bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of the Discrete Ordinates Method to a Continuous Glass Furnace Model
Authors: Rodicio Sandra Coutín , Chapman Kirby S. 
Published: December 2021

Abstract
The radiative behavior of the glass as it flows through a continuous glass furnace is studied by applying the Discrete Ordinates Method (DOM). Through the application of the DOM the radiant intensity is calculated at each of the control volumes inside the glass tank domain. Consequently, the heat fluxes of the emitted and irradiated energy in the glass are obtained. The results are presented in terms of the radiant heat fluxes distribution and temperature profile of the glass. In addition, the variation of the glass surface emissivity is studied in order to provide further understanding of the impact of this property in the glass overall thermal behavior.
Modeling and Visualization of Plasma Spray Process for Depositing Functionally Graded Materials
Authors: Wan Y. P. , Gupta V. , Zhang H. , Varshney A. , Sampath S. , Prasad V. , Fincke J. R. 
Published: December 2021

Abstract
Recently, several models have been developed to simulate the plasma spraying process. The present paper extends our previous model (Wan et al., 1999a) to the plasma spray system of two-component materials with two different feed nozzles. It accounts for plasma-particle interaction, particle heating/melting/evaporation and solidification on the substrate. A special visualization algorithm has been developed to demonstrate the effects of various parameters on particle conditions while in flight, growth of functionally graded materials and distribution of the two components in the coating. Visualization of thermal processes is a challenging task if it has to be used for materials design and system development. It requires special schemes for data management in a multivariate system that includes at least velocity, temperature and species in four co-ordinates (space and time). Our effort is focused on developing a visualization scheme which goes far beyond the process animation and can be ultimately used for virtual prototyping of the processes, an area that needs special research efforts. Simulation and visualization have been performed for spraying of zirconia and NiCrAlY powders, with many combinations of powder injection features, e.g., number of nozzles, nozzle location and injection velocity. The fluctuation of the voltage is also simulated and animated to show its effect on both plasma gas and particle behavior. The optimized operating parameters are deduced from the distribution of these two materials in the coating layer. Issues related to visualization are also discussed.
Numerical Study of Thermal Modeling of Resistance Spot Welding Utilizing Coupled Thermal-Electrical-Mechanical Analysis
Authors: Xu Lijun , Khan Jamil A. , Chao Yuh-Jin , Broach Kirkland 
Published: December 2021

Abstract
This paper successfully proposes a novel model to predict nugget development during resistance spot welding (RSW) of binary Al-alloys. The model employs a coupled thermal-electrical-mechanical analysis, and also accounts for phase change and convective transport in weld pool. Faying surface contact area and its pressure distribution are simulated from coupled thermal-mechanical model using a finite element method. Temperature dependent thermal, electrical and mechanical properties are used. The proposed model can successfully calculate most of the RSW response in term of nugget diameter and thickness, the extent of heat affected zone, etc. The calculated nugget shape based on the thermal model agrees well with the experimental data. Convection effect due to the interactions between phases in the porous mushy zone and the buoyancy force arising from the temperature difference is determined to be not significant for the weld-nugget formation. The proposed model can be used to optimize RSW process parameters for industrial welding.
Resonance Based Force Measurement: Prelude to High-Resolution Anemometry for Liquid Metal Flows
Authors: Phan Son , Keanini Russell , Smith Stuart , Hocken Robert 
Published: December 2021

Abstract
This paper describes the first phase of a two-part project designed to develop a new anemometry method for use in high temperature liquid metal flows. The device will incorporate a dual-cantilever, PZT-driven touch sensor housed within a sealed, temperature resistant ceramic Pitot tube. Due to differing cantilever lengths, the device’s unloaded spectral response exhibits two distinct peaks, each corresponding to the cantilevers’ resonant frequencies. The principal of operation is based on the fact that pressure-induced forces on each cantilever produce resonant frequency shifts which can then be correlated with applied pressures. The first project phase has focused on development and testing of the dual cantilever touch-sensor and its supporting electronics. Two new concepts have been introduced in designing the touch sensor — use of a dual cantilever for simultaneous force measurement, and simultaneous detection of associated pressure-induced resonant frequency shifts. Here, we describe design of the Pitot tube, design and fabrication of the dual-cantilever sensor and electronics, and system modeling of the sensor. We also outline two pressure measurement schemes; in the first, pressure is correlated with resonant frequency shifts at constant phase while in the second, pressure is related to phase shifts (between forcing and response signals) at constant frequency. Device driving and sensing electronics have been fabricated as has the dual-cantilever touch sensor; preliminary experimental measurements of single and dual forces are presented.
Proposed Experimental Technique for Measuring Heat Transfer Coefficients Using a Pulsed Periodic Surface Heat Flux
Authors: Turnbull Wayne N. O. , Carscallen William E. 
Published: December 2021

