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Steven Lottes

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Papers by Steven Lottes

The Effect of Particle Inlet Conditions on FCC Riser Hydrodynamics and Product Yields

Heat Transfer: Volume 2, 1999

Essential to today’s modern refineries and the gasoline production process are fluidized catalyti... more Essential to today’s modern refineries and the gasoline production process are fluidized catalytic cracking units. By using a computational fluid dynamics (CFD) code developed at Argonne National Laboratory to simulate the riser, parametric and sensitivity studies were performed to determine the effect of catalyst inlet conditions on the riser hydrodynamics and on the product yields. Simulations were created on the basis of a general riser configuration and operating conditions. The results of this work are indications of riser operating conditions that will maximize specific product yields. The CFD code is a three-dimensional, multiphase, turbulent, reacting flow code with phenomenological models for particle-solid interactions, droplet evaporation, and chemical kinetics. The code has been validated against pressure, particle loading, and product yield measurements. After validation of the code, parametric studies were performed on various parameters such as the injection velocity ...

Scour Estimation for Tsunami at Bridges

The World of Tomorrow Is Today

Public roads, 2016

Computational fluid dynamics and computational structural mechanics now are routinely employed in... more Computational fluid dynamics and computational structural mechanics now are routinely employed in the design of vehicles, ships, and aircraft. The successful application of modern computational mechanics in a wide variety of industries suggests that it can and should be applied to transportation research and development. This article describes several recent and current examples of applied research that illustrate how FHWA and Argonne National Laboratory’s Transportation Research and Analysis Computing Center researchers are using high-performance computer clusters and computational mechanics to help solve transportation infrastructure problems, assess risks, and improve designs.

Three Dimensional Computational Fluid Dynamics Analysis to Determine Flow Capacity of an ADA Compliant Street Drain Grate

Development of CFD simulation for 3-D flooding flow and scouring around a bridge structure

Analysis of drag and lift forces and evaluation of scour around bridge structures are necessary t... more Analysis of drag and lift forces and evaluation of scour around bridge structures are necessary to assess risk of bridge failure during storms and floods. Simulation of scour-hole formation under the bridge deck and around the bridge piers, due to sediment entrainment and transport caused by flooding flow conditions, is of significant interest to computational fluid dynamics (CFD) and hydraulics researchers. This study is focused on simulation of 3-D open channel turbulent flow over an inundated bridge deck to obtain the final shape and size of the scour-hole. This 3-D study extends the previous 2-D simulation scouring methodology. Solutions for flow field and turbulence, using an effective bed roughness value, are based on the Reynolds Averaged Navier-Stokes (RANS) equations, and a k– turbulence closure model using a commercial CFD code. An iterative computational methodology is developed to predict the equilibrium 3-D scour-hole using a single phase model moving boundary formulat...

Advanced Methodology to Assess Riprap Rock Stability at Bridge Piers and Abutments

CFD Modeling of Rockery Walls in the River Environment

A computational approach to the study of the stability of pier riprap at the Middle Fork Feather River

Scour and Erosion, Aug 29, 2016

This paper discusses the use of various technologies and advanced computational modeling techniqu... more This paper discusses the use of various technologies and advanced computational modeling techniques that were combined for monitoring the performance of pier riprap on the basis of a field case study-Pier 3 of a bridge over the Middle Fork Feather River-in northern California, USA. The first phase involved capturing the field condition of the bridge site using sonar instrumentation technology in order to obtain high resolution bathymetry data. The second phase entailed enhancement and transformation of the scanned bathymetric data into a 3D CAD model to be used as the initial geometry for numerical modeling. A Fluid Structure Interaction (FSI) numerical approach was applied to simulate the rock incipient motion i.e. shear failure by coupling Computational Fluid Dynamics (CFD) software STAR-CCM+ and a Computational Structural Mechanics (CSM) software LS-DYNA. Several coupled simulations have been performed with varying flow conditions to identify shear failure conditions for the riprap apron.

