bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Rapid Engine Prototyping Methodology: Linking Geometry, Flow Field, Combustion, Performance and Control
Authors: Ko Jang-Hyok , Guezennec Yann G. , Radwan Amr , Rizzoni Giorgio , Choi Woong-Chul 
Published: November 2021

Abstract
In this paper, we present an overview of a rapid engine prototyping methodology which can be an extremely valuable tool from preliminary engine design optimization to control system development. The methodology comprises several steps which can be used separately or in conjunction. Specifically, the approach consists of: i) linking engine geometry and valve events to in-cylinder flows; ii) linking in-cylinder flows to combustion characteristics; iii) linking combustion characteristics to crank-angle resolved engine simulation results; and iv) linking crank angle-resolved engine simulation results to a mean value dynamic engine/powertrain simulator to develop and optimize control strategies. One of the chief advantages of the proposed methodology is the ability of performing these tasks prior to having an engine prototype built and running on a dynamometer.
Velocity Control of Hydraulic Cylinders With Only Pressure Feedback
Authors: DeBoer Christopher C. , Yao Bin 
Published: November 2021

Abstract
The lack of position or velocity feedback is a very common problem particularly on construction equipment such as excavators and backhoes. The extra cost of adding position/velocity sensors is prohibitive as well as the high likelihood of sensor failure in such a harsh environment. These factors make the possibility of improving control performance with limited sensory feedback very attractive. This paper studies the velocity control of a single-rod double actuating hydraulic cylinder utilizing a programmable valve with only cylinder pressure feedback. The boom motion control of a scaled-down model of an industrial backhoe loader arm is used as a case study. The programmable valve used in this study is a unique combination of five proportional cartridge valves connected in such a way that the meter-in and meter-out flows can be independently controlled by four of the valves as well as a true cross port flow controlled by the fifth valve. The programmable valve decouples the control of the meter-in and meter-out flows providing tremendous control flexibility to control the cylinder motion while decreasing the pump energy required by utilizing the potential and kinetic energy of the load. This paper demonstrates the potential energy savings possible through the use of the programmable valve. The paper also proves that significant improvements in the velocity tracking performance of hydraulic cylinders can be attained with only pressure feedback.
Control Design for Ultimate Boundedness of Linear Switched Systems With Controlled and Uncontrolled Subsystems
Authors: Yedavalli Rama K. , Sparks Andrew 
Published: November 2021

Abstract
Motivated by the Satellite Formation Keeping Control Problem, this paper presents a theoretical framework for designing controllers for the ultimate boundedness of linear switched systems consisting of both controlled (and thus stable) and uncontrolled (unstable) subsystems. It is shown that if the dwell time in the controlled mode (i.e ‘on time’) and that of the uncontrolled mode (’off time’) are chosen judiciously, ultimate boundedness of the switched system is guaranteed. Towards this direction explicit formulae for the switching times between controlled and uncontrolled modes are provided as a function of the parameters of the ultimate boundedness region. Using Lyapunov theory, a control design procedure is presented that achieves a good trade off between the ratio of ‘off’ and ‘on’ times and the size of the ellipsoidal boundedness regions which are representative of the system performance. The proposed control design technique has useful applications in mechanical and aerospace systems. The importance of this theory and possible extensions of these concepts are discussed.
A Generalization of Poincaré’s Theorem to Periodic Hybrid and Impulsive Dynamical Systems
Authors: Chellaboina V. , Nersesov S. G. , Haddad W. M. 
Published: November 2021

Abstract
Poincaré’s method is well known for analyzing the stability of continuous-time periodic dynamical systems by studying the stability properties of a fixed point as an equilibrium point of a discrete-time system. In this paper we generalize Poincaré’s method to dynamical systems possessing left-continuous flows to address the stability of limit cycles and periodic orbits of left-continuous, hybrid, and impulsive dynamical systems. It is shown that resetting manifold (which gives rise to the state discontinuities) provides a natural hyperplane for defining a Poincaré return map. In the special case of impulsive dynamical systems, we show the Poincaré map replaces an nth-order impulsive dynamical system by an (n − 1)th-order discrete-time system for analyzing the stability of periodic orbits.
Multibody Dynamic Analysis of a 6-DOF Parallel Robot
Authors: Almonacid Miguel , Agrawal Sunil K. , Aracil Rafael , Saltarén Roque J. 
Published: November 2021

