scholarly journals Multi-Tubular Reactor for Hydrogen Production: CFD Thermal Design and Experimental Testing

Processes ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 31 ◽  
Author(s):  
Elvira Tapia ◽  
Aurelio González-Pardo ◽  
Alfredo Iranzo ◽  
Manuel Romero ◽  
José González-Aguilar ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Experimental Testing ◽  
Tubular Reactor ◽  
Experimental Tests ◽  
Thermal Design ◽  
Thermochemical Cycle ◽  
Cfd Model ◽  
Cfd Modelling ◽  
Solar Reactor ◽  
Computational Fluid Dynamics Cfd

This study presents the Computational Fluid Dynamics (CFD) thermal design and experimental tests results for a multi-tubular solar reactor for hydrogen production based on the ferrite thermochemical cycle in a pilot plant in the Plataforma Solar de Almería (PSA). The methodology followed for the solar reactor design is described, as well as the experimental tests carried out during the testing campaign and characterization of the reactor. The CFD model developed for the thermal design of the solar reactor has been validated against the experimental measurements, with a temperature error ranging from 1% to around 10% depending on the location within the reactor. The thermal balance in the reactor (cavity and tubes) has been also solved by the CFD model, showing a 7.9% thermal efficiency of the reactor. CFD results also show the percentage of reacting media inside the tubes which achieve the required temperature for the endothermic reaction process, with 90% of the ferrite pellets inside the tubes above the required temperature of 900 °C. The multi-tubular solar reactor designed with aid of CFD modelling and simulations has been built and operated successfully.

scholarly journals Experimental testing of multi-tubular reactor for hydrogen production and comparison with a thermal CFD model

2018 ◽  
Author(s):  
Elvira Tapia ◽  
Aurelio González-Pardo ◽  
Alfredo Iranzo ◽  
Alfonso Vidal ◽  
Felipe Rosa
Keyword(s):  
Hydrogen Production ◽  
Experimental Testing ◽  
Tubular Reactor ◽  
Cfd Model

Application of CFD modelling at a full-scale ozonation plant for the removal of micropollutants from secondary effluent

2013 ◽  
Vol 68 (6) ◽  
pp. 1336-1344 ◽  
Author(s):  
M. Launer ◽  
S. Lyko ◽  
H. Fahlenkamp ◽  
P. Jagemann ◽  
P. Ehrhard
Keyword(s):  
Full Scale ◽  
Secondary Effluent ◽  
Cfd Model ◽  
Process Data ◽  
Cfd Modelling ◽  
Reaction Rate Constants ◽  
Batch Tests ◽  
Reactor Geometry ◽  
Computational Fluid Dynamics Cfd ◽  
The Given

Since November 2009, Germany's first full-scale ozonation plant for tertiary treatment of secondary effluent is in continuous operation. A kinetic model was developed and combined with the commercial computational fluid dynamics (CFD) software ANSYS® CFX® to simulate the removal of micropollutants from secondary effluents. Input data like reaction rate constants and initial concentrations of bulk components of the effluent organic matter (EfOM) were derived from experimental batch tests. Additionally, well-known correlations for the mass transfer were implemented into the simulation model. The CFD model was calibrated and validated by full-scale process data and by analytical measurements for micropollutants. The results show a good consistency of simulated values and measured data. Therewith, the validated CFD model described in this study proved to be suited for the application of secondary effluent ozonation. By implementing site-specific ozone exposition and the given reactor geometry the described CFD model can be easily adopted for similar applications.

CFD Modelling of Liquid Poison Injection in ACR-1000 Shutdown System

2008 ◽  
Author(s):  
F. Song ◽  
R. Noghrehkar ◽  
K. F. Hau
Keyword(s):  
Reactor Core ◽  
Basic Design ◽  
Nozzle Design ◽  
Cfd Model ◽  
Cfd Modelling ◽  
Type Reactor ◽  
Ansys Cfx ◽  
Liquid Injection ◽  
Computational Fluid Dynamics Cfd ◽  
Reactor Shutdown

The Liquid Injection Shutdown System (LISS) is a safety system in the CANDU™-type reactor to provide rapid reactor shutdown by automatically injecting a neutron absorbing liquid (“poison”), via injection nozzles, into the moderator in the calandria. The poison distribution in the moderator plays a significant role in the shutdown performance. The Advanced CANDU Reactor (ACR-1000™) is a Generation III+ type reactor as an evolutionary extension of the proven CANDU-6 reactor. The basic design concept of the CANDU-6 LISS is adopted for the ACR-1000. The injection nozzle design has been modified to suit the ACR-1000 reactor core configuration. In this study, a Computational Fluid Dynamics (CFD) model was developed using the ANSYS-CFX software to examine the poison injection characteristics in the ACR-1000 design. The effects of calandria tubes on the poison jet growth and poison distribution in the reactor core were discussed.

