A Parametric Study of a Particulate Direct Contact Heat Exchanger

1981 ◽  
Vol 103 (3) ◽  
pp. 586-590 ◽  
Author(s):  
Ruth Letan

The function performed by a direct contact heat exchanger is by definition a heat interaction between two media without an interfering wall between them. The direct contact heat exchanger analyzed herein refers to the restricted definition of systems in which temperatures of the contacted media vary without change of phase. This class involves the particulate systems of immiscible liquids, solid particles in fluids, gas bubbles in liquids, and droplets in gases. The applicability of direct contact heat exchangers has been considered for use in fouling and crystallizing systems, sea-water heating, geothermal brines, as well as in nuclear and MHD power plants. An analytic way to evaluate the performance of a direct contact heat exchanger is applied to examine the effects of operational variables upon length and diameter of a heat exchanger. The heat exchanger becomes shorter as the particle size decreases, and heat capacity ratio, flow rate ratio and approach temperature increase. The diameter of the column decreases with the particle size, and the density ratio of the contacted media. It increases with the flow rate ratio. All the evaluations made, correspond to the laminar bulk flow in the heat exchanger, and to particle Reynolds numbers in the range of 20–500.

2019 ◽  
Vol 147 ◽  
pp. 592-601 ◽  
Author(s):  
Jianxin Xu ◽  
Qingtai Xiao ◽  
Zhihan Lv ◽  
Junwei Huang ◽  
Ruoxiu Xiao ◽  
...  

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hameed B. Mahood ◽  
Adel O. Sharif ◽  
Seyed Ali Hosseini ◽  
Rex B. Thorpe

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.


2001 ◽  
Vol 30 (2) ◽  
pp. 95-113
Author(s):  
Akiyoshi Ohira ◽  
Michio Yanadori ◽  
Kunihiko Iwabuchi ◽  
Toshikatsu Kimura ◽  
Yuji Tsubota

KSME Journal ◽  
1995 ◽  
Vol 9 (1) ◽  
pp. 19-28 ◽  
Author(s):  
In Seak Kang ◽  
Chong Bo Kim ◽  
Won Gee Chun

1981 ◽  
Vol 103 (2) ◽  
pp. 128-132 ◽  
Author(s):  
C. A. Kodres ◽  
H. R. Jacobs ◽  
R. F. Boehm

An explicit procedure for analyzing a superheated, evaporating lens direct contact heat exchanger has been developed. This method is based upon the application of a dimensional analysis derivation of a relationship for the heat flux from a single evaporating lens. Several suggestions are offered for use in the design of these devices. To estimate the error introduced by extrapolating a single lens model to represent a system of lenses, the method is used to “design” two operating geothermal heat exchangers. A difference of about 16 percent is observed between the calculated and measured overall heat flux.


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