bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Modeling Approaches for Open-Fire Hearth Furnace Heat Transfer
Authors: Kurzawski Andrew , Ezekoye Ofodike A. , Baldea Michael , Edgar Thomas F. 
Published: March 2016

Modeling of heat transfer processes for controls applications requires that the modeler make a set of assumptions that strikes a balance between accuracy and simulation run time. Common points of consideration include choosing the appropriate dimension of the model, the importance of transient effects, numerical and temporal discretization, etc. The results of these decisions directly impact the speed and accuracy of the model. It can be useful for the modeler to build a framework containing a set of models for a given system where each model contains a different set assumptions. This allows for easy comparison of different classes of models and aids in the decision process for selecting the model that best fits the needs of the user.
This work takes the modeling of an open-flame hearth furnace as a case study and examines the implications of different modeling simplifications. This scenario is similar to plug-flow reactors (PFRs) and continuous stirred-tank reactors (CSTRs) in that reactions are occurring in a chamber where mass is flowing in to and out of the system. Modeling of these systems focuses on the concentration of the reactants, whereas the hearth furnace model seeks to capture the heat transfer to the work-piece and walls. Numerous models of PRFs and CSTRs exist in literature as well as several open-fire furnace models using Hottel’s zone method. This work builds off of these modeling techniques by testing several types of models for speed and accuracy.
Both steady-state and transient operation are considered and each of the different heat transfer phenomena are modeled in varying dimensions. The open-flame environment inside the furnace produces gases that participate in radiative heat transfer for which there are a number of different models. The P1 approximation to the method of spherical harmonics is used, both in three dimensions and a simplification to one dimensional radiation. The flow of gases inside the furnace is considered to be plug flow with a series of burners injecting hot gases along the length of the furnace. Conduction to the walls and work-piece occurs at much longer time scales than convection, i.e. the combustion gases are moving through the furnace much faster than the characteristic thermal response time of the walls and work-pieces (τgas ≪ τwall). This brings the modeler to the question of how to model transient effects at such disparate time scales. A model is posited that is a combination of quasi-steady radiative heat transfer, transient fluid evolution, and lumped transient conduction. This formulation takes advantage of the disparity in time scales to take large steps in time when solving the radiation equation while solving the energy equation at each time step for the internal gas control volumes. This model is then compared on the grounds of speed and accuracy to the more traditional explicit advancement of a consistent time step in both the gas energy balance and radiative transfer solution.
Evaluation of Wave Energy in the Pacific Ocean for Baja California State in Mexico
Authors: Tapia Olivas Juan Carlos , Delgado Rendón René , Hernández Martínez Emilio , Noh Pat Felipe , Villanueva Vega Eric Efrén , Castañón Bautista María Cristina 
Published: March 2016

According to the World Energy Council (WEC) the estimated energy of the wave power in the world is in the range of 8,000 to 80,000 TWh/year to depths of 100 meters or higher and actually the utilization of wave energy resource it is possible because it has been implemented in countries like Australia, Indonesia, Nigeria, United Kingdom, Norway, Portugal and Colombia evaluating different types of marine technologies that take the advantage of the kinetic energy in the ocean waves.
Mexico according to the National Institute of Statistics and Information (INEGI) has a land area of 1,972,550 km2 of which has a coastline of 11,150 km having potential for the use of their coasts. Baja California with a land area of 71,445 km2 (3.6% of the country) is located on a peninsula in northwest Mexico and has 720 km of coastline on the Pacific Ocean (6.4% nationally) with a range of depths of 25.6 m to 650 m at a distance of the coastline of 15 km, which makes it suitable to evaluate the use of wave energy at local sites.
With the completion of this work will contribute to the characterization of the sites that will present the best technical and economic conditions for its implementation, considering the physical characteristics of the site as well as connection points on the transmission lines operated by the Federal Electricity Commission (CFE).
For the preparation of this study was carried out in three stages: a) Site Selection, b) Evaluation of Wave Energy and c) Economic evaluation of sites using RETScreen.
Based on the characteristics of the coast of Baja California the results obtained are the following: 1) 18 sites were selected with a sea depth averaged of 50 m, the annual density power was 7.5 kW/m, this represents a potential of 210 MW considering an average length of 2 km in each site, 2) The economic evaluation of this type of project was for a period of 30 years in RETScreen, considers an annual inflation rate of 5% and obtains an investment cost of 9,538 US $/kW for this type of generation. We conclude that this source of energy will reduce dependence on fossil fuels and contribute to the generation of electricity in the state of Baja California diversifying the energetic matrix state by the use of clean and renewable sources, which represents an investment opportunity between the public and private sector.
Design and Optimization of the Restrictor of a Race Car
Authors: Kokkula Prithvi Raj , Bhojappa Shashank , Arslan Selin , Jawad Badih A. 
Published: March 2016