Hydrodynamic evaluation of a full-scale facultative pond by computational fluid dynamics (CFD) and field measurements

2014 ◽  
Vol 70 (3) ◽  
pp. 569-575 ◽  
Author(s):  
Ricardo Gomes Passos ◽  
Marcos von Sperling ◽  
Thiago Bressani Ribeiro
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Short Circuit ◽  
Field Measurements ◽  
Tracer Test ◽  
Full Scale ◽  
Cfd Model ◽  
Cfd Modelling ◽  
Hydraulic Behaviour ◽  
Computational Fluid Dynamics Cfd

Knowledge of the hydraulic behaviour is very important in the characterization of a stabilization pond, since pond hydrodynamics plays a fundamental role in treatment efficiency. An advanced hydrodynamics characterization may be achieved by carrying out measurements with tracers, dyes and drogues or using mathematical simulation employing computational fluid dynamics (CFD). The current study involved experimental determinations and mathematical simulations of a full-scale facultative pond in Brazil. A 3D CFD model showed major flow lines, degree of dispersion, dead zones and short circuit regions in the pond. Drogue tracking, wind measurements and dye dispersion were also used in order to obtain information about the actual flow in the pond and as a means of assessing the performance of the CFD model. The drogue, designed and built as part of this research, and which included a geographical positioning system (GPS), presented very satisfactory results. The CFD modelling has proven to be very useful in the evaluation of the hydrodynamic conditions of the facultative pond. A virtual tracer test allowed an estimation of the real mean hydraulic retention time and mixing conditions in the pond. The computational model in CFD corresponded well to what was verified in the field.

CFD Modelling of a Choke Valve Under Critical Working Conditions

2014 ◽  
Author(s):  
Stefano Malavasi ◽  
Gianandrea Vittorio Messa
Keyword(s):  
Experimental Tests ◽  
Flow Coefficient ◽  
Unexpected Result ◽  
Cfd Model ◽  
Cfd Modelling ◽  
Cfd Simulations ◽  
Gas Industry ◽  
Valve Opening ◽  
Coefficient Versus ◽  
Convective Fluxes

Choke valves are widely used in the oil&gas industry to control the fluid flowing in the system. Some of these valves rely on a “cage and sleeve” functioning, in which an outer, sliding sleeve controls the flow rate by overlapping the holes of an inner, fixed cage. The regulation characteristic of choke valves is typically quantified by the opening curve, which is the plot of the flow coefficient versus the valve opening. Experimental tests performed on a “cage and sleeve” choke valve revealed that the orientation of the holes of the cage affects significantly the flow coefficient. This work focuses on the worst situation encountered, in which an anomalous decreasing trend in the opening curve for large valve openings is accompanied by strong vibrations of the device. CFD simulations were run to provide a physical interpretation of this unexpected result. Due to the complexity of the flow field structure at the origin of this behavior particular attention was paid in properly defining the CFD model; the turbulence model and the differencing scheme for the convective fluxes were found to be the most significant parameters. The CFD runs allowed attributing the anomalous trend of the opening curve to the peculiar interactions of the jets within the cage. At last, a modification of the trim design is suggested for avoiding the malfunctioning of the valve and the abnormal vibrations.

CFD Modelling of Moisture Content, Air Velocity and Thermal Patterns in the Tombs of Horemeheb in Valley of Kings

2011 ◽  
Author(s):  
Essam E. Khalil
Keyword(s):  
Design System ◽  
Wall Paintings ◽  
Careful Selection ◽  
Cfd Model ◽  
Air Velocity ◽  
Cfd Modelling ◽  
Recirculation Zones ◽  
Computational Fluid Dynamics Cfd ◽  
Thermal Patterns ◽  
Selection Of

Airflow characteristics in ventilated and air-conditioned spaces play an important role to attain comfort and hygiene conditions. This paper utilizes a 3D Computational Fluid Dynamics (CFD) model to assess the airflow and relative humidity characteristics in ventilated and air-conditioned archaeological tomb of Horemheb in the Valley of the Kings in Luxor, Egypt. It is found that the best airside design system can be attained, if the airflow is directed to pass all the enclosure areas before the extraction with careful selection of near wall velocities to avoid any wear or aberration of the tomb-wall paintings. Still all factors and evaluation indices have the shortage to describe the influence of the recirculation zones on the occupancy zone of the visitors and also on the fresh supplied air. The mode of evaluation should assess the airflow characteristics in any tomb passage according to its position in the enclosure and the thermal pattern and air quality.

