scholarly journals Mathematical Modelling for Furnace Design Refining Molten Aluminum

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1798
Author(s):  
Alfredo Alan Flores Saldívar ◽  
Rodrigo Juárez Martínez ◽  
Alfredo Flores Valdés ◽  
Jesús Torres Torres ◽  
Rocío Maricela Ochoa Palacios ◽  
...  
Keyword(s):  
Mathematical Modelling ◽  
Melting Furnace ◽  
Temperature Profiles ◽  
Complex Flow ◽  
Optimal Position ◽  
Combustion Gases ◽  
Physical Experiments ◽  
Simulation Based ◽  
Final Design ◽  
Magnesium Removal

The design of an aluminium melting furnace has faced two challenges: mathematical modelling and simulative optimization. This paper first uses fluid dynamics to model the aluminium process mathematically. Then, the model is utilized to simulate a round shaped reverberatory furnace for melting aluminium alloys. In order to achieve the highest thermal efficiency of the furnace, modelling and simulation are performed to predict complex flow patterns, geometries, temperature profiles of the mixture-gas air through the main chamber, as well as the melting tower attached to the furnace. The results led to the establishment of optimal position and angle of the burner, which are validated through physical experiments, ensuring recirculation of the combustion gases through the melting chamber and the melting tower. Furthermore, a proper arrangement of refractory materials is derived to avoid heat losses through the outer surface of the furnace. Temperature profiles are also determined for the optimization to arrive at the final design of the furnace. Compared with manual designs previously practiced, the simulation-based optimal design of furnaces offers excellent guidance, an increase in the aluminium processing and magnesium removal for more refined alloys, and an increased processing rate of aluminium chip accession.

CPI Stress Induced Carrier Mobility Shift in Advanced Silicon Nodes

2016 ◽  
Author(s):  
Valeriy Sukharev ◽  
Jun-Ho Choy ◽  
Armen Kteyan ◽  
Henrik Hovsepyan ◽  
Uwe Muehle ◽  
...  
Keyword(s):  
Electrical Characterization ◽  
Compact Modeling ◽  
Electrical Characteristics ◽  
Mobility Shift ◽  
Physical Strain ◽  
Multi Scale ◽  
Modeling Methodology ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Final Design

Potential challenges with managing mechanical stress and the consequent effects on device performance for advanced 3D IC technologies are outlined. The growing need for a simulation-based design verification flow capable of analyzing and detecting across-die out-of-spec stress-induced variations in MOSFET/FinFET electrical characteristics is highlighted. A physics-based compact modeling methodology for multi-scale simulation of all contributing components of stress induced variability is described. A simulation flow that provides an interface between layout formats (GDS II, OASIS), and FEA-based package-scale tools, is also developed. This tool, can be used to optimize the floorplan for different circuits and packaging technologies, and/or for the final design signoff, for all stress induced phenomena. Finally, a calibration technique based on fitting to measured electrical characterization data is presented, along with correlation of the electrical characteristics to direct physical strain measurements.

Separated Flows Around the Rear Window of a Simplified Car Geometry

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Mathieu Rouméas ◽  
Patrick Gilliéron ◽  
Azeddine Kourta
Keyword(s):  
Blunt Body ◽  
Wake Flow ◽  
Complex Flow ◽  
Flow Topology ◽  
Rear Window ◽  
Near Wake ◽  
Longitudinal Vortices ◽  
Simulation Based ◽  
Aerodynamic Performances ◽  
Boltzmann Method

A 3D numerical simulation based on the lattice Boltzmann method is carried out on a simplified car geometry (initially proposed by Ahmed, Ramm, and Falting, 1984, SAE Technical Paper series No. 840300) to analyze and establish a method for controlling the near-wake flow topology of a generic blunt body model. The results indicate the existence of a complex flow topology consisting of transverse and longitudinal vortices emanating from flow separations that occur on the top and the lateral edges of the slanted rear window, respectively. The topology of each structure is detailed and the numerical results are compared with the experimental results in the literature. The results presented in this paper can then be used to develop and parametrize active control solutions conducive to improving the aerodynamic performances of automobile vehicles.

What is the Ideal Glass Bath Depth of a Glass Furnace?