Three-Dimensional Flow Analysis Methodology for Assessing Stream Stability and Channel Migration

Hydraulic Study of the South Carolina DOT Catch Basin Type 25

Modeling of Water Film Formation on a Stay-Cable

CFD-DEM Onset of Motion Analysis for Application to Bed Scour Risk Assessment

Development of a Computational Approach to Detect Instability and Incipient Motion of Large Riprap Rocks

Dynamic fuel processor with controlled declining temperatures

Current Applications of Computational Fluid Dynamics to Hydraulic Problems in FHWA R & D at Argonne's Transportation Research and Analysis Computing Center

CFD Modeling of Rockery Walls in the River Environment

Computational Modeling of Industrial Scale Reactor System Components Using Parallel Processing on a Networked Cluster of Computers

Energy Conversion and Resources: Fuels and Combustion Technology, Energy, Nuclear Engineering, and Solar Engineering, 2003

Industrial scale reactor system components are frequently characterized by a complex geometry tha... more Industrial scale reactor system components are frequently characterized by a complex geometry that requires a large number of nodes in a computational grid to resolve significant flow features and by reaction and additional complex physics, such as spray vaporization, that greatly increase the number of partial differential equations (PDEs) to solve. On a fast serial workstation, simulations of these systems can take several days, making use of the model for extensive parametric and optimization studies impractical. A parallel multiphase reacting flow code was developed from a family of related serial codes using the industry standard Message-Passing Interface (MPI) and domain decomposition in the primary flow direction. The parallel computational fluid dynamics (CFD) code can now be run on a cluster of networked computers. This capability makes detailed simulation of many industrial reactors feasible without incurring the large increase in cost of moving to simulation on massively ...

Hydraulic Capacity of an ADA Compliant Street Drain Grate

Resurfacing of urban roads with concurrent repairs and replacement of sections of curb and sidewa... more Resurfacing of urban roads with concurrent repairs and replacement of sections of curb and sidewalk may require pedestrian ramps that are compliant with the American Disabilities Act (ADA), and when street drains are in close proximity to the walkway, ADA compliant street grates may also be required. The Minnesota Department of Transportation ADA Operations Unit identified a foundry with an available grate that meets ADA requirements. Argonne National Laboratory’s Transportation Research and Analysis Computing Center used full scale three dimensional computational fluid dynamics to determine the performance of the ADA compliant grate and compared it to that of a standard vane grate. Analysis of a parametric set of cases was carried out, including variation in longitudinal, gutter, and cross street slopes and the water spread from the curb. The performance of the grates was characterized by the fraction of the total volume flow approaching the grate from the upstream that was captured by the grate and diverted into the catch basin. The fraction of the total flow entering over the grate from the side and the fraction of flow directly over a grate diverted into the catch basin were also quantities of interest that aid in understanding the differences in more » performance of the grates. The ADA compliant grate performance lagged that of the vane grate, increasingly so as upstream Reynolds number increased. The major factor leading to the performance difference between the two grates was the fraction of flow directly over the grates that is captured by the grates. « less

A study of the spray injection Reynolds number effects on gasoline yields of an FCC riser reactor

A computational analysis of the combined effects of feed oil injection parameters in a commercial... more A computational analysis of the combined effects of feed oil injection parameters in a commercial-scale fluidized catalytic cracking riser reactor was performed using a three-phase, multiple species kinetic cracking computer code. The analysis showed that the injection operating parameters (droplet diameter and injection velocity) had strong impacts on the gasoline yields of the FCC unit. A spray injection Reynolds number combining the two parameters was defined. A correlation between the spray injection Reynolds number and the gasoline product yields for various feed injection conditions was developed. A range of spray injection Reynolds number for the maximum gasoline yield was identified.

Effects of copper catalytic reactions on the development of supersonic hydrogen flames

Copper species are present in hydrogen flames in arc heated supersonic ramjet testing facilities.... more Copper species are present in hydrogen flames in arc heated supersonic ramjet testing facilities. Homogeneous and heterogeneous copper catalytic reactions may affect the flame development by enhancing the recombination of hydrogen atoms. Computer simulation is used to investigate the effects of the catalytic reactions on the reaction and ignition times of the flames. The simulation uses a modified general chemical kinetics computer program to simulate the development of copper-contaminated hydrogen flames under scramjet testing conditions. Reaction times of hydrogen flames are found to be reduced due to the copper catalytic effects, but ignition times are much less sensitive to such effects. The reduction of reaction time depends on copper concentration, particle size (if copper is in the condensed phase), and Mach number (or initial temperature and pressure). As copper concentration increases or the particle size decreases, reaction time decreases. As Mach number increases (or pres...