Formula SAE is a student competition organized by SAE International. The team of students design, manufacture and race a car. Restrictions are imposed by the Formula SAE rules committee to restrict the air flow into the intake manifold by putting a single restrictor of 20 mm. This rule limits the maximum engine power by reducing the mass flow rate flowing to the engine. The pull is greater at higher rpms and the pressure created inside the cylinder is low. As the diameter of the flow path is reduced, the cross sectional area for flow reduces. For cars running at low rpm when the engine requires less air, the reduction in area is compensated by accelerated flow of air through the restrictor. Since this is for racing purpose cars here are designed to run at very high rpms where the flow at the throat section reach sonic velocities. Due to these restrictions the teams are challenged to come up with improved restrictor designs that allow maximum pressure drop across the restrictor’s inlet and outlet. The design considered for optimizing a flow restrictor is a venturi type having 20 mm restriction between the inlet and the outlet complying with the rules set by Formula SAE committee.
The primary objective of this work is to optimize the flow restriction device that achieves maximum mass flow and minimum pull from the engine. This implies the pressure difference created due to the cylinder pressure and the atmospheric pressure at the inlet should be minimum. An optimum flow restrictor is designed by conducting analysis on various converging and diverging angles and coming up with an optimum value.
Venturi type is a tubular pipe with varying diameter along its length, through which the fluid flows. Law of governing fluid dynamics states that the “Velocity of the fluid increases as it passes through the constriction to satisfy the principle of continuity”. An equation can be derived from the combination of Bernoulli’s equation and Continuity equation for the pressure drop due to venturi effect. [1].
A Computational Fluid Dynamics (CFD) tool is used to calculate the minimum pressure drop across the restrictor by running a series of analysis on various converging and diverging angles and calculating the pressure drop. As a result, an optimum air flow restrictor is achieved that maximizes the mass flow rate and minimizes the engine pull.
An Effective Method for Fluid Dynamics Analysis of Inflow Control Devices
Authors: Filippov Andrey , Khoriakov Vitaly 
Published: March 2016

Horizontal wells are a widely applied architecture in modern field developments. However, because of the frictional pressure drop and reservoir permeability variations along the well, there is usually a non-uniform influx from the reservoir along the length and higher injection or production flow rates at the heel. Inflow control devices (ICDs) have been used for more than a decade to balance or equalize flow rates by creating additional pressure drop. To improve performance and longevity of the ICDs, their design must account for axial non-uniformity of pressure distribution and fluid flow details in the vicinity of the wellbore.
This paper discusses an effective approach to the problem and analytical solution of the pressure and flow field near the ICD section of the wellbore and prediction of the leveling of the non-uniform axial pressure distribution as a function of distance from the wellbore. The obtained analytical equations are validated through comparison with results of detailed numerical simulation using the finite difference method.
Particulate Matter: Fine and Ultrafine — How Emerging Data on Engineered Nanomaterials May Change How We Regulate Worker Exposures to Dust
Authors: Gernand Jeremy M. 
Published: March 2016

Currently in the United States, agencies responsible for regulations related to worker or public exposures to dust set rules based on a few general categories determined by gross particle size categories like PM10 (particles < 10 μm) and PM2.5 (particles < 2.5 μm) and the total mass of certain specific compounds (e.g., 3.5 mg/m3 of carbon black). Environmental health researchers however, have begun to focus on a new category of ultrafine particles (PM0.1; particles < 100 nm) as being more indicative of actual health risks in people. The emerging field of nanotoxicology meanwhile is providing new insights into how and why certain particles cause damage in the lungs by investigating the effects of exposure in animals to very well characterized engineered nanomaterials.
Based on this recent research the National Institute of Occupational Safety and Health (NIOSH) has issued new recommended exposure limits (RELs) for carbon nanotubes (CNTs) and titanium dioxide nanoparticles that are 2–3 orders of magnitude more stringent than RELs for larger particles of the same or similar substance. It remains unclear at present how stringent future regulations may be for engineered and inadvertently created nanoparticles or ultrafine dusts. Nor is it clear whether verification methods to demonstrate compliance with these rules could or should be devised to differentiate between engineered and inadvertently created nanoparticles.
This study presents a review of the history of dust regulation in the United States, how emerging data on the health risks of ultrafine particles and engineered nanoparticles is changing our understanding of the risks of inhaled dust, and how future rulemaking in regards to these and similar particulate materials may unfold.
This review shows the extent to which rules on dust have become more stringent over time specifically in the case of diesel emissions and silica exposure, and indicates that new rules on worker exposure to ultrafine dusts or engineered nanomaterials may be expected in the United States within 5–10 years based on past experience on the time delay in connecting research on new hazards to regulatory intervention. Current research suggests there will be several challenges to compliance with these rules depending on the structure of the final rule and the development of detection technologies. Although the research on ultrafine dust control technologies appears to indicate that once rulemaking begins there may be no serious feasibility limits to controlling these exposures. Based on ongoing exposure studies, those industries likely to be most affected by a new rule on ultrafine dusts not specific to engineered nanomaterials will include transportation, mining, paper and wood products, construction, and manufacturing.
Control for Robots With Braking Actuators in a Uniform Force Field
Authors: Framstad Erlend , Bedillion Mark D. 
Published: March 2016