Abstract
This paper presents the dynamic analysis of a six-degree of freedom (dof) parallel robot based on multibody dynamics. The robot is also known as Stewart-Gough platform. The inverse and forward dynamic analysis is presented based on the Newton-Euler formulation with the imposition of the constraints through Lagrange multipliers and the application of the principle of virtual work. The singularity problem within the workspace is also focused and 3D surfaces where the robot reach singular configurations are shown. Finally, simulations for the inverse and forward dynamic of the robot have been carried out showing the computational cost.
The Motion of a Compliantly Suspended Rigid Body Constrained by a Frictional Surface
Authors: Huang Shuguang , Schimmels Joseph M. 
Published: November 2021

Abstract
In this paper, the quasistatic motion of an elastically suspended, unilaterally constrained rigid body is studied. The motion of the rigid body is determined, in part, by the position controlled motion of its support base and the behavior of the elastic suspension that couples the part to the support. The motion is also determined, in part, by contact with a frictional surface that both couples the rigid body to unilateral constraint surfaces and generates a friction force. The unknown friction force, however, is determined in part by the unknown direction of the rigid body motion. We derive a solvable set of equations that simultaneously determines both the friction force and the resulting rigid body motion. This set of equations requires that the friction and motion at the point of contact are oppositely directed. Solution involves the use of rigid body kinematics, the Coulomb friction coefficient, the commanded motion of the support, and the spatial elastic behavior of the coupling.
An Approach for the Design of Walking Humanoid Robots Having Different Leg Mechanisms and Using Dynamic Gaits
Authors: Bruneau Olivier , Ben Ouezdou Fethi , Fontaine Jean-Guy 
Published: November 2021

Abstract
This article describes a method to design humanoid robots and to generate their dynamic gaits. Firstly, the global design process which defines structures able to carry out dynamic locomotion tasks is explained. Secondly, a set of leg mechanisms are described to generate these tasks. The third section describes a method to produce intrinsic smooth motions for fest walking gaits of bipedal robots having different leg mechanisms. Finally, some simulation results are given.
Position Control of an Underactuated Planar 2R Manipulator
Authors: Rosas-Flores José A. , Alvarez-Gallegos Jaime , Castro-Linares Rafael 
Published: November 2021

Abstract
In this paper the problem of regulation of an underactuated planar 2R manipulator is solved by tracking appropriate planned trajectories. A class of parametric trajectories is propossed to reach a desired configuration. The parameters of the trajectories are found by using an optimization algorithm. Besides, a feedback control is proposed to regulate the manipulator under error modeling and small desviations on the initial conditions. By using simulations, it is illustrated that if the coordinates of the underactuated system track the planned trajectories then the system reaches the desired configuration.
From Human Arms to a New Generation of Manipulators: Control and Design Principles
Authors: Koeppe Ralf , Hirzinger Gerd 
Published: November 2021

Abstract
With the knowledge of the biological design of the human arm, we lay out the mechatronic design of a new generation of advanced light-weight robot manipulators with human-like dynamic characteristics. To achieve this property, the manipulator does not have to revert to a human-like, bionic design. A serial link manipulator, control technology, and sensorized joint actuators can generate a kinesthesis enabling high fidelity interaction of the robot with its environment. The design and control of the DLR light-weight robot is based on these principles. Based on generic properties governing the dynamic behavior of any arm, we discuss the difference between the human and the advanced robot arm. The mechatronic design of the advanced robot has to make use of these properties in a very different way than its biological counterpart to achieve a similar dynamic behavior.
Miniature Vapor Compression Refrigeration Systems for Active Cooling of High Performance Computers
Authors: Heydari Ali , Russell Kathy 
Published: November 2021

