bluuebunny/crossref_metadata_2025_split huggingface dataset:
Developing Real-World, Hands-On, Low Cost, Multi-Disciplinary Experiences for Undergradute Students
Authors: Nasr Karim J. , Jordan Colin 
Published: January 2022

Abstract
This paper presents the use of a vehicle and its components to convey various principles in the area of thermal sciences. The experiences were designed to provide students with hands-on exposure to real systems, develop innovative laboratory experiments and incorporate multi-disciplinary projects in thermal sciences. A total of about ten experiments were derived from the donated vehicle, they included a coast down test, a fuel system test stand, a HVAC unit, and a mechanism experiment, just to name a few. Students explored with the components of the vehicle to develop several laboratory experiments, reverse engineering, and set-up experimental apparatuses for research. This paper describes one laboratory setup, the HVAC system, presents its classroom implementation and related educational objectives, and documents student feedback and faculty reflections on the experiences.
Thermocapillary-Coriolis Instabilities in Liquid Bridges
Authors: Cunff Cédric Le , Zebib Abdelfattah 
Published: January 2022

Abstract
Coriolis effects on thermocapillary instabilities in a liquid bridge of infinite length are investigated. The flow is driven by an imposed temperature gradient along the z-direction in a (r, θ, z) rotating frame of reference. When the rotation vector is parallel to the z-axis the base return flow with no rotation is not modified. In this case, rotation is stabilizing with traveling waves preferred. If the rotation is orthogonal to the z-axis, the base flow is modified and is no longer one-dimensional. Asymptotic methods valid for small rotation are used to calculate the base flow which may become multicellular, both in the radial and azimuthal directions, depending on the Prandtl, Marangoni, and Diot numbers. Linear stability analysis of the new base flow indicates that this type of rotation can be destabilizing while traveling azimuthal waves continue to be the prefered form of convection. Finally, the effect of rotation is studied in a finite length cylinder by direct numerical simulation.
A Numerical Study of Directional Solidification and Melting in Microgravity
Authors: Chen P. Y. P. , Timchenko V. , Leonardi E. , de Vahl Davis G. , de Groh H. C. 
Published: January 2022

Abstract
A computational model is presented for the study of the solidification and melting of a pure substance and of a binary alloy. The enthalpy method has been used, and incorporated into a commercial CFD code. Three examples of the use of the model are described: the three-dimensional solidification of a pure substance (succinonitrile), the results of which are compared with experiment; an example of the solidification of a bismuth-tin alloy; and a simulation of a solidification and melting experiment done in space known as the MEPHISTO program.
Numerical Analysis of Unsteady Marangoni Flow in a Square Cavity Under Reduced Gravity
Authors: Torii Shuichi , Yano Toshiaki , Tsuchino Fumihiro 
Published: January 2022

Abstract
A numerical study is performed on unsteady natural convection heat transfer and fluid flow in a cavity under reduced gravity. Consideration is given to the influences of Marangoni and buoyancy convections on the thermal and velocity fields in a two-dimensional square cell. Here, it consists of two opposing vertical side walls held at constant but different temperature with the horizontal lower wall insulated and the upper face treated as non-deformable adiabatic free surface. The governing equations are discretized by means of a finite-difference technique and numerically solved. If only the buoyancy convection is taken into account, the fluid temperature gradient in the cavity under the reduced gravity is substantially decreased near the hot and cold vertical walls and the dominant heat transfer mechanism switches from convection into conduction, as time progresses. In other words, the heat transfer performance is substantially attenuated due to the absence of buoyancy. On the contrary, the corresponding flow pattern is similar to that under normal gravity condition, resulting in a slight deterioration of the heat transfer performance, if both Marangoni and buoyancy convections interact. Therefore, this is found to be the dominance of Marangoni flow over natural convection in the system considered.
Design and Development of a Sidewall Vent System for Airflow Distribution and Decompression Protection in Commercial Aircraft
Authors: Petersen Brian J. , Buzza Timothy G. , Shim Hyo S. 
Published: January 2022

Abstract
In existing commercial aircraft the air conditioning system delivers air to the cabin for temperature control and cabin pressurization. The conditioned air introduced into the passenger cabin flows down to the utility tunnels under the floor through the sidewall vents and to an outflow valve or valves located on the fuselage of the aircraft and eventually to the ambient pressure. The function of the vent system is to provide cabin air distribution flow control and also to provide decompression protection. In the event of a fuselage decompression the pressure differential between the upper and lower compartments must not exceed the structural limits of the cabin floor. The cabin vent system is designed to limit this pressure differential by increasing the flow area between the upper and lower compartments in the event of a rapid decompression. The differential pressure loads on the floors were analyzed using a rapid decompression computer code.
Lab testing was performed to verify the differential pressure at which the mylar panel ruptures. This testing used a vacuum chamber test setup. The sidewall vent system was exposed to ambient air pressure on one side and quickly exposed to the vacuum system pressure on the other side. These test results were used in the rapid decompression analysis. There are multiple sidewall vents along the length of an aircraft cabin. Therefore aircraft testing was utilized to verify airflow distribution in the aircraft.
An Experimental Investigation of Steam Injection in Fractured Porous Media
Authors: McCreery Glenn. E. , Martineau Richard C. 
Published: January 2022