The Effect of Particle Inlet Conditions on FCC Riser Hydrodynamics and Product Yields

Heat Transfer: Volume 2, 1999

Essential to today’s modern refineries and the gasoline production process are fluidized catalyti... more Essential to today’s modern refineries and the gasoline production process are fluidized catalytic cracking units. By using a computational fluid dynamics (CFD) code developed at Argonne National Laboratory to simulate the riser, parametric and sensitivity studies were performed to determine the effect of catalyst inlet conditions on the riser hydrodynamics and on the product yields. Simulations were created on the basis of a general riser configuration and operating conditions. The results of this work are indications of riser operating conditions that will maximize specific product yields. The CFD code is a three-dimensional, multiphase, turbulent, reacting flow code with phenomenological models for particle-solid interactions, droplet evaporation, and chemical kinetics. The code has been validated against pressure, particle loading, and product yield measurements. After validation of the code, parametric studies were performed on various parameters such as the injection velocity ...

Scour Estimation for Tsunami at Bridges

The World of Tomorrow Is Today

Public roads, 2016

Computational fluid dynamics and computational structural mechanics now are routinely employed in... more Computational fluid dynamics and computational structural mechanics now are routinely employed in the design of vehicles, ships, and aircraft. The successful application of modern computational mechanics in a wide variety of industries suggests that it can and should be applied to transportation research and development. This article describes several recent and current examples of applied research that illustrate how FHWA and Argonne National Laboratory’s Transportation Research and Analysis Computing Center researchers are using high-performance computer clusters and computational mechanics to help solve transportation infrastructure problems, assess risks, and improve designs.

Three Dimensional Computational Fluid Dynamics Analysis to Determine Flow Capacity of an ADA Compliant Street Drain Grate

Development of CFD simulation for 3-D flooding flow and scouring around a bridge structure

Analysis of drag and lift forces and evaluation of scour around bridge structures are necessary t... more Analysis of drag and lift forces and evaluation of scour around bridge structures are necessary to assess risk of bridge failure during storms and floods. Simulation of scour-hole formation under the bridge deck and around the bridge piers, due to sediment entrainment and transport caused by flooding flow conditions, is of significant interest to computational fluid dynamics (CFD) and hydraulics researchers. This study is focused on simulation of 3-D open channel turbulent flow over an inundated bridge deck to obtain the final shape and size of the scour-hole. This 3-D study extends the previous 2-D simulation scouring methodology. Solutions for flow field and turbulence, using an effective bed roughness value, are based on the Reynolds Averaged Navier-Stokes (RANS) equations, and a k– turbulence closure model using a commercial CFD code. An iterative computational methodology is developed to predict the equilibrium 3-D scour-hole using a single phase model moving boundary formulat...

Advanced Methodology to Assess Riprap Rock Stability at Bridge Piers and Abutments

CFD Modeling of Rockery Walls in the River Environment

A computational approach to the study of the stability of pier riprap at the Middle Fork Feather River

Scour and Erosion, Aug 29, 2016

This paper discusses the use of various technologies and advanced computational modeling techniqu... more This paper discusses the use of various technologies and advanced computational modeling techniques that were combined for monitoring the performance of pier riprap on the basis of a field case study-Pier 3 of a bridge over the Middle Fork Feather River-in northern California, USA. The first phase involved capturing the field condition of the bridge site using sonar instrumentation technology in order to obtain high resolution bathymetry data. The second phase entailed enhancement and transformation of the scanned bathymetric data into a 3D CAD model to be used as the initial geometry for numerical modeling. A Fluid Structure Interaction (FSI) numerical approach was applied to simulate the rock incipient motion i.e. shear failure by coupling Computational Fluid Dynamics (CFD) software STAR-CCM+ and a Computational Structural Mechanics (CSM) software LS-DYNA. Several coupled simulations have been performed with varying flow conditions to identify shear failure conditions for the riprap apron.

