Immersive Visualization of Dynamic CFD Model Results

2004 ◽  
Author(s):  
Joseph R. Comparato ◽  
Karen L. Ringel ◽  
Daniel L. Heath
Keyword(s):  
Data Management ◽  
Fluid Dynamic ◽  
Fast Response ◽  
Cfd Modeling ◽  
Improve Design ◽  
Commodity Hardware ◽  
Mathematical Simulations ◽  
Commodity Computing ◽  
Visualization Techniques ◽  
Immersive Visualization

With immersive visualization the engineer has the means for vividly understanding problem causes and discovering opportunities to improve design. Software can generate an interactive world in which collaborators experience the results of complex mathematical simulations such as computational fluid dynamic (CFD) modeling. Such software, while providing unique benefits over traditional visualization techniques, presents special development challenges. The visualization of large quantities of data interactively requires both significant computational power and shrewd data management. On the computational front, commodity hardware is outperforming large workstations in graphical quality and frame rates. Also, 64-bit commodity computing shows promise in enabling interactive visualization of large datasets. Initial interactive transient visualization methods and examples are presented, as well as development trends in commodity hardware and clustering. Interactive, immersive visualization relies on relevant data being stored in active memory for fast response to user requests. For large or transient datasets, data management becomes a key issue. Techniques for dynamic data loading and data reduction are presented as means to increase visualization performance.

CFD Modeling of Thermal Management Systems for a Silicon Semiconductor Switch

2020 ◽  
Author(s):  
Jordan N. Berg ◽  
Sarvenaz Sobhansarbandi
Keyword(s):  
Thermal Management ◽  
Fluid Dynamic ◽  
Jet Impingement ◽  
Liquid System ◽  
Pulse Power ◽  
Cfd Modeling ◽  
Inlet Temperature ◽  
Ansys Fluent ◽  
Term Operation ◽  
Semiconductor Switches

Abstract Silicon semiconductor switches are suitable for pulse power applications. When utilized in these applications, the switch receives a significant amount of power (i.e., heat) that is to be dissipated, which can result in the degradation of the switch. In order to maintain the functionality of the switch, a thermal management system (TMS) needs to be developed to keep the switch temperature at no higher than 80 °C during operation. This threshold is set due to an increase in electrical resistivity of silicon with an increase in temperature. This study compares the viability of two TMS, a microchannel and a jet impingement single-phase liquid system, to facilitate the long term operation of the switch for pulse power applications through performing computational fluid dynamic modeling (CFD) in ANSYS Fluent. The results from this study show that by utilizing a jet impingement system as TMS, the temperature of switch is maintained below the desired operating temperature when compared to that of the microchannel design under identical operating parameters (i.e., mass flow rate, coolant type and inlet temperature). Moreover, a cross validation of the thermal performance of the proposed systems has been made to further validate the obtained results.

scholarly journals Numerical Fatigue Analysis of a Prototype Francis Turbine Runner in Low-Load Operation

2019 ◽  
Vol 4 (3) ◽  
pp. 21 ◽  
Author(s):  
Julian Unterluggauer ◽  
Eduard Doujak ◽  
Christian Bauer
Keyword(s):  
Fatigue Damage ◽  
Power Plants ◽  
Response Times ◽  
Fluid Dynamic ◽  
Numerical Approach ◽  
Fast Response ◽  
Francis Turbine ◽  
Hydro Power ◽  
Hydraulic Machines ◽  
Low Load

Depending on a dynamical energy market dominated by the influence of volatile energies, the operators of hydro-power plants are forced to extend the operating range of their hydraulic machines to stay competitive. High flexibility towards low-load, a rising number of start-ups and fast response times are required for better control of the electrical grid. The major downside of these operating regions is that pressure pulsations, which are induced by the means of flow phenomena, lead to higher fatigue damage regarding the runner. Therefore, site measurements in combination with numerical methods can be used to gain a deeper understanding of the runner lifetime. This paper presents a numerical approach to understand the critical operation zones and access fatigue damage, including steady state, unsteady and transient computational fluid dynamic (CFD) one-way coupled with a transient finite element method (FEM).

scholarly journals CFD Modeling and Experimental Validation of an Alkaline Water Electrolysis Cell for Hydrogen Production

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1634
Author(s):  
Jesús Rodríguez ◽  
Ernesto Amores
Keyword(s):  
Fluid Dynamics ◽  
Hydrogen Production ◽  
Current Density ◽  
Fluid Dynamic ◽  
Water Electrolysis ◽  
Operating Conditions ◽  
Cfd Modeling ◽  
Electrolysis Cell ◽  
Alkaline Water Electrolysis ◽  
Alkaline Water