Abstract
Experiments were conducted which model steam condensation front propagation during the Steam Enhanced Extraction (SEE) process of removing liquid contaminants in fractured porous media*. The process is being considered for implementation for removal of contaminants in the basalt flows which lie above the Snake River aquifer at the Idaho National Engineering and Environmental Laboratory (INEEL). The SEE process consists of steam injection into porous media which is unsaturated, or partially or completely saturated with water and contains (typically) organic contaminants. The steam condenses and sweeps the contaminant along with the condensate toward a low pressure region established by a vacuum (and water) pump. The experiments described are the first in a series to compare and extend results obtained by others for homogeneous porous media, and layers of homogeneous porous media to fractured porous media. Experiment results and thermal analysis are presented.
Modeling Regional Climate Impacts of a Proposed Hydroelectric Project
Authors: Sailor David J. , Rosen Jesse N. 
Published: January 2022

Abstract
This paper is a preliminary analysis of the potential for atmospheric thermal pollution from a man-made reservoir. The specific site for the study is a proposed hydroelectric project on the Sogamoso River in Colombia, S.A. The region is agricultural with the two staple crops being coffee and cocoa. These two crops are sensitive to both high temperatures and more dramatically to high humidity levels. Farmers from the region are concerned that the construction of the reservoir will negatively impact crop yield. We have used a numerical atmospheric model to simulate weather from the region both without and with the proposed reservoir. Simulations show the magnitude of the impact is too small to be of consequence to crop yield. With these results we draw conclusions about the potential impact of the reservoir on climate. This paper provides a brief introduction to the theory behind the climatic consequences of a large lake. Results are then discussed for two time periods, one during the rainy growing season and one during the dry season. One of the biggest uncertainties in the model boundary conditions arises from the specification of the lake temperature, so the sensitivity of the model to lake temperature is analyzed for one of the study dates. Finally it is shown how a small set of weather simulations are used to draw climatic conclusions.
Neck Down and Thermally Induced Defects in High Speed Optical Fiber Drawing
Authors: Yin Z. , Jaluria Y. 
Published: January 2022

Abstract
The drawing speeds employed in the manufacturing of optical fibers have been rising in recent years due to the growing worldwide demand. However, increasing speeds have placed stringent demands on the manufacturing process, mainly because of large temperature gradients that can generate thermally induced defects and undesirable variations in fiber characteristics. Heat transfer and glass flow that arise in drawing fibers of diameters 100–125 microns from cylindrical silica preforms of diameters 5–10 cm play a critical role in the success of the process and in the maintenance of fiber quality. This paper presents an analytical and numerical study of the optical fiber drawing process for relatively large diameter preforms and draw speeds as high as 20 m/s. The free surface which defines the neck-down profile is determined by a force balance and an iterative numerical scheme is employed to obtain the profile under steady conditions. The transport in the glass is calculated to obtain the temperature, velocity and defect distributions. The problem is complicated because of combined radiation, convection and conduction mechanisms that govern this important manufacturing process. A zone radiation model is used for calculating radiative transport within the glass. Because of the large reduction in the diameter of the preform/fiber, the velocity level increases dramatically and the geometry becomes complicated. A coordinate transformation is used to convert the domain to a cylindrical one. Wherever possible, the numerical results are compared with experimental and numerical results in the literature for smaller draw speeds for validation. The effects of high draw speeds and of other physical variables on defects generated in the fiber, on the neck-down profile, and on the relevant transport processes are determined.
Continuously Moving Finite Thickness Susceptor in CVD Processing
Authors: Chiu Wilson K. S. , Jaluria Yogesh 
Published: January 2022

Abstract
Chemical Vapor Deposition (CVD) of thin films onto a moving surface is presented in this study. Conjugate heat and mass transfer processes with surface reactions and conduction effects in the susceptor are numerically investigated. The numerical model is validated for silicon deposition through comparisons with analytical results and experimental data. Results show that a moving susceptor with finite thickness can have a significant effect on deposition rates. Films produced by continuous CVD processing are shown to have a strong dependence on several operational parameters. Increasing susceptor speed and susceptor thickness results in lower deposition rates, thereby decreasing the final film thickness. Enhanced film deposition is obtained by the use of low thermal diffusivity material or by increasing the heating zone size. The governing parameters are correlated to include these effects under typical operating conditions. The results and correlations may be used as guidelines for future CVD reactor design.
Thermal and Carrier Transport in Laser Photo-Etching of n-GaAs Semiconductor Thin Films
Authors: Zhang X. , Wen J. 
Published: January 2022

