Investigation of Hydrodynamics and Heat Transfer Effects Due to Light Guides in a Column Photobioreactor

2014 ◽  
Vol 11 (4) ◽  
Author(s):  
Caitlin R. Gerdes ◽  
Taylor N. Suess ◽  
Gary A. Anderson ◽  
Stephen P. Gent
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Bubble Flow ◽  
Flow Rates ◽  
Photosynthetic Organisms ◽  
Temperature Distributions ◽  
Computational Fluid Dynamics Cfd ◽  
Heat Transfer Effects ◽  
Growing Conditions ◽  
Light Guides

The objective of this research is to predict how the placement of structural light guides within a column photobioreactor (PBR) affects the fluid mechanics and heat transfer of the system. The photobioreactor studied is modeled and analyzed using computational fluid dynamics (CFD). A bubble sparger provides carbon dioxide and mixing. Five different arrays and eight carbon dioxide volumetric flow rates are tested. Based on this setup, the bubble flow patterns, velocities, and temperature distributions are analyzed and the recommended placement of light guides is determined for predicting the growing conditions suitable for microalgae and other photosynthetic organisms.

Investigation of Hydrodynamics and Heat Transfer Effects due to Light Guides in a Column Photobioreactor

2013 ◽  
Author(s):  
Caitlin Gerdes ◽  
Taylor N. Suess ◽  
Gary A. Anderson ◽  
Stephen P. Gent
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Mass Transfer ◽  
Temperature Distribution ◽  
Light Guide ◽  
Flow Patterns ◽  
Light Penetration ◽  
Algae Growth ◽  
Computational Fluid Dynamics Cfd ◽  
Light Guides

Proper light penetration is an essential design consideration for effective algae growth in column photobioreactors. This research focuses on the placement of light guides within a photobioreactor (PBR), and the effect they have on heat transfer, mass transfer, bubble and fluid flow patterns, and mixing. Studies have been done on a rectangular column photobioreactor (34.29 cm long × 15.25 cm wide × 34.29 cm tall) with two light panels along the front and back of the PBR. A bubble sparger is placed along the center of the bottom length of the PBR with both height and width of 1.27 cm and a length of 33.02 cm. Different configurations and numbers of light guides (1.27 cm diameter) running horizontally from the front to the back of the PBR are modeled using the Computational Fluid Dynamics (CFD) software Star-CCM+. It is hypothesized that the addition of light guides will change the flow pattern but not adversely affect the heat or mass transfer of the carbon dioxide bubbles within the PBR. Potential concerns of light guide placement include inhibiting the flow of the carbon dioxide bubbles or creating regions of high temperature, which could potentially kill the algae. Benefits of light guides include increased light penetration and photosynthesis within the PBR. Five different light guide setups are tested with the carbon dioxide bubbles and water modeled as a turbulent multiphase gas-liquid mixture. The near wall standard k-epsilon two layer turbulence model was used, as it takes into account the viscosity influences between the liquid and gaseous phases. Eight different bubble volumetric flow rates are simulated. The bubble flow patterns, temperature distribution, Nusselt number, Reynolds number, and velocity are all analyzed. The results indicate square arrays of light guides give the most desirable velocity distribution, with less area of zero velocity compared to the staggered light guide setup. Temperature distribution is generally even for all configurations of light guides.

A Computational Fluid Dynamic Study of a Momentum and Energy Method on Rough Surfaces

2020 ◽  
Author(s):  
Jose Urcia ◽  
Michael Kinzel
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamic ◽  
Roughness Element ◽  
Flow Rates ◽  
Pressure Drops ◽  
The Core ◽  
Roughness Elements ◽  
Momentum Correlation ◽  
The Matrix ◽  
Computational Fluid Dynamics Cfd

Abstract The Discrete Element Roughness Method (DERM) has been used to improve convective heat transfer predictions on surface roughness. This work aims to validate the core momentum-correlation of DERM through evaluating Computational fluid dynamics (CFD)-based solution of the flow around individual roughness elements with the goal of improving the correlations. More specifically, the matrix of scenarios evaluated using includes three different roughness elements at three different pressure drops (or flow rates). Results from these studies are to be used to validate and improve correlations used to approximate roughness in DERM. For further comparison, a fourth roughness element analyzed in previous work will also be compared. For each element, a steady and unsteady case are conducted and analyzed. The momentum loss results obtained from the CFD are then compared to the DERM-based predictions from the same roughness elements in search of any discrepancies. It is observed the momentum-correlation deviates from the CFD prediction with increasing element height.