Abstract
An analytical and numerical investigation has been carried out to ascertain the possibility of using a pulsed periodic surface heat flux to measure local surface heat transfer coefficients. The proposed technique is an extension of a previously proven experimental method. It is based upon the premise that the harmonics of a surface temperature response to an imposed periodic pulse will display phase shifting behavior that is a function of the thermophysical properties of the surface, the local heat transfer coefficient and the harmonic frequency. The phase behavior is not a function of the magnitude of the energy deposited by the pulse. Since phase behavior is being investigated there is no requirement to calibrate the surface temperature-sensing device. The numerical solution confirms the analytical results, which were obtained using a non-rigorous mathematical assumption. Results indicate that in order to maximize the sensitivity of the proposed experimental technique the pulse frequency should be kept low, the surface layer thin and the substrate thermal conductivity and diffusivity as low as possible.
A New Experimental Technique for Measuring Surface Heat Transfer Coefficients Using Uncalibrated Liquid Crystals
Authors: Turnbull Wayne N. O. , Oosthuizen Patrick H. 
Published: December 2021

Abstract
A new experimental technique has been developed that permits the determination of local surface heat transfer coefficients on surfaces without requirement for calibration of the temperature-sensing device. The technique uses the phase delay that develops between the surface temperature response and an imposed periodic surface heat flux. This phase delay is dependent upon the thermophysical properties of the model, the heat flux driving frequency and the local heat transfer coefficient. It is not a function of magnitude of the local heat flux. Since only phase differences are being measured there is no requirement to calibrate the temperature sensor, in this instance a thermochromic liquid crystal. Application of a periodic surface heat flux to a flat plate resulted in a surface colour response that was a function of time. This response was captured using a standard colour CCD camera and the phase delay angles were determined using Fourier analysis. Only the 8 bit G component of the captured RGB signal was required, there being no need to determine a Hue value. From these experimentally obtained phase delay angles it was possible to determine heat transfer coefficients that compared well with those predicted using a standard correlation.
Combined Pulsating and Capillary Heat Pipe Mechanism for Cooling of High Heat Flux Electronics
Authors: Zuo Z. Jon , North Mark T. , Ray Lee 
Published: December 2021

Abstract
This paper discusses an advanced heat pipe mechanism for cooling of high heat flux electronics. The mechanism combines the capillary effect of sintered metal powder wicks with a pulsating motion of the working fluid to maintain sufficient liquid supply to high heat flux regions. The pulsating motion is driven by thermal conditions in the heat pipe evaporator and condenser and can be sustained with proper internal flow channel design. A theoretical model was developed to describe the pulsating motion of the working fluid. Proof-of-concept copper/water heat pipes were tested to verify the heat flux capability of this advanced mechanism. The test results demonstrated over 220W/cm2 heat flux capability, a fourfold improvement over present state of the art heat pipe performance. Comparisons between the test results and the model predictions validated the theoretical model.
Experimental Study of the Transient Turbulence Generated by a Bubble Using PIV
Authors: Ortiz-Villafuerte Javier , Schmidl William D. , Hassan Yassin A. 
Published: December 2021

Abstract
The particle image velocimetry measurement technique was used to measure the whole-volume, three-dimensional, transient velocity field generated by a single air bubble rising in stagnant water in a small diameter pipe. The three-dimensional flow field was reconstructed using a stereoscopic technique. Conditional averages of the velocity fields for the situations when the bubble rises close to the center of the pipe, and close to the pipe wall were determined, and the turbulent motion generated in the continuous liquid phase for both situations was studied.
Artificial Neural Network Control of an Experimental Heat Exchanger Facility
Authors: Díaz Gerardo , Sen Mihir , Yang K. T. , McClain Rodney L. 
Published: December 2021

Abstract
The artificial neural networks technique is applied to control the dynamic behavior of a fin-tube single-row compact heat exchanger. The experimental setup consists of a variable-speed wind-tunnel facility built specifically for heat exchanger analysis. Two different control methodologies were studied. The first one corresponds to adaptive control in which the weights and biases of the artificial neural network that acts as a controller are modified depending on the error obtained between the desired outlet air temperature and its measured value. Experimental results show that the stability of the system varies depending on the different ways of performing the adaptation of the controller. The second control strategy tested corresponds to internal model control. We added a filter and an integral control structure to obtain an offset-free steady state prediction. The control methodology was extensively tested and the results compared to those of conventional PID control. The results were very favorable for the neural controller.
Results of Implementing an Introductory Course: Foundations of Thermal-Fluid Sciences
Authors: Ochterbeck J. M. , Gaddis J. L. 
Published: December 2021

