bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detailed Heat Transfer Coefficient Distributions Under an Array of Impinging Jets With Coolant Extraction
Authors: Huang Yizhe , Ekkad Srinath V. , Han Je-Chin 
Published: July 2023

Abstract
Jet impingement cooling is a high performance technique for heat transfer enhancement. Local heat transfer distributions are presented for an array of jets impinging on a target plate with a series of coolant extraction holes. The flow enters the pressure channel, impinges on the target plate and exits toward the sides and through the coolant extraction holes. The impingement plate has four rows of 12 jet holes and the target plate has three rows of 11 coolant extraction holes. The jet holes and the coolant extraction holes have the same diameters and are staggered such that the air impinging from the jet hole does not exit directly through the extraction hole. The detailed heat transfer coefficient distributions are measured using a transient technique and liquid crystal coating. Results are presented for a range of jet Reynolds numbers between 4000 and 20000. The effect of crossflow is also studied by changing the exit opening of the impingement channel to provide three different spent air exit directions. Heat transfer results for the target plate with coolant extraction are compared with those without coolant extraction at the same flow conditions.
Heat Transfer From a Liquid Bath due to an Impinging Gas Jet: Effect of Liquid Prandtl Number
Authors: Qian F. , Farouk B. , Mutharasan R. , Macken N. 
Published: July 2023

Abstract
There have been extensive heat transfer studies of impinging gas jets on solid surfaces, but few investigations of gas jet/liquid bath interaction. Here we report on the effects of liquid Prandtl number on air-jet induced transport in a bath. Two different liquids having widely different Prandtl numbers (silicone oil and a molten metal alloy, Amalloy-203®) were used. Both numerical calculations and experiments were carried out to characterize the jet induced flow and heat transfer in the liquid. The mixing and thermal behavior of the heated bath were determined as functions of the air jet characteristics (inlet temperature, Reynolds number, diameter and nozzle distance from the bath surface) and bath properties (depth, diameter, and liquid Prandtl number).
Forced Convective Liquid Cooling of Arrays of Protruding Heated Elements Mounted in a Rectangular Duct
Authors: Gupta Anurag , Jaluria Yogesh 
Published: July 2023

Abstract
Experiments are performed to study single-phase forced convection water cooling of arrays of protruding heat sources. Each array has four rows, with three elements in each row. Two arrays are mounted, one at the top and the other at the bottom of a rectangular channel. The Reynolds number based on channel height is varied from 2500 to 9000. Flow visualization revealed that the flow was fully turbulent even at the smallest Reynolds number. Different channel heights, ranging from 3 to 4 times the height of the elements, different heat inputs to the modules and different streamwise spacing between the elements are employed. The spanwise spacing between the elements is kept constant. It is found that the Nusselt number is higher for smaller channel heights and streamwise spacing, at constant Reynolds number. Buoyancy effects are found to be negligible over the parametric ranges considered here. A small variation in the heat transfer coefficient is found in the spanwise direction. The observed trends are considered in terms of the underlying transport processes. The heat transfer data are also correlated in terms of algebraic equations. High correlation coefficients attest to the consistency of results. The data are compared with previous air and water cooling studies, wherever possible, and a good agreement is obtained.
Application of Isokinetic Sampling Technique in Stratified Multiphase Flows
Authors: Khor Siew H. , Mendes-Tatsis Maria-Alcina , Hewitt Geoffrey F. 
Published: July 2023

Abstract
This paper describes the development of an isokinetic sampling probe ultimately intended for application in three-phase gas-liquid-liquid stratified flows in horizontal pipes. The probe is designed with an aim to give information on local fluid flow rates and the fractions of the respective liquids (oil and water) within the flow. The paper also presents the validation of the developed isokinetic sampling probe against single phase flow measurements and preliminary tests with the probe in air-water and air-oil-water stratified flows in a horizontal pipe. The results obtained (believed to be the first application of such a probe in stratified flows) are encouraging and consistent with previous findings.
A Comparison of Correlations for Forced Convection Heat Transfer From a Submerged Melting Ice Sphere to Flowing Water
Authors: Aziz Syed Amer , Janna William S. , Jakubowski Gerald S. 
Published: July 2023

