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.

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.

Study of Condensation Flow Patterns and Heat Transfer Characteristic on a Horizontal Tube Bundle

2016 ◽  
Author(s):  
Hongfang Gu ◽  
Qi Chen ◽  
Zhe Zhang ◽  
Haiyang Guo
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Mass Transfer ◽  
Flow Regime ◽  
Heat And Mass Transfer ◽  
Tube Bundle ◽  
Flow Patterns ◽  
Heat Transfer Characteristics ◽  
Controlled Flow ◽  
Condensation Flow

The numerous studies on condensation flow patterns and heat transfer were focused on the horizontal inside single tube. A number of heat and mass transfer correlations are used for design of shellside condensers based on tubeside condensation flow regimes. Due to a complex geometry and measurement difficulty in a tube bundle, there are few publications reported on shellside condensation flow regime and heat transfer characteristics. To investigate the condensation flow patterns and heat and mass transfer mechanism at the different flow regimes, a horizontal shellside condenser was tested from a multipurpose condensation rig recently. The horizontal test bundle is made of 36 tubes with the staggered tube layout. The tube OD is 19 mm and the tube length is 1.0 m using stainless steel. Four visualization windows were placed on the front and back sides on the shell for photographing condensation flow patterns. Steam and steam/air mixture were used as the test fluids. The condensation flow patterns, condensate film thickness and droplets distribution were recorded using a high-speed digital camera at a wide range of condensation process conditions. The experimental data show that the condensation flow regime changes from the shear-controlled flow to gravity-controlled flow depending on the vapor and condensate loads, bundle location and the concentration of the non-condensable gas. These experimental data provide a fundamental approach for developing the heat and mass transfer correlateons at different shellside condensation patterns. This paper presents the experimental result on shellside condensation patterns associated with heat transfer characteristics.

scholarly journals EFFECT OF PERMEABILITY OF PEBLE BED ON HEAT TRANSFER IN THE CORE OF NUCLEAR REACTOR WITH HELIUM COOLANT

2017 ◽  
Vol 39 (4) ◽  
pp. 55-60
Author(s):  
A. A. Avramenko ◽  
N. P. Dmitrenko ◽  
М. M. Kovetskaya ◽  
Yu. Yu. Kovetskaya
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Temperature Distribution ◽  
Heat And Mass Transfer ◽  
Nuclear Reactor ◽  
Reactor Core ◽  
Geometric Parameters ◽  
The Core ◽  
Fuel Elements ◽  
Helium Coolant

Heat and mass transfer in a model of the core of a nuclear reactor with spherical fuel elements and a helium coolant was studied. The effect of permeability of the pebble bed zone and geometric parameters on the temperature distribution of the coolant in the reactor core is analyzed.  

Paper 8: Heat Transfer from a Wire in the Critical Region

1967 ◽  
Vol 182 (9) ◽  
pp. 52-57 ◽  
Author(s):  
U. Grigull ◽  
E. Abadzic
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Natural Convection ◽  
Critical Point ◽  
Critical Region ◽  
High Speed ◽  
Nucleate Boiling ◽  
Flow Patterns ◽  
Film Boiling ◽  
High Speed Camera

This work deals with experimental results on boiling from a horizontal platinum wire, 0·1 mm in diameter, submerged in saturated liquids as carbon dioxide (CO2) and Freon 13 (CF3Cl) in the critical region. Three discrete regimes without steady transition could be observed: natural convection, nucleate boiling, and film boiling. Near the critical point particular flow patterns appeared in the rising vapour in film boiling: regular bubbles, vapour columns, and vapour hazes with garland-like boundaries. These flow patterns could be simulated in model experiments with liquids and were also photographed with a high-speed camera.

scholarly journals Effect of Acceleration on the Heat Transfer Coefficient on a Film Cooled Surface

1990 ◽  
Author(s):  
H. D. Ammari ◽  
N. Hay ◽  
D. Lampard
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Mass Transfer ◽  
Experimental Investigation ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Density Ratio ◽  
Base Line ◽  
Density Ratios ◽  
The Heat Transfer Coefficient

Results are presented of an experimental investigation into the influence of mainstream acceleration on the heat transfer coefficient downstream of injection through a row of 35° holes in a flat plate. A mass transfer analogue technique was used, with two uniform acceleration parameters, K (=ν(du∞/dx)/u∞2), of 1.9 × 10−6 and 5.0 × 10−6 in addition to the zero acceleration base-line case. Two injectants, air and carbon dioxide, were employed to give coolant to mainstream density ratios of 1.0 and 1.52 respectively. The blowing rate varied from 0.5 to 2.0. The heat transfer coefficient beneath the film reduced progressively as the acceleration increased, with maximum reductions from the zero acceleration datum case of about 27%. In the presence of acceleration, the heat transfer coefficient at a given blowing rate was dependent on the density ratio, an increase in the density ratio leading to a decrease in the heat transfer coefficient. An empirical correlation of the data over most of the range of densities and blowing rates of the experiments has been developed.