2008 ◽  
Vol 39-40 ◽  
pp. 447-452
Author(s):  
H.P.H. Muijsenberg ◽  
Marketa Muijsenberg ◽  
J. Chmelar
Keyword(s):  
Energy Efficiency ◽  
Temperature Distribution ◽  
Mathematical Modelling ◽  
Glass Industry ◽  
Life Time ◽  
Furnace Design ◽  
Glass Quality ◽  
Extra Effort ◽  
Final Design ◽  
The Ideal

Mathematical modelling is reaching a high acceptance level within the glass industry. Today most new furnaces are being modelled before the final design is decided. It is clear that the modelling helps to optimise the furnace in respect to glass quality, energy efficiency and furnace life-time. The extra effort of the modelling is leading for sure to a quick pay-back of this extra investment and an increased profit over the furnace life-time. Even the furnace life-time can be extended with better insight on temperature distribution and glass speeds that corrode the refractory. Many glass produces are always asking us: “what is the optimal glass depth”? There is not just one answer to this, but the paper demonstrates how mathematical modelling can help to find the optimal furnace depth for a certain furnace design.

Numerical Simulation of Ship Maneuvering on Bend Channel

2012 ◽  
Vol 204-208 ◽  
pp. 4578-4585
Author(s):  
Bing Jiang Dong ◽  
Jiang Lin ◽  
Qian Chen
Keyword(s):  
Flow Simulation ◽  
Great Difficulty ◽  
Scientific Basis ◽  
Flow Conditions ◽  
Complex Flow ◽  
3D Flow ◽  
Ship Maneuvering ◽  
Inland Waterways ◽  
Simulation Based ◽  
Bend Channel

Bend channel is common seen in inland waterways. Due to the complex flow conditions, it’s often of great difficulty for ship maneuvering. To improve navigation conditions, usually the regulation is needed. In this paper, a 3D flow simulation model and ship maneuvering model are coupled. Based on the simulation results, the navigation conditions in Yiyang-Lulintan waterway project are evaluated. The simulation based evaluation provides a scientific basis and guidance for regulation projects in bend channel.

scholarly journals The Significance of Vertical and Lateral Groundwater–Surface Water Exchange Fluxes in Riverbeds and Riverbanks: Comparing 1D Analytical Flux Estimates with 3D Groundwater Modelling

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 306
Author(s):  
Gert Ghysels ◽  
Christian Anibas ◽  
Henock Awol ◽  
Abebe Debele Tolche ◽  
Uwe Schneidewind ◽  
...  
Keyword(s):  
Water Exchange ◽  
Vertical Flux ◽  
Temperature Profiles ◽  
Vertical Flow ◽  
Groundwater Model ◽  
Complex Flow ◽  
Heterogeneous Structures ◽  
Spatially Distributed ◽  
Heat Transport Equation ◽  
Exchange Flux

Riverbed temperature profiles are frequently used to estimate vertical river–aquifer exchange fluxes. Often in this approach, strictly vertical flow is assumed. However, riverbeds are heterogeneous structures often characterised by complex flow fields, possibly violating this assumption. We characterise the meter-scale variability of river–aquifer interaction at two sections of the Aa River, Belgium, and compare vertical flux estimates obtained with a 1D analytical solution to the heat transport equation with fluxes simulated with a 3D groundwater model (MODFLOW) using spatially distributed fields of riverbed hydraulic conductivity. Based on 115 point-in-time riverbed temperature profiles, vertical flux estimates that are obtained with the 1D solution are found to be higher near the banks than in the center of the river. The total exchange flux estimated with the 3D groundwater model is around twice as high as the estimate based on the 1D solution, while vertical flux estimates from both methods are within a 10% margin. This is due to an important contribution of non-vertical flows, especially through the riverbanks. Quasi-vertical flow is only found near the center of the river. This quantitative underestimation should be considered when interpreting exchange fluxes based on 1D solutions. More research is necessary to assess conditions for which using a 1D analytical approach is justified to more accurately characterise river–aquifer exchange fluxes.

scholarly journals Handling Perception Uncertainty in Simulation-Based Singulation Planning for Robotic Bin Picking