Abstract
The objective of this study is to develop an empirically based expression for forced convection heat transfer from a melting ice sphere to a flowing liquid. A series of experiments were conducted to measure the forced convection heat transfer rate from a submerged ice sphere to water. The range of Reynolds numbers, based on characteristic length of the sphere, was between 2 500 and 25 000. The characteristic length for the melting sphere was defined in terms of the initial and final conditions of the specimen. Results of this study correlate well with previous studies related to forced convection. The data of this study can be described with an equation for the Nusselt number in terms of Reynolds and Prandtl numbers.
Finite Element Analysis of a Dissimilar Mixed Mode Bimaterial Interfacial Fracture Specimen
Authors: Zhang Jinmiao , Lu Gui-Ying , Kenner Vernal H. , Soboyejo Wolé 
Published: July 2023

Abstract
A finite element model of a dissimilar mixed mode bimaterial interfacial was generated using the commercial FEMAP software and analyzed using ABAQUS. Finite element techniques were used to estimate the strain energy release rates of interfacial cracks in a copper/moulding compound system. The finite element results are shown to be in good agreement with theoretical predictions of the strain energy release rate obtained from an analytical linear elastic fracture mechanics model. The finite element techniques were also used to estimate the loading conditions that are required to avoid contact between the crack surfaces under monotonic loading.
Damage Initiation and Propagation in Metal Laminates
Authors: Riddle Robert A. , Lesuer Donald R. , Syn Chol K. 
Published: July 2023

Abstract
The metal laminates proposed here for use in aircraft structures consist of aluminum alloy interlayers between aluminum alloy based metal matrix composite (MMC) plates reinforced with silicon carbide particles. The properties of the laminates are to be tailored for applications in jet engine fan containment and in various wing and auxiliary support structures. One important mechanical property of the metal laminate is fracture toughness.
This composite metal structure is designed to have enhanced ductile fracture properties as a result of the plastic formability of the aluminum layers and increased strength and stiffness due to the layers of the metal matrix composite.
The enhanced fracture properties of the metal laminates are measured by fracture toughness specimens of several designs. Of particular interest is the optimum thickness of the ductile interlayer to optimize the fracture properties, but have the least effect on the strength and the stiffness. Specimen designs have been chosen which should allow measured properties of the specimen deformation and failure to be translated into predictions of component strength in actual aerospace applications.
One mode of crack growth which increases fracture toughness and damage resistance in applications of interest is extensive delamination between the ductile interlayer and the MMC plates.
The total area of delamination is increased by the tendency of metal laminates to have damage initiate at the lobes of contours of effective plastic strain which are significantly off-axis from the plane of Mode I or tensile mode opening crack growth. This off-axis damage increases the delaminated area and is a factor in forcing the crack to reinitiate at a new location in the next MMC plate.
Experimental evidence for this phenomena is presented, along with finite element calculations which quantify and explain enhanced fracture values. The progressive damage is modeled using tie-break slidelines with critical strains to failure chosen with the help of elastic-plastic fracture mechanics calculations.
Evaluation of Multi-Phase Heat Transfer and Droplet Evaporation in Petroleum Cracking Flows
Authors: Chang S. L. , Lottes S. A. , Zhou C. Q. , Petrick M. 
Published: July 2023

Abstract
A computer code ICRKFLO was used to simulate the multi-phase reacting flow of fluidized catalytic cracking (FCC) riser reactors. The simulation provided a fundamental understanding of the hydrodynamics and heat transfer processes in an FCC riser reactor, critical to the development of a new high performance unit. The code was able to make predictions that are in good agreement with available pilot-scale test data. Computational results indicate that the heat transfer and droplet evaporation processes have a significant impact on the performance of a pilot-scale FCC unit. The impact could become even greater on scale-up units.
Experimental Observations of Swirling Fires
Authors: Satoh Kohyu , Yang Kwang-Tzu 
Published: July 2023