Abstract
A small refrigeration system for cooling of computer system components is evaluated. A thermodynamic model describing the performance of the cycle along with a computer simulation program is developed to evaluate its performance. The refrigeration system makes use of a miniature reciprocating vapor compression compressor. Due to space limitations in some high performance computer servers, a miniature refrigeration system composed of a compressor, capillary tube, a compact condenser, and a cold-plate evaporator heat exchanger are used. Mathematical multi-zone formulation for modeling thermal-hydraulic performance of heat exchanger for the condenser and evaporator are presented. The throttling device is a capillary tube and there is presented a mathematical formulation for predicting refrigerant mass flow rate through the throttling device. A physically based efficiency formulation for simulating the performance of the miniature compressor is used. An efficient iterative numerical scheme with allowance for utilization of various refrigerants is developed to solve the governing system of equations. Using the simulation program, the effects of parameters such as the choice of working refrigerant, evaporating and condensing temperatures on system components and overall efficiency of system are studied. In addition, a RAS (reliability, availability and serviceability) discussion of the proposed CPU-cooling refrigeration solution is presented. The results of analysis show that the new technology not only overcomes many shortcomings of the traditional fan-cooled systems, but also has the capacity of increasing the cooling system’s coefficient of performance.
Computational and Experimental Study of Thermo-Mechanics in a New Design of a Transceiver for High-Speed Telecommunications
Authors: Pryputniewicz Ryszard J. , Weller Steven A. , Shaw Sam R. , Herb William L. 
Published: November 2021

Abstract
High-speed telecommunications require ever increasing data rates, pushing the limits of existing hardware and driving the development of new data handling hardware. This paper addresses thermo-mechanical issues in a new Input/Output (I/O) device for high-speed telecommunications. This device is a surface mount-compatible fiber optic transceiver developed as the Small Form-Factor Pluggable (SFP) System. The development of the SFP System is supported by virtually every leading fiber optic transceiver manufacturer in the industry in accordance with the Multi Source Agreement (MSA). We describe the new MSA-compliant SFP System, develop a FEM model to simulate its thermal behavior under a variety of operating conditions, and present results of the simulation which are validated by selected experimental measurements.
Flow Characteristics of a Powder Lubricant in a Slider Bearing
Authors: Pappur Manjunath , Khonsari M. M. 
Published: November 2021

Abstract
This paper deals with a systematic development of theory of powder lubrication with the appropriate formalism based on the fundamentals of fluid mechanics. The theory is capable of predicting flow velocity, fluctuation (pseudo-temperature), powder volume fraction, and slip velocity at the boundaries. An extensive set of parametric simulations covering particle size, surface roughness, volumetric flow, load and speed are performed to gain insight into the performance of a powder lubricated thrust bearing. The results of simulations are compared to the published experimental results. Good agreement between the theory and experiment attests to the capability of the model and its potential for design of powder lubricated bearings.
Optimizing the Performance of a Fuel Induced Flue Gas Recirculation (FIR) System for Low Nox Boiler Burner Applications
Authors: Lorra Michael A. , Bussman Wes , Smith Joseph , Webster Tim 
Published: November 2021

Abstract
New burner design technologies are using the momentum of fuel gas injection to entrain flue gas for the purpose of diluting the combustible mixture in order to reduce NOX emissions. Using an eductor, these designs entrain flue gas from above the convection section of a furnace stack and mix with the fuel downstream of the eductor. This diluted fluegas/fuel mixture results in lower local adiabatic flame temperatures providing a reduction in NOX emissions. Test results show that NOX reduction performance is strongly dependent on the mass ratio of flue-gas to fuel. An entrainment mass ratio of flue-gas/fuel typically ranges between 2 to 3 pound flue-gas per pound fuel, leading to a NOX reduction of approximately 50 to 70 % for boiler burner applications. The flue gas entrainment performance is effected by pressure drop through the upstream and downstream FIR piping system. This paper describes optimization of an existing FIR system not meeting initial design performance. To improve the entrainment ratio several tools were used to re-design and optimize the FIR system. These tools included Computational Fluid Dynamics (CFD), semi-empirical modeling and cold flow test results. A detailed description and discussion of the results are presented.
NOx Emissions in a Steel Reheat Furnace Firing By-Product Fuels
Authors: Adams Bradley R. , Wang Dave H. 
Published: November 2021