This paper concerns the control strategy of a robot with controllable brakes placed in a uniform force field. Without loss of generality this force field is assumed to be gravity, and the robot to be an object resting on an inclined plane. The controller’s objective is then to use the brakes to lead the robot into a desired position and orientation.
The system’s dynamics were derived from Newton’s second law with a Coulomb friction model. The controller was derived from geometric properties and the energy equation. The controller was then tested using Matlab and Simulink on the dynamics that were derived. The results of the simulation shows high accuracy even with some disturbances, and uncalibrated parameters.
Numerical Investigation on the Effect of Aluminum Foam in a Latent Thermal Energy Storage
Authors: Buonomo Bernardo , Ercole Davide , Manca Oronzio , Celik Hasan , Mobedi Moghtada 
Published: March 2016

In this paper, a numerical investigation on Latent Heat Thermal Energy Storage System (LHTESS) based on a phase change material (PCM) is accomplished. The geometry of the system under investigation is a vertical shell and tube LHTES made with two concentric aluminum tubes. The internal surface of the hollow cylinder is assumed at a constant temperature above the melting temperature of the PCM to simulate the heat transfer from a hot fluid. The other external surfaces are assumed adiabatic. The phase change of the PCM is modeled with the enthalpy porosity theory while the metal foam is considered as a porous media that obeys to the Darcy-Forchheimer law. The momentum equations are modified by adding of suitable source term which it allows to model the solid phase of PCM and natural convection in the liquid phase of PCM. Both local thermal equilibrium (LTE) and local thermal non-equilibrium (LTNE) models are examined. Results as a function of time for the charging phase are carried out for different porosities and assigned pore per inch (PPI).
The results show that at high porosity the LTE and LTNE models have the same melting time while at low porosity the LTNE has a larger melting time. Moreover, the presence of metal foam improves significantly the heat transfer in the LHTES giving a very faster phase change process with respect to pure PCM, reducing the melting time more than one order of magnitude.
Shaped Magnetic Field in Resonance Technology and its Application to Transportation System
Authors: Cho Dong-Ho , Suh Nam Pyo , Yoon Uooyeol , Jung Guho 
Published: March 2016

KAIST has developed the Shaped Magnetic Field in Resonance (SMFIR) technology that transfers a large amount of energy to electric vehicles when they are running or stationary. The wireless charging SMFIR technology provides a solution to the commercialization barriers of electric vehicles such as the problems of batteries and charging infrastructure.
Using 20-kHz wireless power transfer system based on the SMFIR technology, our eco-friendly On Line Electric Vehicle (OLEV) bus was wirelessly powered by 100 kW through a power grid embedded under the road. On the other hand, using high-capacity, high-efficiency and low-cost 60kHz power supply and pickup systems based on the SMFIR technology, tram and high speed train were wirelessly powered by 180 kW and 1 MW through a power grid built in rail roads, respectively.
The commercial OLEV tram has been operated commercially from July 2011 in Seoul National Grand Park. Also, the OLEV shuttle bus has been operated for convenience of students and faculty members at KAIST campus since Oct. 2012. In addition, the world’s first intra-city OLEV bus with 100 KW pickup capacity has been operated commercially at Gumi city from March 2014. Then, airgap is about 20 cm and maximum power transfer efficiency is 85 %.
Long-Term Archiving of Exact 3D-CAD Geometry With JT
Authors: Trinkel T. , Anderl R. , Zocholl M. , Eichhorn H. 
Published: March 2016