Abstract
In the present study experimental observations of swirling fires were undertaken based on self-generated swirling flows to study some aspects of the whirling fires typically found in large urban and forest fires. The swirl was caused by channeling the entrainment flows caused by the fire itself located in a square enclosure with symmetrical open corner gaps. The stability characteristics in maintaining the integrity of the flame by the swirling flow were examined by modifying the channeled entrainment flows. Also studied were qualitative effects of different fuels, sizes of the fuel pan relative to that of the enclosure, and the wall gap sizes which permitted the generation of the swirling flows.
A 3-D Coupled Solution for the Flow and Fiber Orientation in Injection Molding of Fiber-Filled Systems
Authors: Kabanemi Kalonji K. , Hétu Jean-François , Garcia-Rejon Andrés 
Published: July 2023

Abstract
This paper describes a fully three-dimensional transient finite element method for calculating the flow behavior and fiber orientation during filling of injection molded parts. The fiber-fiber interaction is taken into account. The momentum and continuity equations are first solved with the viscoelastic stress treated as a fixed body force. The kinetic equation for the orientation tensor is then integrated with known kinematics using the standard Galerkin method. The calculation is performed on a time-dependent flow domain. Since the method is truly three-dimensional, singular regions such as the flow front or near injection gates and solid boundaries, where decoupled approximations are not valid, are naturally dealt with. The material anisotropy behavior is modeled by using the Doi-Doraiswamy-Metzner model. Numerical results, involving the Poiseuille flow and the filling of an end-gated plate, emphasizing the importance of the three-dimensional coupling calculations between the flow and orientation are presented.
On an Apparent Singularity in the Flow of Liquids Under High Shear Stress
Authors: Bair Scott , Khonsari M. M. 
Published: July 2023

Abstract
Examination of the equations governing the shear flow of laminar, incompressible, linearly viscous (Newtonian) liquids under high pressures reveals a singularity in the solution for the pressure gradient. This apparently unreported phenomenon is shown to occur in liquids whose viscosity, μ, increases exponentially with pressure, P, as μ = μoeαP, where α denotes the pressure-viscosity coefficient. For a two-dimensional configuration with the shearing action taking place in the x direction and with P = P(x,y), the singularity is shown to take place when: τyx=±1α1+α2τxxτyy, at which case both ∂p∂x and ∂p∂y→∞. The occurrence of such a singularity in the pressure gradient may have an important physical implication in lubrication flows particularly in concentrated contacts such as elastohydrodynamic lubrication of rolling element bearings and gears. Such a singularity may be the initiator of shear localization (shear bands) which have been recently observed experimentally.
Transient Response of Microchannel Heat Sinks in a Silicon Substrate
Authors: Rujano José R. , Rahman Muhammad M. 
Published: July 2023

Abstract
The transient conjugated heat transfer in forced convection for simultaneously developing laminar flow inside a microchannel heat sink is studied by solving the steady momentum equation and the transient energy equation. A parametric study is performed to understand the effects of channel depth and width, Reynolds number, spacing between channels and solid to fluid thermal conductivity ratio. Silicon as well as indium phosphide are used as wafer’s material. Step and pulsed variations of the heat load are analyzed. Results show that the time required for the heat transfer to reach steady state condition is longer for the system with larger D and S or smaller Re and W. Characteristics results for the fluid mean temperature at the exit, solid maximum temperature, local Nusselt number, and local heat flux are presented graphically as functions of position and time.
Thermoeconomic Analysis: A Criterion for the Selection of Cogeneration Systems
Authors: Luz-Silveira J. , Balestieri J. A. P. , Santos A. H. M. , Almeida R. A. 
Published: July 2023

