CFD Studies on the Heat Transfer Characteristics of a Horizontal Single-Tube in Fluidized Bed Heat Exchanger

2011 ◽  
Vol 374-377 ◽  
pp. 183-186
Author(s):  
Cong Shen ◽  
Jian Xiang Guo ◽  
Lin Li ◽  
Jin Fei Sun
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Fluidized Bed ◽  
High Performance ◽  
Fluid Model ◽  
Two Phase ◽  
Scaling Properties ◽  
Single Tube ◽  
Industrial Sectors ◽  
Two Fluid Model

The fluidized-bed heat exchanger is widely used in various industrial sectors with the high performance of its heat transfer, ability to adapt working conditions, anti-scaling properties and many other advantages. This paper takes a horizontal single-tube in fluidized-bed heat exchanger and the fluidized low-temperature smoke around the tube as the objects of study. Euler-Euler two-fluid model is taken in use. Heat transfer between gas-solid two-phase flows and water in single-tube is simulated. The temperature field and general heat transfer coefficient is analyzed by simulated graphics.

Numerical Analysis of Heat Transfer and Flow in a Passive Condensation Heat Exchanger

2013 ◽  
Author(s):  
Jong Chull Jo ◽  
Kyu Sik Do ◽  
Yong Kab Lee
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Phase Change ◽  
Fluid Model ◽  
Equilibrium Phase ◽  
Saturated Steam ◽  
Outer Side ◽  
Change Model ◽  
Mass Rate ◽  
Two Fluid Model

A PWR design incorporates a passive auxiliary feedwater system equipped with one passive condensation heat exchanger (PCHX) which consists of inclined V-shaped tube bundles submerged in a water pool of which the top is open to the atmosphere. During the PCHX operation, saturated steam flows into the PCHX where steam is condensed inside of the tubes by cooling the outer side with the pool water. Then, the condensate flows out passively by gravity. Because the thermal-hydraulic characteristics in the PCHX determine the condensation mass rate and the possibility of thermal stratification-induced fatigue of the pool tank wall, system instability and waterhammer, it is important to understand the phase change flow in the PCHX. In this paper, the complex phase change heat transfer and multi-phase flow in a PCHX tube model were numerically simulated. The single fluid multi-component flow model with the equilibrium phase change model was employed for the condensation phase change flow inside the tube and the two-fluid model with the wall boiling model and the equilibrium phase change model was used for the boiling-induced natural convection outside the tube in the pool. Based on the present numerical simulation, the characteristics of the heat transfer and flow in the PCHX are discussed and illustrated for some typical results.

Cavitating Flow of Liquid Nitrogen in Horizontal Rectangular Nozzle

2003 ◽  
Author(s):  
Jun Ishimoto ◽  
Masahiro Onishi ◽  
Takashi Tokumasu ◽  
Kenjiro Kamijo
Keyword(s):  
Liquid Nitrogen ◽  
High Performance ◽  
Fluid Model ◽  
Flow Characteristics ◽  
Cavitating Flow ◽  
Two Phase ◽  
Cloud Cavitation ◽  
Rectangular Nozzle ◽  
Thermodynamic Effect ◽  
Two Fluid Model

The fundamental characteristics of the two-dimensional cavitating flow of liquid nitrogen through a horizontal rectangular nozzle are numerically and experimentally investigated to realize the further development and high performance of new multiphase cryogenic fluid applications. First, the governing equations of the cavitating flow of liquid nitrogen based on the unsteady thermal nonequilibrium two-fluid model are presented, and several flow characteristics are numerically calculated, taken into account the thermodynamic effect of cryogenic conditions. Next, the flow visualization measurement on unsteady cavitating flow of liquid nitrogen through a rectangular nozzle installed in a horizontal duct is carried out to clarify the basic cryogenic two-phase flow structure and fundamental characteristics of the transient growth process of cryogenic cloud cavitation.

Bubbling Flow in a Multi-Jet Fluidized Bed

2020 ◽  
Author(s):  
Liwu Wang ◽  
Sijun Zhang
Keyword(s):  
Fluidized Bed ◽  
Fluidized Beds ◽  
Fluid Model ◽  
Bubble Formation ◽  
Model Parameters ◽  
Phase Flow ◽  
Two Phase ◽  
Single Jet ◽  
Two Fluid Model ◽  
Two Fluid

Abstract This work concerns with numerical simulation of dense gas-particle two-phase flow in a fluidized bed in the framework of two-fluid model, where attention is given to the bubble formation in a single-jet and multi-jet fluidized beds. The kinetic theory is implemented in the model to avoid empirically determined model parameters. The validity of the approach is confirmed through the comparison between the computed results and the measurements in the literature. The results show that increasing the number of jets results in different behavior in bubble formation and the flow pattern in a multi-jet bed is much more complex than that in a single-jet bed.

scholarly journals Natural modes of the two-fluid model of two-phase flow

2021 ◽  
Vol 33 (3) ◽  
pp. 033324
Author(s):  
Alejandro Clausse ◽  
Martín López de Bertodano
Keyword(s):  
Two Phase Flow ◽  
Fluid Model ◽  
Phase Flow ◽  
Two Phase ◽  
Natural Modes ◽  
Two Fluid Model ◽  
Two Fluid
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