2018 ◽  
Vol 18 (2) ◽  
Author(s):  
Nithyananda B. Kumbla ◽  
Shantanu Thakar ◽  
Krishnanand N. Kaipa ◽  
Jeremy Marvel ◽  
Satyandra K. Gupta
Keyword(s):  
Real Time ◽  
Completion Time ◽  
Task Completion ◽  
Computationally Efficient ◽  
Task Completion Time ◽  
Physical Experiments ◽  
Perception System ◽  
Simulation Based ◽  
Probability Of Success ◽  
Bin Picking

Robotic bin picking requires using a perception system to estimate the posture of parts in the bin. The selected singulation plan should be robust with respect to perception uncertainties. If the estimated posture is significantly different from the actual posture, then the singulation plan may fail during execution. In such cases, the singulation process will need to be repeated. We are interested in selecting singulation plans that minimize the expected task completion time. In order to estimate the expected task completion time for a proposed singulation plan, we need to estimate the probability of success and the plan execution time. Robotic bin picking needs to be done in real-time. Therefore, candidate singulation plans need to be generated and evaluated in real-time. This paper presents an approach for utilizing computationally efficient simulations for generating singulation plans. Results from physical experiments match well with the predictions obtained from simulations.

Simulation Based On-Line Evaluation of Singulation Plans to Handle Perception Uncertainty in Robotic Bin Picking

2017 ◽  
Author(s):  
Nithyananda B. Kumbla ◽  
Shantanu Thakar ◽  
Krishnanand N. Kaipa ◽  
Jeremy Marvel ◽  
Satyandra K. Gupta
Keyword(s):  
Real Time ◽  
Completion Time ◽  
Task Completion ◽  
Computationally Efficient ◽  
Task Completion Time ◽  
Physical Experiments ◽  
Perception System ◽  
Simulation Based ◽  
Bin Picking ◽  
On Line

Robotic bin picking requires using a perception system to estimate the posture of parts in the bin. The selected singulation plan should be robust with respect to perception uncertainties. If the estimated posture is significantly different from the actual posture, then the singulation plan may fail during execution. In such cases, the singulation process will need to be repeated. We are interested in selecting singulation plans that minimize the expected task completion time. In order to estimate the expected task completion time for a proposed singulation plan, we need to estimate the probability of success and the plan execution time. Robotic bin picking needs to be done in real-time. Therefore candidate singulation plans need to be generated and evaluated in real-time. This paper presents an approach for utilizing computationally efficient simulations for on-line evaluation of singulation plans. Results from physical experiments match well with predictions obtained from simulations.

Numerical Study of the Flow and Temperature Distributions in a 350 MW Utility Boiler

2010 ◽  
Author(s):  
Iva´n F. Galindo-Garci´a ◽  
Ana Karenina Va´zquez Barraga´n ◽  
Miguel Rossano Roma´n
Keyword(s):  
Numerical Study ◽  
Mean Flow ◽  
Complex Flow ◽  
Total Load ◽  
Utility Boiler ◽  
Flow Equations ◽  
Combustion Gases ◽  
Temperature Distributions ◽  
Porous Media Model ◽  
High Reynolds

A computational model is developed in order to analyze flow, temperature and species distributions inside a 350 MW utility boiler. It is assumed that identification of high temperature or high velocity zones will help in the prevention of failures in the boiler walls, superheaters, reheaters and economizers. For the analysis of these failures the modeling of the chemical and physical phenomena inside the boiler is important, because one of the known causes of tube failure is the non-uniform heating of the tubes, which strongly depends on the combustion gases flow and temperature distributions. The 3-D computational fluid dynamics (CFD) codes provide an effective tool for this type of calculations. CFD calculations were performed for the condition of 100% of total load for a 350 MW utility boiler using either pulverized coal or heavy oil as fuels. The CFD calculations adopt a 3D-formulation of the mean flow equations in combination with the standard high-Reynolds-number k-epsilon turbulence model and a probability density function to model fuel combustion. The tube banks are represented by a porous media model. Comparisons between calculations and key global parameters from the power plant show relatively good agreement. Velocity profiles show a very complex flow in the boiler, especially in the lower part of the boiler, where the injected streams form a cyclone at the center of the boiler.

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