Heat transfer analysis of pasteurization of bottled beer in a tunnel pasteurizer using computational fluid dynamics

2014 ◽  
Vol 23 ◽  
pp. 156-163 ◽  
Author(s):  
E. Bhuvaneswari ◽  
C. Anandharamakrishnan
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Transfer Analysis

Computational Fluid Dynamics and Heat Transfer Analysis for a Novel Heat Exchanger

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Haolin Ma ◽  
Dennis E. Oztekin ◽  
Seyfettin Bayraktar ◽  
Sedat Yayla ◽  
Alparslan Oztekin
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Exchanger ◽  
Turbulent Flows ◽  
Flow Structure ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Heat Transfer Analysis ◽  
Two Dimensional

Computational fluid dynamics (CFD) and heat transfer simulations are conducted for a novel heat exchanger. The heat exchanger consists of semi-circle cross-sectioned tubes that create narrow slots oriented in the streamwise direction. Numerical simulations are conducted for Reynolds numbers (Re) ranging from 700 to 30,000. Three-dimensional turbulent flows and heat transfer characteristics in the tube bank region are modeled by the k-ε Reynolds-averaged Navier–Stokes (RANS) method. The flow structure predicted by the two-dimensional and three-dimensional simulations is compared against that observed by the particle image velocimetry (PIV) for Re of 1500 and 4000. The adequate agreement between the predicted and observed flow characteristics validates the numerical method and the turbulent model employed here. The three-dimensional and the two-dimensional steady flow simulations are compared to determine the effects of the wall on the flow structure. The wall influences the spatial structure of the vortices formed in the wake of the tubes and near the exit of the slots. The heat transfer coefficient of the slotted tubes improved by more than 40% compare to the traditional nonslotted tubes.

Computational Fluid Dynamics and Heat Transfer Analysis of Vortex Formation in a Solar Reactor

2015 ◽  
Vol 7 (4) ◽  
Author(s):  
Min-Hsiu Chien ◽  
Nesrin Ozalp ◽  
Gerald Morrison
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Room Temperature ◽  
Vortex Flow ◽  
Vortex Formation ◽  
Flow Dynamics ◽  
Experimental Results ◽  
Heat Transfer Analysis ◽  
Solar Reactor

A hydrogen-producing solar reactor was experimentally tested to study the cyclone flow dynamics of the gas–particle two-phase phenomenon. Two-dimensional particle image velocimetry (PIV) was used to observe the flow and to quantify the vortex formation inside the solar reactor. The vortex flow structure in the reactor was reconstructed by capturing images from orientations perpendicular and parallel to the geometrical axis of the reactor, respectively. The experimental results showed that the tangential components of the fluid velocity formed a Rankine-vortex profile. The free vortex portions of the Rankine profile were synchronized and independent of the axial position. The axial components showed a vortex funnel of higher speed fluid supplied by a reversing secondary flow. According to the inlet channel design, the geometry dominates the flow dynamics. A stable processing vortex line was observed. As the vortex flow evolves toward the exit, the vortex funnel expands radially with decreasing tangential velocity magnitude peak as a result of the vortex stretching. An optimal residence time of the flow was found by changing the cyclone flow inlet conditions. The swirl number versus the main flow rate change was obtained. Upon completion of the experimental studies, a thorough numerical analysis was conducted to model the flow dynamics inside the solar reactor and to verify the results by comparison to the experimental results. Three turbulence models including the standard k–ϵ, k–ϵ renormalization groups (RNG), and Reynolds stress transport models were used. Computational fluid dynamics (CFD) simulations were coupled with heat transfer analysis via discrete ordinate (DO) model. Particle tracing in Lagrange frame was applied to simulate the particle trajectory. A comparison between the turbulence modeling results for the room temperature and high temperature cases, as well as the experimental results for room temperature cases is presented.

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