Predicting Hydrodynamic and Heat Transfer Effects of Sparger Geometry and Placement Within a Column Photobioreactor Using Computational Fluid Dynamics

2014 ◽  
Vol 11 (3) ◽  
Author(s):  
Ghazi S. Bari ◽  
Taylor N. Suess ◽  
Gary A. Anderson ◽  
Stephen P. Gent

This research investigates the effects of the sparger on flow patterns and heat transfer within a column photobioreactor (PBR) using computational fluid dynamics (CFD). This study compares two types of spargers: a porous membrane, which occupies the entire floor of the reactor, and a single sparger, which is located along the centerline of the PBR floor. The PBR is modeled using the Lagrangian–Eulerian approach. The objective of this research is to predict the performance of PBRs using CFD models, which can be used to improve the design of PBRs used to grow microalgae that are used to produce biofuels and bioproducts.

Author(s):  
Ghazi S. Bari ◽  
Stephen P. Gent ◽  
Taylor N. Suess ◽  
Gary A. Anderson

An important factor in designing photobioreactors is appropriate selection of sparger geometry and placement. The sparger governs the bubble size distribution and gas hold-up. These factors in turn influence flow pattern, effective interfacial area, rates of mass transfer, heat transfer, and mixing. This project investigates the effects of sparger geometry and placement on bubble and fluid flow patterns and convective heat transfer within a column photobioreactor (PBR) using Computational Fluid Dynamics (CFD). Experimental and computational studies have been completed that focused on the hydrodynamics and heat transfer within a rectangular column photobioreactor (34.29 cm long × 15.25 cm wide × 34.29 cm tall) with a single sparger located at the center of its base (33.02 cm × 1.27 cm) running lengthwise. Similar studies have also been completed analyzing a full width sparger on the bottom of the PBR similar to a porous membrane sparger. This study extends previous work by investigating the flow patterns and heat transfer effects due to multiple rows of spargers at different spacings running perpendicular to the length of the PBR. Comparison of hydrodynamic and heat transfer parameters are made for the different types of spargers at different volumetric flow rates. The gas bubbles and the water-based media within the photobioreactor are modeled using the Lagrangian-Eulerian approach. A low Reynolds k-Epsilon turbulence model is used to predict near-wall flow patterns. The main interaction forces between the bubbles and the media, including drag forces, added mass forces, and lift forces, are considered. The overarching goal of this research is to improve PBR designs, thus enhancing microalgae production for biofuel and bioproducts production. It is hypothesized that changing the spacing of the PBR spargers will alter the bubble flow patterns. Despite its importance, optimizing the sparger geometry and placement in PBRs for microalgae production is still largely not understood. In this study, simulation results are presented for various sparger spacings, which can be helpful in designing sparger geometry and placement for maximized microalgae production.


2015 ◽  
Vol 12 (1) ◽  
Author(s):  
Ghazi S. Bari ◽  
Taylor N. Suess ◽  
Gary A. Anderson ◽  
Stephen P. Gent

This research investigates the placement of spargers on thermofluid effects within a column photobioreactor (PBR) using computational fluid dynamics (CFD). This study compares two configurations, each with three rows of spargers spaced at different widths: one with spargers spaced 7.62 cm apart and the other spaced 10.16 cm apart. These spargers are modeled in a PBR with overall dimensions of 34.29 cm in length, 15.25 cm in width, and 34.28 cm in height. The objective of this research is to predict the performance of PBRs using CFD, which can be used to improve the design of PBRs used to grow microalgae for biofuels and bioproducts.