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.

Operation of a Porous Membrane Photobioreactor

2016 ◽  
Author(s):  
Gary A. Anderson ◽  
Sarmila Katuwal ◽  
Anil Kommareddy ◽  
Stephen Gent
Keyword(s):  
Carbon Dioxide ◽  
Flow Pattern ◽  
Growth Medium ◽  
Light Guide ◽  
Porous Membrane ◽  
Lag Phase ◽  
Growth Media ◽  
Wall Area ◽  
Reactor Volume ◽  
Light Guides

A unique photobioreactor (PBR) constructed with acrylic sheet was used to grow S. Leopoliensis in 3.36 litters of Scully’s growth media. The PBR width was 51mm with a 273mm length and a growth media depth of 271mm. One of the PBR unique features was that it used a plenum and a porous membrane to inject air enriched with carbon dioxide into the growth medium. The HDPE (high-density polyethylene sintered beads) porous membrane served as the barrier between the reactor volume and the mixing plenum of the PBR. The air bubbled up through the porous membrane into the reactor volume with the growth medium mixing the contents of the reactor volume and transfer oxygen and carbon dioxide between the growth media and the bubbles. The second unique feature of the PBR is that it incorporated light guides in the design. The light guides were acrylic rods 9.5mm in diameter and a length projecting into the reactor volume of 38.1mm. The guides did not touch the opposite PBR wall. The light guides were abraded with sand paper on the outer to enhance light transfer from the guide to the growth medium. There were eight rows of light guides on each of the two PBR walls that were 273mm in length. Each row consisted of eight light guides space 34.1mm apart and 17.1mm from the side (short) walls of the PBR. Light was provided by two LED panels with 384 LED lights on each panel. The light from the panels had a wavelength of 650nm. The Light guides protruded through the PBR wall and light from the LED panels entered the light guide ends or transferred through the wall directly into the PBR reactor volume. The light guide ends occupied approximately 16% of the PBR wall area lit by the LED panels. The PBR produced 7.1g per litter of algal biomass in a 14 day growth cycle which encompassed a 3 day lag phase. The light guides disrupted the bubble flow pattern not allowing an obvious riser and/or downcomer to develop in the reactor volume. The disrupted flow pattern enhanced mixing and gas transfer. The enhanced mixing rotated the algal cells from more to less areas of the reactor volume more often aiding photosynthesis in a manner similar to flashing lights.

Effect of Acceleration on the Heat Transfer Coefficient on a Film-Cooled Surface

1991 ◽  
Vol 113 (3) ◽  
pp. 464-471 ◽  
Author(s):  
H. D. Ammari ◽  
N. Hay ◽  
D. Lampard
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Mass Transfer ◽  
Experimental Investigation ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Density Ratio ◽  
Baseline Case ◽  
Density Ratios ◽  
The Heat Transfer Coefficient

Results are presented of an experimental investigation into the influence of mainstream acceleration on the heat transfer coefficient downstream of injection through a row of 35 deg holes in a flat plate. A mass transfer analogue technique was used, with two uniform acceleration parameters, K ( = v(du∞/dx)/u2∞, of 1.9 × 10−6 and 5.0×10−6 in addition to the zero acceleration baseline case. Two injectants, air and carbon dioxide, were employed to give coolant-to-mainstream density ratios of 1.0 and 1.52, respectively. The blowing rate varied from 0.5 to 2.0. The heat transfer coefficient beneath the film decreased progressively as the acceleration increased, with maximum reductions from the zero acceleration datum case of about 27 percent. In the presence of acceleration, the heat transfer coefficient at a given blowing rate was dependent on the density ratio, an increase in the density ratio leading to a decrease in the heat transfer coefficient. An empirical correlation of the data over most of the range of densities and blowing rates of the experiments has been developed.

Sign in / Sign up

Export Citation Format

Share Document