quality quantification of bubbles inside DCHE. The synergistic association between the fluids mixing process and the heat transfer process is investigated by statistical regression model of new mixing index and VHTC. The contributions, including the data from monitoring practice in ORC heat transfer system and the proposed way, are presented to delve into the transient behaviors comparison of various fluids mixing and heat transfer processes conveniently.

Droplet Heating in a Direct-Contact Heat Exchanger: Effect of Electric Field

2005 ◽  
Author(s):  
Rajkumar Subramanian ◽  
Milind A. Jog
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Electric Field ◽  
Direct Contact ◽  
Transfer Problem ◽  
Continuous Phase ◽  
Immiscible Fluids ◽  
Contact Heat ◽  
Spherical Droplet ◽  
Direct Contact Heat Exchanger

Heat transfer between two immiscible fluids in a direct contact heat exchanger can be enhanced by the application of an electric field. In this paper, we have numerically modeled heat transfer to a spherical droplet translating in an immiscible medium with an applied electric field. The electric field induces circulatory motion inside and outside the droplet that results in increase in the rate of heat transport. The governing equations for both phases are solved simultaneously by a finite volume method. The external heat transfer problem is considered where the bulk of the resistance is assumed to be in the continuous phase. Effects of electric field strength and translational Reynolds number are investigated.

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