Abstract
Pursuant to implementation of a new mechanical engineering curriculum at Clemson University, results of the new introductory course in thermal-fluid science are presented. This course is situated in the second semester of the sophomore year for mechanical engineering majors, and is a prerequisite for the subsequent courses in thermodynamics and fluid mechanics. In addition to introducing thermodynamic property analysis, the course develops conservation laws for mass, momentum, and energy and provides an emphasis in design. Discussion is presented of the motivation, placement in the overall curriculum, interaction with other curriculum elements, and the selection of textbooks.
A Partnership Between University’s Engineering Services Departments and Academic Departments for Energy Systems Education
Authors: Somerton Craig W. , Genik Laura J. , Schroeder Joseph , Thelen Wayne A. , Crouch Mike , Hudson Michael , Ellerhorst Robert , Gies Roy 
Published: December 2021

Abstract
Incorporation of plant tours into a laboratory course is discussed. The unique feature of these plant tours is that they are facilities on the university campus and utilize the expertise of the practicing engineers on campus to enhance the students educational experience. Examples of course materials used in these activities are provided.
Teaching Heat Transfer in a Studio Mode
Authors: Ribando Robert J. , Scott Timothy C. , O’Leary Gerald W. 
Published: December 2021

Abstract
Over the past four years we have transformed our undergraduate heat transfer course from a lecture format into what we call a “partial studio model.” Two lecture hours per week are supplemented with a two-hour “hands-on” session in a classroom equipped with a computer for each pair of students. Much of the studio work revolves around a suite of teaching modules that we have developed for use in our undergraduate and graduate heat-and-mass-transfer courses. Most modules include research-based numerical algorithms which solve the governing ordinary and partial-differential equations in real time. Several of the modules may be considered “virtual laboratories,” that is, they allow students to take data from the computer screen for post-processing — much as if they were working in a real, extremely well-equipped, laboratory. Others give the option of performing dozens of “what if” calculations rapidly, thus inviting use in the design process. Each module has been custom tailored for the particular topic; inputs and outputs are limited to only those essential to that problem. Thus, unlike most industry-grade computation fluid dynamics packages, there is virtually no “learning curve” associated with software operations. For a number of these modules we have developed an accompanying desktop experiment to enhance still further the hands-on nature of the studio.
NASA Ames Integrated Risk Assessment
Authors: Mendoza D. R. , Navarro R. J. , Flippen A. A. 
Published: December 2021

Abstract
NASA’s shift towards streamlined business practices depends on innovative management processes and tools. One such innovation, Risk Management (RM), has been levied as an Agency-wide requirement with corresponding policies which define the RM process. However, these policies are top level and do not necessarily ensure the institutionalization and transfer of the process’s best practices. Thus to implement the Agency’s philosophy while ensuring consistency and quality of risk assessments, the NASA Ames System Safety and Mission Assurance Office developed the Integrated Risk Assessment (IRA) process. IRA is the systematic use of both inductive and deductive assessment methods applied such that a risk is assessed for its potential harm to any resource and is tailored to the activity’s overall technical and programmatic constraints. Independently these methods are not unique; but their ensemble, which IRA represents, provides a powerful yet practical RM tool. This paper presents an overview and case study of the IRA process.
The Use of Performance Criteria in Developing Standard Methods for Land-Use Planning
Authors: Ale B. J. M. , Laheij G. M. H. , Post J. G. 
Published: December 2021

Abstract
The assessment and management of risk has been a matter of public and political interest for some decades.
The growing industry and the growing number of industrial products and services and the associated transport of goods have presented more and more partly unfamiliar hazards with which industry itself, but also the population and governments have had to cope. The Netherlands is one of the countries that struggled most explicitly with this problem. In the Netherlands risk is controlled by setting quantitative performance standards for the industry and for the spatial planners. These standards are expressed in limiting values for individual and societal risk.
The standards are used in the policy to reduce the number of people exposed to the effects of an accident. In principle, the societal risk for each new land-use plan should be re-calculated. Since this is proving increasingly cumbersome for planning agencies, several methods have been developed to determine the effects of new land-use plans on the societal risk. These methods give the uniform population density from a certain distance around the establishment at which the indicative limit for the societal risk is not exceeded. Correction factors are determined for non-uniform population distributions around the establishment, non-continuous residence times and alternative societal risk limits. Using these methods allows decision-making without the necessity of repeating quantified risk analyses for each alternative proposal.
Rheology and Bulk Flow Characteristics of a Thixotropic Fluid in Turbulent Pipe Flow
Authors: Pereira Américo S. , Pinho Fernando T. 
Published: December 2021