Abstract
Coupled thermal and carrier transport (electron/hole generation, recombination, diffusion and drifting) in laser photo-etching of GaAs thin film is investigated. A new volumetric heating mechanism originated from SRH (Shockley-Read-Hall) non-radiative recombination and photon recycling is proposed and modeled based on recent experimental findings. Both volumetric SRH heating and Joule heating are found to be important in the carrier transport as well as the etching process. SRH heating and Joule heating are primarily confined within the space charge region which is about 20 nm from the GaAs surface. Surface temperature rises rapidly as the laser intensity exceeds 105 (W/m2). Below a laser intensity of 105 (W/m2), thermal effect is negligible. The etch rate is found to depend on the competition between photo-voltaic and photo-thermal effects on surface potential. At high laser intensity, etch rate is increased by more than 100% due to the SRH and Joule heating.
Modeling Issues for Reactive Spray Atomization and Deposition Processes
Authors: Delplanque Jean-Pierre , Rangel Roger H. 
Published: January 2022

Abstract
The primary goal of the present work is to define a model to predict the characteristics of materials processed using reactive spray atomization and deposition. The materials considered are aluminum alloys while target dispersoids are primarily oxides. These may be obtained by the reaction of oxygen-containing atomization gas mixtures with molten alloy droplets. Droplet position and velocity histories are obtained from the numerical solution of the one-dimensional equation of motion. The energy equation inside the droplet is solved numerically using finite-differences to predict the spatially resolved temperature field. The solid/liquid interface progression rate is estimated using a power law while an oxidation rate expression based on the Mott-Cabrera theory is used for the oxide thickness. Such a model can then be used to determine the parameters controlling the volume fraction and the size distribution of the dispersoids for various systems.
A Multigrid Simulation of the Rapid Solidification of a Pendent Molten Ball
Authors: Sripada Srinivas S. , Cohen I. M. , Ayyaswamy P. S. 
Published: January 2022

Abstract
We consider the solidification of a molten ball pendent at the end of a metallic wire. The melting is caused by the heat from a weakly ionized plasma (dominated by charge-neutral collisions). The low current plasma discharge supplies energy to the wire whose tip subsequently melts. The melt so formed rolls up due to surface tension into a pendent spherical segment at the bottom of the wire. The electric discharge is then extinguished and the melt is allowed to rapidly solidify in the ambient atmosphere. We numerically simulate this solidification process by using a body-fitted adaptive grid scheme. An energy balance at the interface between the solid and molten phases is used to track the motion of the melt interface as the molten segment solidifies. The equivalent heat capacity method is used to account for the latent heat and the “mushy” layer. The set of governing equations is discretized using a finite-volume method, and a multigrid iterative solver is used to solve the system. We evaluate the transient temperature distribution in the layer. Such an evaluation has important applications both in microelectronic packaging and in plasma processing. Results from a simulation of the electronic flame off discharge process employed in micro-electronic packaging (wire bonding) are presented.
Analysis of Heat Transfer to a Spectrum of Particles in Plasma Spray Coating Process
Authors: Verma Alok , Jog Milind A. 
Published: January 2022

Abstract
In plasma spray coating process, ceramic/metallic particles are introduced in a flow of thermal plasma. The heat transfer from the plasma to the particles results in heating and melting of the particles. The molten particles then impinge on a substrate to be coated. The impacting particles spread on the substrate due to their high velocities forming a thin layer. Heat transfer from the particles to the substrate results in rapid solidification and formation of a thin protective coat on the substrate. The heat transfer to/from particles affects the quality of the coatings. It is therefore important to predict and control the particle heat transport. In this paper, we have considered a spectrum of particles moving in thermal plasma. The particle spectrum is represented by a regular array of identical particles. The particle longitudinal and lateral spacing is varied independently to study the effect of particle spacing on the flow and heat transport. The Reynolds number based on the particle diameter is in the intermediate regime (Re ∼ 20–100). The background gas, argon, is at atmospheric pressure and the flow is considered steady. The flow and transport is analyzed by a cylindrical-cell numerical model. An orthogonal adaptive grid is generated to body-fit the particle surface as well as the cylindrical outer boundary of the cell envelop. The grid near the surfaces of the particles is very fine and resembles spherical co-ordinates. The conservation equations for mass, momentum, and energy are solved in the plasma by a finite volume numerical method. The flow field and the temperature distribution are calculated in the plasma for various combinations of lateral and longitudinal particle spacings. The local variations of the viscous and pressure forces acting on the particle surface as well as the local Nusselt number variations are calculated. The overall Nusselt number and the drag force acting on each particle are determined. Results indicate that the flow and transport around a given particle is significantly influenced by the presence of the adjacent particles.
The heat transport and drag force results for a particle in a spray are substantially different from those available for an isolated particle at the same Reynolds number. An increase in the lateral spacing between particles results in a decrease in the Nusselt number as well as the drag coefficient. In contrast, increasing longitudinal particle spacing leads to an increase in both the Nusselt number and the drag coefficient. At lateral spacings greater than about four diameters, the effect of side particles becomes negligible. However, the influence of upstream particles remains significant even at longitudinal particle spacing of five diameters. Simple correlations for the overall Nusselt number and drag coefficient have been proposed to incorporate the effect of inter-particle interactions.
Multi-Spatial-Temporal Grids for Three Dimensional Transient Conduction Problem
Authors: Siu W. W. M. , Lee S. H.-K. 
Published: January 2022