The technology of Computer Aided Design (CAD) has been in use for 3D design for more than 30 years. Still today, the result of the 3D design process is usually a 2D engineering drawing. Thus, many downstream processes in the industry are dependent on engineering drawings. Nowadays, many companies are replacing their engineering drawings with 3D-CAD models and transforming their drawing-based processes into model-based processes. Consequently, these 3D-CAD models have to be archived and new methods to do so have to be implemented. The standardization of the Jupiter Tessellation (JT) file format specification as ISO 14306 could be an opportunity to use a single data format for both purposes: downstream processes and long-term archiving of exact 3D-CAD geometries.
This paper describes an approach for long-term archiving of exact 3D-CAD geometries. Initially the state of the art in long-term archiving methodology and archiving systems is analyzed. In order to enable an investigation from a technological point of view, the ISO JT data format is examined subsequently. The formal and technological requirements for a JT-based approach are then derived from these analyses. The next step is to introduce a conceptual process for long-term archiving of exact 3D-CAD geometries with the JT data. As a proof of concept, this approach is implemented prototypically. Through a comparison of the representation of exact 3D-CAD geometries in the JT and STEP data formats, the conditions for responsible long-term archiving using JT are defined.
As a conclusion, this paper provides an overview of the advantages and the associated risks of long-term archiving with the ISO JT data format for exact 3D-CAD geometries.
A Parametric Study of the Modeling of Orthogonal Machining Using the Smoothed Particle Hydrodynamics Method
Authors: Avachat Chinmay S. , Cherukuri Harish P. 
Published: March 2016

Modeling machining processes with conventional finite element methods (FEM) is challenging due to the severe deformations that occur during machining, complex frictional conditions that exist between the cutting tool and the workpiece, and the possibility of self contact due to chip curling. Recently, the Smoothed Particle Hydrodynamics (SPH) method has emerged as a potential alternative for modeling machining processes due to its ability to handle severe deformations while avoiding mass and energy losses encountered by traditional FEM. The method has been implemented in several commercial finite element packages such as ABAQUS and LS-DYNA for solving problems involving localized severe deformations.
Numerous control parameters are present in a typical SPH formulation. The purpose of this work is to evaluate the effect of the three most important parameters, namely, the smoothing length, particle density, and the type of SPH formulation. The effects of these parameters on the chip morphology and stress distribution in the context of orthogonal machining of AISI 1045 steel are investigated. The LS-DYNA finite element package along with Johnson-Cook material model is used for this purpose. Results from the parametric study are presented and compared with the previously reported results in the literature. In addition, the sensitivity of chip morphology and stresses to Johnson-Cook parameters for AISI 1045 steel is also investigated by considering five different sets of values reported in the literature for this steel.
Methane Steam Reforming and Metallic Membranes to Capture Carbon Dioxide in Gas Turbine Power Plants
Authors: Carapellucci Roberto , Favre Eric , Giordano Lorena , Roizard Denis 
Published: March 2016

Pre-combustion CO2 capture is regarded as a promising option to manage greenhouse gas emissions from power generation sector. In this regard, metallic membranes can provide a significant boost in power plants energy performances, due to their infinite hydrogen perm-selectivity and their ability to operate at high pressure and temperature. However, the properly integration of these devices still requires a deep investigation of power plant behavior, in order to detect the mutual interaction between system components, which may impose constraints on their operating conditions.
This paper aims to investigate a chemically recuperated gas turbine (CRGT) with pre-combustion CO2 recovery based on hydrogen separation through a metallic membrane. At first, the steam reforming and membrane separation processes are investigated, in order to assess their sensitivity to the variation of the main operating parameters. Then, the CRGT power plant with CO2 capture is analyzed, highlighting the effect of system components interaction on energy and environmental performances. In addition, the study accomplishes a preliminary investigation of the system capability to produce an excess of hydrogen to be used as an energy carrier.
Performance Analysis of a Silica Gel-Water Adsorption Cooler: Impact of Nanofluids on Cooler Performance and Size
Authors: Koronaki I. P. , Nitsas M. T. , Papoutsis E. G. , Papaefthimiou V. D. 
Published: March 2016

Thermally driven chillers also known as sorption heat pumps have drawn considerable attention in recent years. They can be divided into two main categories: absorption (liquid-vapor) and adsorption (solid-vapor) systems. Even though adsorption cycles have relatively lower coefficient of performance compared to absorption cycles, however they prevail in terms of heat source, electric consumption for moving parts, crystallization etc. In order to overcome the drawback of low COP and specific cooling capacity, nanofluids, i.e. mixtures of nanometer size particles well-dispersed in a base fluid, can be used as heat transfer fluids as recent experimental and theoretical research has proved that nanofluids can exhibit a significant increase on heat transfer.
In this study a two bed, single-stage adsorption chiller which utilizes the silica gel-water pair as adsorbent-refrigerant is simulated. The cooling capacity and the COP of the chiller are calculated for various cycle times. The usage of nanofluids as heat transfer fluids in the chiller evaporator and condenser and their effect on chiller performance and size is investigated. It is proved that the presence of nanofluids at different volume concentrations will enhance the cooling capacity and the COP of the adsorption chiller and therefore will lead to smaller, in terms of size, heat exchangers.