Although alkaline water electrolysis (AWE) is the most widespread technology for hydrogen production by electrolysis, its electrochemical and fluid dynamic optimization has rarely been addressed simultaneously using Computational Fluid Dynamics (CFD) simulation. In this regard, a two-dimensional (2D) CFD model of an AWE cell has been developed using COMSOL® software and then experimentally validated. The model involves transport equations for both liquid and gas phases as well as equations for the electric current conservation. This multiphysics approach allows the model to simultaneously analyze the fluid dynamic and electrochemical phenomena involved in an electrolysis cell. The electrical response was evaluated in terms of polarization curve (voltage vs. current density) at different operating conditions: temperature, electrolyte conductivity, and electrode-diaphragm distance. For all cases, the model fits very well with the experimental data with an error of less than 1% for the polarization curves. Moreover, the model successfully simulates the changes on gas profiles along the cell, according to current density, electrolyte flow rate, and electrode-diaphragm distance. The combination of electrochemical and fluid dynamics studies provides comprehensive information and makes the model a promising tool for electrolysis cell design.

Heat Transfer of Polymer Particles in Gas-Phase Polymerization Reactors

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Yaghoub Behjat ◽  
Mohammad Ali Dehnavi ◽  
Shahrokh Shahhosseini ◽  
Seyed Hassan Hashemabadi
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Gas Phase ◽  
Transfer Rate ◽  
Fluid Dynamic ◽  
Convective Heat Transfer Coefficient ◽  
Particle Surface ◽  
Cfd Modeling ◽  
Polymerization Reactor ◽  
Gas Phase Polymerization

In this paper the effects of particles configuration and particles distance on the heat transfer rate in a gas phase olefin polymerization reactor have been studied using the computational fluid dynamic (CFD) modeling approach. The goal was to determine the causes of particle overheating in this reactor. It has been shown that classic correlations such as Ranz-Marshall are sufficiently adequate when far away particles with no interactions are to be modeled. However, when particles are sufficiently close to having interactions, these correlations fail to satisfactorily predict the convective heat transfer coefficient. The results indicate an increase in particle distance leads to an increase in the Nusselt number on the particle surface. Therefore, for particles with a large distance and triangular or rotated square configurations, the local Nusselt number is closer to the Nusselt number for a single particle.

Benchmarking Computational Fluid Dynamics for Application to PWR Fuel

2002 ◽  
Author(s):  
L. D. Smith ◽  
M. E. Conner ◽  
B. Liu ◽  
B. Dzodzo ◽  
D. V. Paramonov ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Temperature Fields ◽  
Cfd Modeling ◽  
Spacer Grid ◽  
Cfd Models ◽  
Computational Mesh ◽  
Transfer Testing ◽  
Visualization Techniques

The present study demonstrates a process used to develop confidence in Computational Fluid Dynamics (CFD) as a tool to investigate flow and temperature distributions in a PWR fuel bundle. The velocity and temperature fields produced by a mixing spacer grid of a PWR fuel assembly are quite complex. Before using CFD to evaluate these flow fields, a rigorous benchmarking effort should be performed to ensure that reasonable results are obtained. Westinghouse has developed a method to quantitatively benchmark CFD tools against data at conditions representative of the PWR. Several measurements in a 5×5 rod bundle were performed. Lateral flowfield testing employed visualization techniques and Particle Image Velocimetry (PIV). Heat transfer testing involved measurements of the single-phase heat transfer coefficient downstream of the spacer grid. These test results were used to compare with CFD predictions. Among the parameters optimized in the CFD models based on this comparison with data include computational mesh, turbulence model, and boundary conditions. As an outcome of this effort, a methodology was developed for CFD modeling that provides confidence in the numerical results.

Mixing in Large Scale Tanks: Part IV — Cleaning Nuclear Waste From Tanks

Volume 4 ◽  
2004 ◽  
Author(s):  
Michael J. Augeri ◽  
Michael Hubbard ◽  
Jonathan L. Thomas
Keyword(s):  
Radioactive Waste ◽  
Nuclear Waste ◽  
Computational Fluid Dynamic ◽  
Large Scale ◽  
Fluid Dynamic ◽  
Field Conditions ◽  
Cfd Modeling ◽  
Velocity Modeling ◽  
Scale Modeling ◽  
Equipment Testing