Abstract
Computationally intensive problems are often encountered in numerical heat transfer studies. One of the major cause is the small time steps brought forth by the fine spatial grid required at critical regions. Consequently, computational efficiency becomes one of the key issue in such numerical studies. By and large, the existing methods for enhancing computational efficiency either are only applicable for iterative operations, or provide limited speed-up because the solutions at the certain regions within the domain are marching with an unnecessary small time step. This work presents the development of a new method which achieves a higher computational efficiency. This method is herein referred to as the Multi-Spatial-Temporal Grid (MSTG) method, and it provides a significant speed-up by simultaneously implementing grid reduction and multiple timesteps. This method has been tested to be effective in improving the computational efficiency of conduction problem in transient multi-dimensional orthogonal coordinates. Current benchmarking showed the solution obtained from this method to be within 0.04% of those obtained from a uniform grid. In addition, the speed-up of this scheme was found to be significantly higher than most existing methods.
Control of Convergence of a Computational Fluid Dynamics Algorithm Using Fuzzy Logic
Authors: Dragojlovic Zoran , Kaminski Deborah A. , Ryoo Juntaek 
Published: January 2022

Abstract
Relaxation factors in an iterative fluid flow solver are adjusted by fuzzy logic to achieve automatic convergence of the solution. Three benchmark problems are considered, including a lid-driven cavity, free convection in a square enclosure, and flow in a channel with a backward-facing step. The SIMPLER algorithm with simple substitution is used to solve the incompressible Newtonian conservation equations. The relaxation factors for u and v velocities and temperatures are adjusted on each iteration according to a specified rule set. The control logic allows the algorithm to restart automatically if divergence is imminent. Convergence was achieved in all cases and the CPU time required for convergence with fuzzy control is not far from optimum, compared to that required using conventional constant relaxation factors.
Numerical Bifurcation and Chaos in a One-Dimensional Nonlinear Combined Mode Problem and the Inverse Application
Authors: Lan Chao-Ho , Howell John R. 
Published: January 2022

Abstract
Radiative heat transfer coupled with the other modes is described by highly nonlinear integro-differential equations. Due to the existence and uniqueness of a real positive temperature distribution, numerical solutions should be obtainable. However, experience shows that the solutions usually present convergence difficulties unless we carefully vary parameters and iterate numerous times, depending on the numerical method chosen for solution. In nonlinear analysis, the main objective of bifurcation and chaos theory is to study how the solutions of equations vary as the parameters are varied. This work presents a computational study of bifurcation and chaotic behavior in numerical solutions of combined-mode problems and how that behavior changes with different values of the parameters. Then, maps of the limits of bifurcation and chaos are made, which show the region of convergence. These should be beneficial to the researchers who attempt to program combined mode problems. Finally, a 1-D inverse combined mode problem is investigated to demonstrate the efficiency of the map.
New Objective Approaches for Characterization of Interfacial Structures in Two-Phase Flow
Authors: Ishii M. , Mi Y. , Tsoukalas L. H. , Kim S. 
Published: January 2022

Abstract
Two objective approaches for characterizing the interfacial structures and identifying flow regimes in two-phase flow are presented. The first approach is based on the use of a multi-sensor probe technique to get detailed local information. Performance of a newly designed four-sensor conductivity probe was investigated in a vertical test section with 50.8 mm i.d. The experimental data is categorized into two groups in view of their interfacial structures. Local information on the void fraction, interfacial area concentration, Sauter mean diameter, interface velocity, etc., was obtained successfully. The experimental data demonstrate well the characteristics of the two groups of bubbles.
The second approach is based on the application of a non-intrusive impedance void-meter and neural networks. An advanced non-intrusive impedance void-meter provides input signals to neural networks which are used to identify vertical flow regimes. Both supervised and self-organizing neural network learning paradigms performed flow regime identification successfully. The methodology presented holds considerable promise for multiphase flow diagnostic and measurement applications.