A Methodology for Blast Furnace Hearth Inner Profile Analysis

2007 ◽  
Vol 129 (12) ◽  
pp. 1729-1731 ◽  
Author(s):  
Yu Zhang ◽  
Rohit Deshpande ◽  
D. Huang ◽  
Pinakin Chaubal ◽  
Chenn Q. Zhou
Keyword(s):  
Heat Transfer ◽  
Blast Furnace ◽  
Profile Analysis ◽  
Furnace Hearth ◽  
Temperature Distributions ◽  
Blast Furnace Hearth ◽  
Computational Fluid Dynamics Cfd ◽  
The Difference ◽  
New Algorithms ◽  
Face Temperature

The wear of a blast furnace hearth and the hearth inner profile are highly dependent on the liquid iron flow pattern, refractory temperatures, and temperature distributions at the hot face. In this paper, the detailed methodology is presented along with the examples of hearth inner profile predictions. A new methodology along with new algorithms is proposed to calculate the hearth erosion and its inner profile. The methodology is to estimate the hearth primary inner profile based on 1D heat transfer and to compute the hot-face temperature using the 3D CFD hearth model according to the 1D preestimated and reestimated profiles. After the hot-face temperatures are converged, the hot-face positions are refined by a new algorithm, which is based on the difference between the calculated and measured results, for the 3D computational fluid dynamics (CFD) hearth model further computations, until the calculated temperatures well agree with those measured by the thermocouples.

Simulation Study on Heat Insulating Material Used in Refrigerated Cargo Hold Shipboard of Fishing Vessel

2011 ◽  
Vol 311-313 ◽  
pp. 1953-1956
Author(s):  
Jing Fu Jia ◽  
Wei He
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Heat Transfer Process ◽  
Transfer Model ◽  
Fishing Vessel ◽  
Transfer Property ◽  
Insulating Material ◽  
Temperature Distributions ◽  
Heat Transfer Property ◽  
Computational Fluid Dynamics Cfd

To choose the suitable heat insulating material for refrigerated cargo hold shipboard of fishing vessel, a steady state three-dimensional mathematical model of heat transfer is developed in this paper. The heat-transfer model is simplified reasonably in order to facilitate analyzing and solving. After defining the boundary conditions of the model according to the heat-transfer process of the shipboard, numerical simulations with different heat insulating material are performed using computational fluid dynamics (CFD) software PHOENICS. The obtained temperature distributions of the model in each case are analyzed. The suitable one is pointed out according to the degree of influence of the heat insulating material on heat-transfer property of the shipboard.

Sensing and Modeling Techniques for Micro and Nano Scale Transport

2006 ◽  
Author(s):  
Sung Jin Kim ◽  
Dong-Kwon Kim
Keyword(s):  
Heat Transfer ◽  
Averaging Method ◽  
Thermal Design ◽  
Flow Rates ◽  
Design And Optimization ◽  
Flow And Heat Transfer ◽  
Temperature Distributions ◽  
Modeling Techniques ◽  
Modeling Transport ◽  
Mass Flow Rates

In the present study, three types of micro-sensors developed for experimental investigation of fluid flow and heat transfer in microstructures are introduced. The micro-sensors can be used to measure temperature distributions at the surface of a microstructure and mass flow rates passing through it. It is followed by a description of a method for modeling transport phenomena in microstructures is introduced. The modeling technique, based on the averaging method, is illustrated in thermal design and optimization of a microstructure.

Study of the Freezing Chuck for Non-Traditional Clamping Applications

2010 ◽  
Author(s):  
Rong-Yuan Jou
Keyword(s):  
Heat Transfer ◽  
Numerical Simulations ◽  
Transient State ◽  
Experimental Measurements ◽  
Thermoelectric Coolers ◽  
Flow Rates ◽  
Temperature Distributions ◽  
Surface Temperatures ◽  
Convective Fluid ◽  
Heat Transfers