The prototypical Advanced Design Mixer Pump (ADMP) was installed in the center of a nuclear waste tank to suspend settled solids, allowing removal of the solids from the tank with a separate transfer pump. Traditional waste removal methods use multiple (up to four) long shaft vertical pumps for suspending the waste solids. A combination of Computational Fluid Dynamic (CFD) modeling, scale modeling, and equipment testing was used to predict the capability of a single mixer pump to suspend radioactive waste solids in liquid using a forty mile per hour discharge jet velocity. Modeling and testing predicted the cleaning effectiveness of the mixer pump to ensure that the majority of waste solids throughout the tank would be suspended for removal to the extent technically and economically practical. In spite of unexpected field conditions and pump phenomena that hindered performance, observation showed that the pump performed as predicted by the modeling and testing.

scholarly journals Comparison of airborne measurements of NO, NO<sub>2</sub>, HONO, NO<sub>y</sub> and CO during FIREX-AQ

2022 ◽  
Author(s):  
Ilann Bourgeois ◽  
Jeff Peischl ◽  
J. Andrew Neuman ◽  
Steven S. Brown ◽  
Hannah M. Allen ◽  
...  
Keyword(s):  
Fluid Dynamic ◽  
Absorption Spectrometry ◽  
Fast Response ◽  
Tunable Diode Laser ◽  
Organic Nitrates ◽  
Ionization Mass ◽  
Fire Plume ◽  
Airborne Measurements ◽  
Sampling Fraction ◽  
Highly Correlated

Abstract. We present a comparison of fast-response instruments installed onboard the NASA DC-8 aircraft that measured nitrogen oxides (NO and NO2), nitrous acid (HONO), total reactive odd nitrogen (measured both as the total (NOy) and from the sum of individually measured species (SNOy)) and carbon monoxide (CO) in the troposphere during the 2019 Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) campaign. By targeting smoke from summertime wildfires, prescribed fires and agricultural burns across the continental United States, FIREX-AQ provided a unique opportunity to investigate measurement accuracy in concentrated plumes where hundreds of species coexist. Here, we compare NO measurements by chemiluminescence (CL) and laser induced fluorescence (LIF); NO2 measurements by CL, LIF and cavity enhanced spectroscopy (CES); HONO measurements by CES and iodide-adduct chemical ionization mass spectrometry (CIMS); and CO measurements by tunable diode laser absorption spectrometry (TDLAS) and integrated cavity output spectroscopy (ICOS). Additionally, total NOy measurements using the CL instrument were compared with SNOy (= NO + NO2 + HONO + nitric acid (HNO3) + acyl peroxy nitrates (APNs) + submicron particulate nitrate (pNO3)). The aircraft instrument intercomparisons demonstrate the following: 1) NO measurements by CL and LIF agreed well within instrument uncertainties, but with potentially reduced time response for the CL instrument; 2) NO2 measurements by LIF and CES agreed well within instrument uncertainties, but CL NO2 was on average 10 % higher; 3) CES and CIMS HONO measurements were highly correlated in each fire plume transect, but the correlation slope of CES vs. CIMS for all 1 Hz data during FIREX-AQ was 1.8, which we attribute to a reduction in the CIMS sensitivity to HONO in high temperature environments; 4) NOy budget closure was demonstrated for all flights within the combined instrument uncertainties of 25 %. However, we used a fluid dynamic flow model to estimate that average pNO3 sampling fraction through the NOy inlet in smoke was variable from one flight to another and ranged between 0.36 and 0.99, meaning that approximately 0–24 % on average of the total measured NOy in smoke may have been unaccounted for and may be due to unmeasured species such as organic nitrates; 5) CO measurements by ICOS and TDLAS agreed well within combined instrument uncertainties, but with a systematic offset that averaged 2.87 ppbv; and 6) integrating smoke plumes followed by fitting the integrated values of each plume improved the correlation between independent measurements.

Aero-Shields: New Product Improves Boiler Performance and Maintenance

2012 ◽  
Author(s):  
Greg Epelbaum ◽  
Eric Tanguay
Keyword(s):  
Heat Transfer ◽  
Solid Waste ◽  
Gas Flow ◽  
Fluid Dynamic ◽  
Flow Distribution ◽  
Field Testing ◽  
Design Guidelines ◽  
Cfd Modeling ◽  
Development Effort ◽  
Lee County