Abstract
A DOE-funded program was used to understand the mechanisms that control the formation of NOx during the combustion of steelmaking by-product fuels and to investigate possible low-cost control options to minimize the NOx emissions. This paper discusses the CFD modeling results of NOx emissions in a reheat furnace. The reheat furnace has a total of 20 burners distributed over three firing zones. The furnace is fired at a rate of 250 × 106 Btu/hr and an overall stoichiometric ratio of 1.06 (fuel lean). Fuels with heating values of approximate 500 Btu/SCF were examined, including coke oven gas (COG), blast furnace gas (BFG) and a blend of COG, BFG, natural gas (NG) and nitrogen. A good range of process variables was modeled to examine effects of fuel type, air preheat, stoichiometric ratio, firing rate and burner stoichiometry distribution on NOx emissions.
Modeling results indicated that NOx formation in the reheat furnace is dominated by thermal NO, with some variation depending on the fuel fired. Temperature profiles showed an effective separation of the furnace interior into top and bottom zones as a result of the steel slab barrier. Higher temperatures characterized the bottom zone and elevated NOx levels as a result of the confined space and enhanced fuel air mixing provided by the slab supports. Results also showed that reburning of NOx plays a significant role in final NOx emissions with 30–40% of NOx formed being reduced by reburning in most cases. Modeling identified that operating the side burners in each burner zone slightly substoichiometric (while maintaining the overall furnace stoichiometry at 1.06) provided significant NOx reduction via reburning. NOx reductions of 23% and 30% were predicted when firing with COG and COG-NG-Air fuels, respectively. Overall furnace exit temperatures and heat flux profiles were not significantly affected by the biased firing.
Physical Scaling of Fire Suppression by Water Mist
Authors: Su G. , Quintiere J. G. , Schultz N. 
Published: November 2021

Abstract
The objective of the project is to develop water mist extinguishments design by scaling. The report describes the requirement and criteria of scaling fire, scale model, and the results of suppression for a developing water mist system design. The Maritime Safety Committee Draft Circular, MSC 914 is used as a basis test to evaluate a water mist design. A series of three full-scale tests related to MSC 914 were performed: fire only, fire with steel trailers, and fire with steel trailers and combustible commodities. A simulation was accordingly studied. Then, a scaled water mist design was tested in the scale model to find the characteristics needed for suppression in terms of pressure, water flow rate, droplet size, and the spray momentum. Based on these characteristics, a candidate nozzle will be selected for the full-scale MSC 914 test. The results so far show that the water mist system can effectively suppress the fire in scaled MSC 914 model. The full-scale MSC 914 is scheduled for September 2001. Therefore, the final answer is still pending until then. Scaling results are confirmed for temperatures, heat flux and flow for the MSC 914 fire without water add in.
A Comparison of Diffusion Flame Stability in One and Two Spatial Dimensions Near Cold, Inert Surfaces
Authors: Vance Robert , Wichman Indrek S. 
Published: November 2021