A freezing chuck with thermoelectric coolers and coolant channels is investigated. Measurement for freezing/thawing processes and analysis of heat transfer enhancements are conducted. Three channel configurations are designed and investigated by numerical simulations and experimental measurements, respectively, to compare the temperature distributions and heat transfer enhancements. Regarding to experiments, inlet temperatures and flow rates of coolants are altered, and transient and steady surface temperatures on the top-plate are measured for these three channel designs. In numerical analysis, convective fluid flows and heat transfers are solved to find temperature, velocity, and pressure fields inside the channel and surface temperatures of top-plate of the freezing chuck by a software package. Comparisons between experimental measurements and numerical simulations are made. Effects of flow rates, inlet coolant temperatures, and channel designs, upon the steady and transient state of temperature distributions and heat transfer enhancements are discussed and conclusions are addressed.

scholarly journals Modeling an Airlift Reactor for the Growing of Microalgae

2018 ◽  
Vol 12 (1) ◽  
pp. 80-94
Author(s):  
Gustavo A. Lara ◽  
Luis Moreno ◽  
Yendery Ramírez ◽  
Luis A. Cisternas
Keyword(s):  
Fluid Dynamics ◽  
Carbon Dioxide ◽  
Flow Dynamics ◽  
Airlift Reactor ◽  
Air Injection ◽  
Reactor Operation ◽  
Flow Rates ◽  
Injection Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Liquid Movement

Objective: The flow dynamics of an airlift reactor for the growing of microalgae is modeled using Computational Fluid Dynamics (CFD). The model is applied to the operation and optimization of the reactor, giving a valuable picture of the liquid movement and carbon dioxide trajectory at different air injection flow rates. Methods: A novel aspect of the model is that air and carbon dioxide are injected at separated locations. Air is injected at the bottom of the reactor and CO2 injection takes place in the downcomer region of the reactor to obtain longer CO2 paths, improving its transference. Results: The results show modeling is a useful tool in the control of the reactor operation; for example, in avoiding the sedimentation of microalgae or for detecting the existence of zones with extremely low CO2 concentrations.

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
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Porous Membrane ◽  
Flow Patterns ◽  
Transfer Effects ◽  
Eulerian Approach ◽  
Cfd Models ◽  
Computational Fluid Dynamics Cfd ◽  
Heat Transfer Effects

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.

Use of Regular Rod Arrays to Model Heat Transfer From BWR Fuel Assemblies Inside Transport Casks

2007 ◽  
Author(s):  
Pablo E. Araya ◽  
Miles Greiner
Keyword(s):  
Heat Transfer ◽  
Spent Nuclear Fuel ◽  
Two Dimensional ◽  
Fuel Cladding ◽  
Cfd Simulations ◽  
Fuel Assemblies ◽  
Computational Fluid Dynamics Cfd ◽  
Heat Transfer Effects ◽  
Computational Resources ◽  
Volume Mesh

The current work is a scoping study to determine which heat transfer effects are significant in the fuel/backfill gas region of spent nuclear fuel transport casks. A two-dimensional finite volume mesh that accurately models the geometry of a 7×7 Boiling Water Reactor (BWR) assembly with its channel in a square isothermal enclosure is constructed. The peak cladding temperature is determined using computational fluid dynamics (CFD) simulations for a range of enclosure temperatures, fuel heat generation rates, cladding surface emissivities, and for both nitrogen and helium backfill gases. This work quantifies both the effect of buoyancy induced gas motion in the fuel/backfill gas region and the conditions when it does not significantly affect heat transfer. Future cask design simulations that neglect gas motion will require less computational resources than ones that do not. This work also quantifies the sensitivity of the maximum cladding temperature to fuel cladding emissivity. This helps quantify the uncertainty of temperature predictions if the emissivity is not known. The current CFD technique must be experimentally benchmarked before it may be used with confidence to predict peak cladding temperatures in transport casks. This work indicates that the thermal resistance between a BWR assembly’s channel and the basket walls may be modeled analytically. This will reduce the effort required for benchmark experiments because they will not need to include the channel.

Hydrodynamic and Heat Transfer Effects of Varying Sparger Spacing Within a Column Photobioreactor Using Computational Fluid Dynamics

2015 ◽  
Vol 12 (1) ◽  
Author(s):  
Ghazi S. Bari ◽  
Taylor N. Suess ◽  
Gary A. Anderson ◽  
Stephen P. Gent
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
The Other ◽  
Transfer Effects ◽  
Computational Fluid Dynamics Cfd ◽  
Heat Transfer Effects

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.

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