Aero-Shields were developed by Covanta Energy in 2005 to address excessive fouling and accelerated tube metal wastage in certain heat transfer areas of a large Municipal Solid Waste (MSW) fired boiler. Computational Fluid Dynamic (CFD) modeling and a Cold Flow model were used to investigate flue gas flow distribution, velocities, temperatures, and other parameters in specific areas of the boiler. The intent of this effort was to identify the problematic areas and develop a solution to better distribute gas flow within these specific areas of the boiler. The result of this development effort was named “Aero-Shield”. The Aero-Shield provides a dual benefit of being a tube-shield and gas baffling device by incorporating extended tapered sides. The shape, size and installation location was developed through the use of CFD modeling. Initial testing of the shields was performed in December 2005 at the Lee County facility Boiler#2 at the top and bottom of the third pass. The Lee County boiler is a typical horizontal boiler design using Martin GMBH technology to process solid waste. This paper demonstrates how CFD modeling plays an extremely important role in designing and optimizing Aero-Shields for new applications. It also describes additional applications which have been tested in multiple facilities and boilers types since 2005. It covers design guidelines for the material, geometry, and installation procedure. The paper will also highlight a number of benefits which have been confirmed through extensive field testing which include: • Significant heat transfer increase in a targeted boiler area. This increases boiler efficiency and generates additional MWs at the same fuel rate. • In Energy-from-Waste (EfW) applications, capital and maintenance costs are often more important than saving fuel. Aero-Shield applications provide significant savings by requiring less heat surface for the same heat recovery in a targeted boiler component. • Reduced ash deposits which results in reduced maintenance. • Improved gas flow distribution allows Aero-Shields to reduce peak gas temperatures and velocities, resulting in lower wastage rates for critical boiler components. • Simple, quick, and economical installation: typically performed in a few hours. Covanta currently has a patent pending on this application and product. Additional testing is ongoing to address other areas within the boiler that may benefit from this technology recognizing that the “Aero-Shield” is a customized solution for each application.

scholarly journals Experimental Analysis and CFD Modeling for Conventional Basin-Type Solar Still

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5734
Author(s):  
Mahmoud S. El-Sebaey ◽  
Asko Ellman ◽  
Ahmed Hegazy ◽  
Tarek Ghonim
Keyword(s):  
Fresh Water ◽  
Water Depth ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Cfd Modeling ◽  
Solar Still ◽  
Cfd Model ◽  
Climate Conditions ◽  
Experimental Values ◽  
Multi Phase

With the rising population, environmental pollution, and social development, potable water is reducing and being contaminated day by day continually. Thus, several researchers have focused their studies on seas and oceans in order to get potable fresh water by desalination of their saltwater. Solar still of basin type is one of the available technologies to purify water because of free solar energy. The computational fluid dynamic CFD model of the solar still can significantly improve means for optimization of the solar still structure because it reduces the need for conducting large amount of experiments. Therefore, the main purpose of this study is presenting a multi-phase, three-dimensional CFD model, which predicts the performance of the solar still without using any experimental measurements, depending on the CFD solar radiation model. Simulated results are compared with experimental values of water and glass cover temperatures and yield of fresh water in climate conditions of Sheben El-Kom, Egypt (latitude 30.5° N and longitude 31.01° E). The simulation results were found to be in acceptable agreement with the experimental measured data. The results indicated that the daily simulated and experimental accumulated productivities of the single-slope solar still were found to be 1.982 and 1.785 L/m2 at a water depth of 2 cm. In addition, the simulated and experimental daily efficiency were around 16.79% and 15.5%, respectively, for the tested water depth.

Burner Component Upgrades for Wall-Fired Coal Burners: RPI Results and Experiences

2011 ◽  
Author(s):  
Stephen W. Black ◽  
Murat Yaldizli
Keyword(s):  
Second Generation ◽  
Fluid Dynamic ◽  
Cost Effective ◽  
Operating Conditions ◽  
Cfd Modeling ◽  
Nox Emissions ◽  
Effective Components ◽  
Utility Companies ◽  
Boiler Operation ◽  
First And Second Generation

Improving the operation and emissions performance of coal fired utility boilers equipped with first and second-generation wall fired low NOx coal burners is of significant interest to many utility companies today. The recent development of cost effective components for existing first and second-generation wall fired burners permits better combustion performance, increased wear life reliability, and decreased NOx emissions. Existing air register systems can typically remain in place, resulting in reduced capital cost and reduced outage time for installation. Computational fluid dynamic (CFD) modeling is used to assist in the design of key burner components and operating conditions that enable further reduction of NOx emissions. Results include better flame attachment, better airflow recirculation patterns, and early ignition and pyrolysis of the coal in a more controlled primary combustion zone. NOx reductions of 10–20% have been demonstrated using burner component upgrades with improved overall boiler operation. This paper gives a brief description of the component-only retrofit design methodology that Riley Power Inc., a Babcock Power Inc. company developed for other OEM’s low NOx burners in wall-fired furnaces. The numerical modeling to assist in the design of these low NOx systems and the corresponding CFD results are also discussed.

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