Experimental Analysis of a Micro Gas Turbine Combustor Optimized For Flexible Operation With Various Gaseous Fuel Compositions

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Hannah E. Bower ◽  
Andreas Schwärzle ◽  
Felix Grimm ◽  
Timo Zornek ◽  
Peter Kutne
Keyword(s):  
Gas Turbines ◽  
Experimental Testing ◽  
Experimental Tests ◽  
Atmospheric Pollutant ◽  
Gas Emissions ◽  
Micro Gas Turbine ◽  
Fuel Flexibility ◽  
Computational Fluid Dynamics Cfd ◽  
Lift Off ◽  
Flexible Operation

Abstract With the push to curb dangerous atmospheric pollutant production, energy generation technologies that reduce green-house gas emissions, while still providing adequate electrical supply, are of high importance. With major energy infrastructure already in place, developing enhanced pollutant-reducing combustor systems for micro gas turbines (MGTs), that can utilize low calorific fuels from renewable resources, is a major goal. The current work focuses on the experimental testing of an optimized two-stage combustor designed to operate with various fuel types, including natural gas and syngas produced via biomass gasification. Atmospheric experimental tests were performed and the results indicate larger flame lift-off heights and slightly higher CO gas emissions levels, while displaying lower NOx gas emissions levels for all thermal loads and air-to-fuel equivalence ratios tested, compared to that of the previous combustor designs. Additionally, steady-state computational fluid dynamics (CFD) simulations were conducted and the results are in general good agreement with the experimental data. Overall, the results indicate high fuel flexibility of the combustor, as well as the ability to comply with the NOx emissions limits for a larger range of operating points, compared to that of the previously tested combustors.

scholarly journals Using CFD Modelling to Relate Pig Lying Locations to Environmental Variability in Finishing Pens

2020 ◽  
Vol 12 (5) ◽  
pp. 1928 ◽  
Author(s):  
Paul Jackson ◽  
Abozar Nasirahmadi ◽  
Jonathan H. Guy ◽  
Steve Bull ◽  
Peter J. Avery ◽  
...  
Keyword(s):  
Environmental Variability ◽  
Weather Conditions ◽  
Environmental Drivers ◽  
Cfd Model ◽  
Air Velocity ◽  
Cfd Modelling ◽  
Video Cameras ◽  
Finishing Pig ◽  
Computational Fluid Dynamics Cfd ◽  
Sequential Regression

The purpose of this research was to determine which environmental factors within the pen space differ between the locations where pigs choose to lie and areas they avoid. Data on external weather conditions and the construction parameters for an existing commercial finishing pig building were input into a Dynamic Thermal (DT) model generating heat flow and surface temperature patterns in the structure and these were then input into a Computational Fluid Dynamics (CFD) model to generate data on the theoretical spatial patterns of temperature and air velocity within one room of this building on a specified day. The exact location of each pig in six selected pens within this room was taken from images from ceiling-mounted video cameras at four representative time points across the day. Using extracted air velocity and temperature data at the height of 0.64 m above the floor and a grid of approximately 600 mm to create a series of ‘cells’, the effective draught temperature (TED) was calculated from the models for each cell. Using a sequential regression model, the extent to which the actual lying locations of the pigs could be reliably predicted from the environmental conditions generated by model outputs and other pen factors was explored. The results showed that air velocity, TED and proximity to a solid pen partition (all significant at P < 0.05) had significant predictive value and collectively explained 15.55% of the total explained deviation of 17.13%. When the presence of an adjacent pig was considered, results showed that lying next to an adjacent pig, TED, air velocity and temperature accounted for 53.9%, 1.3%, 1.5% and 0.5% of the deviation in lying patterns, respectively (all P < 0.001). Thus, CFD model outputs could potentially provide the industry with a better understanding of which environmental drivers affect pigs’ lying location choice, even before a building is built and stocked.

CFD Modelling With Buoyancy Effects for a Heat and Moisture Transfer Ceiling Panel

2011 ◽  
Author(s):  
Melanie Fauchoux ◽  
Carey Simonson ◽  
David Torvi ◽  
Prabal Talukdar
Keyword(s):  
Flow Field ◽  
Moisture Transfer ◽  
Cfd Model ◽  
Heat And Moisture Transfer ◽  
Cfd Modelling ◽  
Flow Field Characteristics ◽  
Computational Fluid Dynamics Cfd ◽  
The University ◽  
Heat And Moisture ◽  
Insight Into

A heat and moisture transfer panel (HAMP) capable of simultaneously transferring heat and moisture to/from a space to improve indoor air conditions is being developed at the University of Saskatchewan. Experiments have been performed for different air conditions to simulate heating, cooling, humidification and dehumidification of the air by the HAMP. A latent effectiveness value is calculated for each test to show the performance of the HAMP. The HAMP has the highest effectiveness (∼45%) when used to cool the airflow. When used to heat the airflow, the effectiveness is much lower (∼25%). This difference can be attributed to the presence of large buoyancy forces during cooling in comparison to heating. To observe the flow field characteristics under the varying test conditions, a computational fluid dynamics (CFD) model is developed. The CFD model is able to provide a better insight into the features of the flow field. The presented streamlines and isotherms exhibit the effect of buoyancy for various conditions and help in understanding the experimentally determined effectivenesses.

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