Author(s):  
Ghazi S. Bari ◽  
Stephen P. Gent ◽  
Taylor N. Suess ◽  
Gary A. Anderson

This project investigates the effects of sparger geometry and placement on bubble and fluid flow patterns and convective heat transfer within a column photobioreactor (PBR) using Computational Fluid Dynamics (CFD). Experimental and computational studies have been completed that focused on the hydrodynamics and heat transfer within a rectangular column photobioreactor (34.29 cm long × 15.25 cm wide × 34.29 cm tall) with a single sparger located at the center of its base (33.02 cm × 1.27 cm) running lengthwise. This study extends previous work by investigating the flow patterns and heat transfer effects due to full bottom sparger or porous sparger. The gas bubbles and the water-based media within the photobioreactor are modeled using the Lagrangian-Eulerian approach. A low Reynolds k-Epsilon turbulence model is used to predict near-wall flow patterns. A flat surface photobioreactor is used to achieve sufficient light penetration into the system. The main interaction forces between the bubbles and the media, including drag forces, added mass forces, and lift forces are considered. The overarching goal of this research is to produce biofuels and bioproducts through the improved design of column PBRs used for microalgae production. An important factor in designing photobioreactors is the appropriate selection of sparger geometry and placement. The sparger governs the bubble size distribution and gas holdup. These factors in turn influence flow pattern, effective interfacial area, rates of mass transfer, heat transfer, and mixing. It is hypothesized that increasing the sparger width will improve uniformity of bubble distribution as well as mixing. Despite its importance, optimizing the sparger geometry and placement in PBRs for microalgae production is still largely not understood. In this study, the simulation’s results are presented for various spargers, which can be helpful in designing appropriate sparger geometry and proper placement for increased microalgae production.


Author(s):  
Arezoo Berenjforoush Azar ◽  
Yousef Ramezan ◽  
Morteza Khashehchi

AbstractIn this study, conductive heat transfer was investigated during sterilization in the canned celery stew. A computational fluid dynamics CFD model was developed and validated to predict the temperature profiles and determine the slowest heating zone (SHZ) during the thermal processing. The temperature profile was obtained and recorded experimentally at a point where the coldest thermal point was expected. CFD models were validated against experimental data. The results of the study showed that the SHZ was located at the geometric center of the containers (x = 5.00, y = 1.42, z = 6.75 cm), and the temperature reached 119.5 °C. Root mean square error (RMSE) was calculated and showed a good fit between both methods (RMSE = 1.03). The container geometrical center F0 was estimated to be 13.19 min. For optimization of the process, according to the stew ingredients, especially meat, F0 was about 8 min. Thus, the required holding time was decreased by 5.19 min, and the retort setting was readjusted.


2021 ◽  
Vol 2059 (1) ◽  
pp. 012003
Author(s):  
A Burmistrov ◽  
A Raykov ◽  
S Salikeev ◽  
E Kapustin

Abstract Numerical mathematical models of non-contact oil free scroll, Roots and screw vacuum pumps are developed. Modelling was carried out with the help of software CFD ANSYS-CFX and program TwinMesh for dynamic meshing. Pumping characteristics of non-contact pumps in viscous flow with the help of SST-turbulence model were calculated for varying rotors profiles, clearances, and rotating speeds. Comparison with experimental data verified adequacy of developed CFD models.


2021 ◽  
Author(s):  
Sanaz Dianat

The research paper investigates the impact of a window’s exterior air film on the assembly temperature. The exterior air film constitutes a vital portion of a window’s insulating values. The air film increases the temperature of the window exterior pane to a temperature above ambient temperature. The air film also rises the interior glass temperature and reduces the heat transfer from the interior surface. According to computational fluid dynamics (CFD), the air film is removed in windy conditions, decreasing the window temperature on the outside as well as on the inside. The idea behind the project is to carry out an experimental procedure on three different windows to validate the CFD results, which indicates the effect of various wind speeds. Keyword: Exterior air film, computational fluid dynamics, window assembly, wind speed


2021 ◽  
Author(s):  
Sanaz Dianat

The research paper investigates the impact of a window’s exterior air film on the assembly temperature. The exterior air film constitutes a vital portion of a window’s insulating values. The air film increases the temperature of the window exterior pane to a temperature above ambient temperature. The air film also rises the interior glass temperature and reduces the heat transfer from the interior surface. According to computational fluid dynamics (CFD), the air film is removed in windy conditions, decreasing the window temperature on the outside as well as on the inside. The idea behind the project is to carry out an experimental procedure on three different windows to validate the CFD results, which indicates the effect of various wind speeds. Keyword: Exterior air film, computational fluid dynamics, window assembly, wind speed


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