Three-Dimensional Flow Analysis Methodology for Assessing Stream Stability and Channel Migration

Hydraulic Study of the South Carolina DOT Catch Basin Type 25

Modeling of Water Film Formation on a Stay-Cable

CFD-DEM Onset of Motion Analysis for Application to Bed Scour Risk Assessment

Development of a Computational Approach to Detect Instability and Incipient Motion of Large Riprap Rocks

Dynamic fuel processor with controlled declining temperatures

Current Applications of Computational Fluid Dynamics to Hydraulic Problems in FHWA R & D at Argonne's Transportation Research and Analysis Computing Center

CFD Modeling of Rockery Walls in the River Environment

Computational Modeling of Industrial Scale Reactor System Components Using Parallel Processing on a Networked Cluster of Computers

Energy Conversion and Resources: Fuels and Combustion Technology, Energy, Nuclear Engineering, and Solar Engineering, 2003

Industrial scale reactor system components are frequently characterized by a complex geometry tha... more Industrial scale reactor system components are frequently characterized by a complex geometry that requires a large number of nodes in a computational grid to resolve significant flow features and by reaction and additional complex physics, such as spray vaporization, that greatly increase the number of partial differential equations (PDEs) to solve. On a fast serial workstation, simulations of these systems can take several days, making use of the model for extensive parametric and optimization studies impractical. A parallel multiphase reacting flow code was developed from a family of related serial codes using the industry standard Message-Passing Interface (MPI) and domain decomposition in the primary flow direction. The parallel computational fluid dynamics (CFD) code can now be run on a cluster of networked computers. This capability makes detailed simulation of many industrial reactors feasible without incurring the large increase in cost of moving to simulation on massively ...

Hydraulic Capacity of an ADA Compliant Street Drain Grate

Resurfacing of urban roads with concurrent repairs and replacement of sections of curb and sidewa... more Resurfacing of urban roads with concurrent repairs and replacement of sections of curb and sidewalk may require pedestrian ramps that are compliant with the American Disabilities Act (ADA), and when street drains are in close proximity to the walkway, ADA compliant street grates may also be required. The Minnesota Department of Transportation ADA Operations Unit identified a foundry with an available grate that meets ADA requirements. Argonne National Laboratory’s Transportation Research and Analysis Computing Center used full scale three dimensional computational fluid dynamics to determine the performance of the ADA compliant grate and compared it to that of a standard vane grate. Analysis of a parametric set of cases was carried out, including variation in longitudinal, gutter, and cross street slopes and the water spread from the curb. The performance of the grates was characterized by the fraction of the total volume flow approaching the grate from the upstream that was captured by the grate and diverted into the catch basin. The fraction of the total flow entering over the grate from the side and the fraction of flow directly over a grate diverted into the catch basin were also quantities of interest that aid in understanding the differences in more » performance of the grates. The ADA compliant grate performance lagged that of the vane grate, increasingly so as upstream Reynolds number increased. The major factor leading to the performance difference between the two grates was the fraction of flow directly over the grates that is captured by the grates. « less

A study of the spray injection Reynolds number effects on gasoline yields of an FCC riser reactor

A computational analysis of the combined effects of feed oil injection parameters in a commercial... more A computational analysis of the combined effects of feed oil injection parameters in a commercial-scale fluidized catalytic cracking riser reactor was performed using a three-phase, multiple species kinetic cracking computer code. The analysis showed that the injection operating parameters (droplet diameter and injection velocity) had strong impacts on the gasoline yields of the FCC unit. A spray injection Reynolds number combining the two parameters was defined. A correlation between the spray injection Reynolds number and the gasoline product yields for various feed injection conditions was developed. A range of spray injection Reynolds number for the maximum gasoline yield was identified.

Effects of copper catalytic reactions on the development of supersonic hydrogen flames

Copper species are present in hydrogen flames in arc heated supersonic ramjet testing facilities.... more Copper species are present in hydrogen flames in arc heated supersonic ramjet testing facilities. Homogeneous and heterogeneous copper catalytic reactions may affect the flame development by enhancing the recombination of hydrogen atoms. Computer simulation is used to investigate the effects of the catalytic reactions on the reaction and ignition times of the flames. The simulation uses a modified general chemical kinetics computer program to simulate the development of copper-contaminated hydrogen flames under scramjet testing conditions. Reaction times of hydrogen flames are found to be reduced due to the copper catalytic effects, but ignition times are much less sensitive to such effects. The reduction of reaction time depends on copper concentration, particle size (if copper is in the condensed phase), and Mach number (or initial temperature and pressure). As copper concentration increases or the particle size decreases, reaction time decreases. As Mach number increases (or pres...