Abstract
In this work, aqueous suspensions of 1% and 1.5% by weight Laponite and a blend of 0.5%/ 0.07% Laponite/ CMC are investigated in terms of their rheology and their hydrodynamic behaviour in a pipe flow.
The viscometric viscosity was measured for all fluids, but due to the fluid thixotropy a flow-equilibrium procedure was adopted. All fluids were viscoplastic and the measurement of the yield stress was carried out by direct and indirect methods. The yield stress values were of 0.93, 2.13 and 3.4 Pa for the 1% Laponite, 0.5/0.07% Laponite/CMC blend and 1.5% Laponite suspensions, respectively. The oscillatory tests shows that the 1% Laponite suspension is inelastic but the other two suspensions exhibit some elasticity.
All solutions exhibited drag reduction with the difference between the total and shear-thinning drag reductions (DR – DRv) of the order of 10% to 20% for both pure laponite suspensions but increasing to 25 to 30% for the laponite-polymer blend. For the pure clay suspensions, and based also on evidence from the literature, it was speculated that DR – DRv, could be due to a strong decrease of the viscosity associated with a turbulence-induced destruction of the internal structure plus a second mechanism more akin to that found with drag reducing polymer solutions.
PRECO: A Novel Means of Determining the Pressure Coefficient of Viscosity Using a Modified Capillary Extrusion Rheometer
Authors: Carter Roy E. , Privett Grant J. , Allen Crispin R. G. , Brown Chris S. , Chakravorty Sekhar , Rides Martin 
Published: December 2021

Abstract
The viscosity of some polymeric fluids increases significantly when measured at pressures above atmospheric pressure. If this phenomenon is not taken into account for example when using CAD programmes to design injection moulding tools, then consequences such as short mouldings and inferior mechanical properties may be obtained, resulting in a high scrap rate and the need for expensive tool modifications.
A simple new method of measuring the pressure coefficient of viscosity using a tandem-die technique with a modified capillary extrusion rheometer is described.
Quasi-Static Capillary Impregnation of a Porous Fiber Bed
Authors: He J. , Altan M. C. 
Published: December 2021

Abstract
The impregnation of a fiber bed by capillary forces in a gravity field is analyzed. Fiber bed is modeled as infinitely long, parallel cylinders arranged in a hexagonal pattern. Quasi-static creeping flow equation is used to obtain the fluid front location and shape during impregnation of the fiber bed. The fluid front motion during impregnation are presented for different Bond numbers, contact angles and fiber volume fractions. It is found that impregnation velocity is significantly affected by contact angle and fiber volume fraction at the initial stages of impregnation. The influence of the Bond number becomes more significant when the fluid front approaches its final position where gravity balances capillary forces. The permeability of the fiber bed is also obtained from the time-dependent motion of the fluid front. The permeability predictions agree with the published experimental result and with those obtained by using lubrication theory.
Dilute Polymers and Coherent Structures in Wall Turbulence
Authors: De Angelis Elisabetta , Casciola Carlo M. , Piva Renzo 
Published: December 2021

Abstract
Both numerical and experimental data confirm that the introduction of dilute polymers in a turbulent flow changes some mean characteristics of the flow: the wall drag can decrease up to 40% while the average spacing among streaks can even double. Actually a link exists between streaks spacing and mean velocity gradient at the wall.
In such viscoelastic flows the wall turbulence regeneration is still influenced by the mean shear and by the interaction of the coherent structures even if they appear more ordered and larger with respect to Newtonian flows. These phenomena, which have been repeatedly observed since the findings of Toms, would require a better understanding of the mechanisms that locally induce this behaviour. The analysis of data from direct numerical simulation with FENE-P model for the polymers, seems to suggest, as the main effect of the viscoelastic reaction, a stabilizing action on the low speed streaks and a related decrease in the population of the wall layer coherent structures. The decreased level of activity induces relevant changes in the scales of the turbulence and originates the observed drag reduction.
Forced Convection in Channels With Viscous Dissipation for the Simplified Phan-Thien–Tanner Fluid
Authors: Pinho Fernando T. , Oliveira Paulo J. 
Published: December 2021

Abstract
The temperature distribution and the heat transfer coefficient for forced convection in laminar channel flow with viscous dissipation are derived for the simplified Phan-Thien–Tanner fluid with a linear stress coefficient. Fully-developed thermal and hydrodynamic conditions are assumed with a constant wall heat flux imposed on both walls. As a simplifying assumption the effect of temperature variations on the material parameters is neglected.
The results show that, in all circumstances, ie for wall heating and cooling and regardless of the magnitude of viscous dissipation, an increase of fluid elasticity and/or an increase of ε results in enhanced heat transfer. As a beneficial consequence the range of temperatures inside the duct is reduced. There is also a coupling effect of viscous dissipation and fluid elasticity: heat transfer enhancement by fluid elasticity is stronger in the presence of a more intense viscous dissipation. For positive wall heat fluxes, ie wall cooling, whenever the Brinkman number exceeds a threshold value, the viscous dissipation overcomes the wall cooling effect and the fluid heats up longitudinally. Fluid elasticity delays this critical Brinkman number to higher values.