Abstract
The economical viability of three cogeneration schemes as supplying alternatives for a hypothetical industrial process has been studied. A cost appropriation method based on Valero’s studies (1986) has been used. This method enables the determination of exergetic flows, the Second Law efficiency of equipment and the monetary costs of the products acquired by the industrial process (steam and electrical energy). The criterion adopted for the selection is the global cost of the supplied products to the industrial process as regarding in Brazilian conditions.
Thermodynamic Analysis of Injected Water Recovery Systems for the Humid Air Turbine (HAT) Cycle
Authors: Bidini Gianni , Desideri Umberto , Di Maria Francesco 
Published: July 2023

Abstract
The Humid Air Turbine (HAT) cycle is an inter-cooled gas turbine cycle, having an air-water mixing evaporator before the combustion chamber, and a heat recovering system for the exhaust gases. The considerable amount of water consumed in the mixing evaporator (about 1200–2400 m3 daily for a 100 MW unit), represents a significant drawback to the use of the HAT cycle as well as of other steam injected gas turbines. In fact, this means high operational costs for water treatment, and eventual legislative restrictions limiting the use of water, not to mention the environmental impact of the depletion of water resources.
The aim of this paper is to evaluate the changes in the performance of the HAT cycle when a water recovery system is added in the exhaust gases, and to determine the heat exchangers conditions for maximum water and heat recovery. Finally, the size of a surface condenser for water recovery is determined for a given HAT cycle power output.
The results show the possibility to recover up to 85% of the consumed water and up to 30% of input heat from the condensation of the water contained in the exhaust gas. The paper also examines all the thermodynamic processes in each cycle component from the viewpoint of recovering water from the exhaust gas. Since part of the water contained in the exhaust gas is due to the inlet air humidity and the combustion process, the relative amounts of water and their contributions to the overall heat recovery are also calculated.
Thermodynamic Analysis of High Temperature Fuel Cells: Methane Reforming
Authors: Call Frederick W. 
Published: July 2023

Abstract
The endothermic or exothermic processing of methane to a suitable fuel for fuel cell applications wastes exergy, the ability to produce electricity. The paper proposes a fuel cell process that converts (waste) heat (251 kW) into power (214 kW) while the methane (752 kW) is being reformed. Much more heat is processed than might be anticipated from the small values of enthalpy increase (37 kW) or the availability loss (36 kW) of the (endo-) thermochemical reaction. The resulting watergas (789 kW) can be used in an ordinary fuel cell, in co-generation, or as a chemical feed stock. A practical compromise is suggested and comparison is made to standard reforming methods.
Thermodynamic Evaluation of a Single-Flash Geothermal Power Plant in Nevada
Authors: Kanoglu Mehmet , Çengel Yunus A. , Turner Robert H. 
Published: July 2023

Abstract
First and second law analysis of a 12.5 MW single-flash design geothermal power plant in Nevada is performed using actual plant data, and alternatives are investigated to improve its performance. Exergy destruction throughout the plant is quantified and illustrated using an exergy cascade. The major source of exergy destruction is reinjection of brine after its separation from the steam. It accounts for 48.5% of total exergy destruction. The first and the second law efficiencies of the plant are calculated to be 5.7% and 21.6%, respectively, based on the exergy of the geofluid at downwell. These values seem to be very low. The analysis of alternative designs are based on the exergy analysis. Among the alternatives investigated, a double-flash design would increase the net power output by 4.5 MW (or 36%), depending on the secondary flash pressure chosen. The combined single-flash/binary design would increase the net power output by about 5.0 MW depending on the working fluid chosen.
Longitudinal Transition Maneuvers in an Automated Highway System
Authors: Connolly Thomas R. , Hedrick J. Karl 
Published: July 2023

Abstract
The control structure for automated vehicles in an Automated Highway System is based on the idea of multiple-surface sliding control. The “upper” surface determines a desired net torque while the “lower” surface determines the required throttle angle or brake pressure needed to achieve the desired torque. This paper presents an upper surface control law for performing longitudinal transition maneuvers. The maneuvers use desired velocity trajectories which are based on maintaining safety and comfort throughout the maneuver. The control law chosen is a sliding controller due to the non-linearities in the dynamics and the uncertainties in the parameters. Adaptive techniques were also implemented to help improve the velocity tracking. The controller was implemented on experimental vehicles and tested at highway speeds.
Worst-Case Evaluation Methods for Vehicle Control Systems
Authors: Ma Wen-Hou , Peng Huei 
Published: July 2023