Abstract
A linear stability analysis is performed on two simplified models representing a one-dimensional flame between oxidizer and fuel reservoirs and a two-dimensional “edge-flame” between the same reservoirs but above a cold, inert wall. Comparison of the eigenvalue spectra for both models is performed to discern the validity of extending the results from the one-dimensional problem to the two-dimensional problem. Of primary interest is the influence on flame stability of thermal-diffusive imbalances, i.e. non-unity Lewis numbers. Flame oscillations are observed when Le &gt; 1, and cellular flames are witnessed when Le &lt; 1. It is found that when Le &gt; 1 the characteristics of flame behavior are consistent between the two models. Furthermore, when Le &lt; 1, the models are found to be in good agreement with respect to the magnitude of the critical wave numbers. Results from the coarse mesh analysis of the two-dimensional system are presented and compared to the one-dimensional eigenvalue spectra. Additionally, an examination of low reactant convection is undertaken. It is concluded that for low flow rates the behavior in one and two dimensions are similar qualitatively and quantitatively.
Large-Scale Laboratory Fire Whirls and Their Numerical Simulations
Authors: Satoh Kohyu , Naian Liu , Shinohara Masahiko , Yang K. T. 
Published: November 2021

Abstract
Fire whirls have been observed in large-scale forest and city fires, which are likely accompanied by strong winds and heavy damages such as loss of lives and physical properties. Despite the general interest in the research of fire whirls, their detailed mechanisms and physical effects still remain largely unknown. One reason is that such real fire whirls are of large size and their direct studies are obviously not feasible. On the other hand, CFD-based fire field models, despite their inherent deficiencies, do provide a rational means to scale the fire sizes. It is desirable, or even necessary, to study larger-scale fire whirls with higher whirling flames in the laboratory, along with their numerical simulations. If success in the numerical simulations for the larger fire whirls can again be demonstrated, we will then approach more closely to have a quantitative tool in the use of the fire field model to simulate and study the truly large real-life fire whirls. The purpose of the present study is to attempt to create a stable six-meter class whirling flame in the laboratory, and then compare the measured data with what can be simulated with a fire field model.
A Perspective on Combustion-Driven Flows With Circulation
Authors: Battaglia Francine , Rehm Ronald G. , Baum Howard R. , Hassan Mohamed I. , Saito Kozo 
Published: November 2021

Abstract
Perhaps the most dramatic example of surprising behavior when circulation is imposed on a combustion-driven flow is the fire whirl, where the burning gases form a tall slender column. Relatively few studies have addressed the influence of circulation on the development of combustion-driven flows. Three dimensionless parameters characterize this interplay: the Froude number, the swirl number and the Reynolds number. It is surprising that for most studies, even with plausible assumptions concerning the experiments, not enough information is given to determine the values of these parameters. We will experimentally reconstruct these studies in an effort to characterize parametrically these interactions. Both buoyancy-driven and momentum-driven combustion processes will be investigated to determine the influence of circulation. Theoretical studies will occur in conjunction to provide the most complete parametric investigation.
A Mixture Fraction Combustion Model for Large Scale Fire Modeling
Authors: McGrattan Kevin , Floyd Jason , Hostikka Simo 
Published: November 2021

Abstract
A numerical fire model, Fire Dynamics Simulator (FDS), is being developed at NIST to study fire behavior and to evaluate the performance of fire protection systems in buildings. To date, about half of the applications of the model have been for design of smoke handling systems and sprinkler/detector activation studies. The other half consists of residential and industrial fire reconstructions. Improvements are being made to address the second set of applications, most importantly a mixture fraction combustion model and a finite volume radiation transport algorithm using either a gray gas or a wide band assumption. The methods will be discussed and a sample calculation presented.
Transient Measurements of Gas Species Concentrations and Soot Properties in Pool Fires
Authors: Murphy Jeffrey J. , Shaddix Christopher R. 
Published: November 2021

Abstract
Researchers at Sandia National Laboratories have been investigating large-scale pool fires, both experimentally and numerically, for several years, because of the risk that these fires pose to critical engineered systems during transport accident scenarios [1]. In addition, Sandia recently implemented an insulated, water-cooled fiber optic probe that used a combined HeNe-laser-absorption, 2-color emission technique to determine soot volume fraction distributions and soot temperatures over a 2-cm sampling distance within 5-m diameter JP-8 pool fires [2].