Abstract
Worst-case evaluation method for vehicle control systems is studied in this paper. Depending on the control system information structure, we divide the worst-case scenario generation problems into four categories: one-player without preview, one-player with preview, two-player without preview, and two-player with preview. A passenger vehicle under automatic steering control was used as the target system to be analyzed. Numerical simulations and frequency domain analysis were performed to study the effectiveness of the proposed disturbance generation algorithms.
Theoretical Analysis of Punch Speed and Blank Holder Force Control in Deep Drawing Process of Strain-Rate-Sensitive Materials
Authors: Manabe Ken-ichi , Yoshihara Shoichiro , Nishimura Hisashi , Shibata Akinori 
Published: July 2023

Abstract
Various factors affecting the variable blank holder force (BHF) and punch speed in the circular cup deep-drawing process with forming-speed-dependent characteristics were analyzed in order to determine the optimal control conditions of the process and the effects on the permissible range of forming conditions. The isotropic blank material was assumed to exhibit strain hardening and strain-rate-sensitive characteristics given by σ = Kε˙mεn. Effects of material properties and process variables on the fracture and wrinkle limit BHF curves were simulated using an elementary analytical method. The simulated results show that the acceptable drawing range of highly strain-rate-sensitive materials strongly depends on the punch speed. It is confirmed theoretically that there is an optimal process control path in the acceptable range of the punch speed-BHF-drawing progress space even beyond the critical constant punch speed. Based on these results a new concept of optimal process control with variable punch speed and BHF control is proposed in order to reduce the forming time, improve the quality of the products and reduce the number of defective parts produced.
A Real Time Quintic Spline Interpolator for an Open Architecture Machine Tool
Authors: Wang Fu-Chung , Schofield Steven , Wright Paul K. 
Published: July 2023

Abstract
In this paper, we describe a new quintic spline interpolator for real time trajectory generation during free form curve machining on an Open Architecture machine tool platform. The research provides new capabilities for advanced CAD/CAM systems.
Complicated curves and shapes designed in a CAD system are usually represented by a set of discrete data points. Subsequently, for manufacturing by a CAM system, these data points need to be converted into tool paths for machining. Therefore, the paper presents a new interpolation method that interpolates the designated data points with a quintic spline curve for real-time tool path generation. The resultant curve, generated by the proposed interpolation method, is nearly arc-length parametrized and has C3 continuity. The near arc-length parametrization property makes the real time generation of the reference commands of the cutting tool path easier. The C3 continuity guarantees the smooth motion of continuous speed, acceleration and even jerk during the machining. The combined properties of this new interpolation method enable a new quintic spline interpolator to be developed for real time tool path generation.
Noise Optimal Control in a Fluid-Floated Magnetic Positioner
Authors: Ludwick Stephen J. , Trumper David L. 
Published: July 2023

Abstract
This paper describes the design of a noise-optimal controller in the context of an electromagnetically levitated motion control stage. In the stage, position is controlled in all six rigid-body degrees of freedom using electromagnets to provide the necessary forces. The moving element is surrounded by a fluid that forms squeeze film dampers between the moving and stationary portions of the stage. At the bandwidths of interest, the damping dominates the system dynamics, and so the plant is modeled as a mass-less damper. This stage provides the impetus for the development of a noise-optimal controller. Sensor noise and plant disturbance forces limit the achievable resolution of the stage. In order to understand this problem, we develop our analysis in the context of a single degree-of-freedom system. This is done in order to most simply show the key tradeoffs in this damper-dominated design. We then show how this model can be used in practice by quantifying the major noise sources present in our actual hardware and then applying this analysis to the control of the six degree-of-freedom stage. Experimental results from this stage verify the theoretical results.