bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a Modal Solution Library for the Transverse Vibration of a Thick Beam
Authors: Ayorinde Emmanuel O. , Zheng Zhiyang 
Published: July 2023

Abstract
The authors apply a method of obtaining the modal solutions for the free lateral vibrations of a thick rectangular orthotropic plate where through-the-thickness shear and rotary inertia are important. The approach (Ayorinde, 1995) utilizes optimized modes and is based on the application of the Rayleigh method to the Timoshenko beam. The plate solution was synthesized from those of beams in the two transverse directions. With as few as three optimized modes this method is of comparable accuracy with other methods employing 36 (six per direction) modes. and thus presents a significant advantage. Nevertheless, obtaining the thick beam frequencies involves the numerical solution of complicated hyperbolic equations, which takes much more computer time than for a thin beam. There are many important procedures that require the results of this “forward” problem. Examples are the material identification and damage characterization of thick plates. Since such procedures could utilize literally thousands of trial solutions of the forward problem, methods of significantly expediting the forward solution are of great importance. In this work an intensive investigation has been made of tile parameter space of elastic constants and geometries for thick plates for the behavior of the fundamental (2.2) mode, which is usually the most important structural mode, obtaining definitive guidance that the feasible approach is the setting up of a solution library for a thick beam rather than for a plate directly. The thick beam solution library is actually developed and an interpolation algorithm set up. The library is utilized for the forward plate problem. Results with and without the library are compared, and they confirm the accuracy and significant time-economy of the beam solution library approach.
Flow of a Power-Law Fluid in a Distorted Annulus
Authors: Letelier Mario F. 
Published: July 2023

Abstract
The velocity field is analytically determined for the case of power-law fluid axial flow in non-circular annuli, in which the inner wall is essentially circular, and the outer wall may exhibit a wide variety of shapes. The flow is assumed driven by the axial motion of the inner wall.
A perturbation scheme is developed for power-law indices close the unity. The analysis is pursued for two specific shapes of the cross-section outer wall. By assigning appropriate values to the shape parameters, the two annulus shapes herein presented show three, and four, respectively, curved sides that generate, correspondingly, three, and four corners.
Plots of isovels and velocity profiles are shown for several values of the significant parameters. Relationships between pipe geometry, fluid constants and flow velocity are discussed.
Laminar Axisymmetric Recirculating Flow of a Nonlinear Viscoplastic Fluid
Authors: Hammad Khaled J. , Otugen M. Volkan , Vradis George C. , Arik Engin B. 
Published: July 2023

Abstract
The laminar flow of a nonlinear viscoplastic fluid through an annular sudden expansion was investigated experimentally. In addition to a yield-stress shear-thinning fluid, the flow of a Newtonian fluid through the same expansion was also studied to form a baseline for comparison. Velocity vectors were measured on the vertical center plane using digital particle image velocimetry (PIV). From these measurements, two-dimensional contours of axial and radial velocity as well as the stream function were calculated covering the separated, reattached and redeveloping flow regions. The Reynolds number range was Re = 1.8 to 31, based on the upstream pipe diameter and bulk velocity, and the corresponding yield number range for the non-Newtonian fluids was Y = 0.28 to 1.22. The results obtained for a power-law index of n = 0.68 indicate the existence of two distinct flow regimes as the Reynolds number increases and the yield number decreases. For a combination of low Reynolds numbers and high yield numbers, a non-moving fluid zone is observed immediately downstream of the step and no separated flow zone exists. For the higher Reynolds number and the lower yield number flow, a separated flow zone does exists downstream of the expansion step, which is followed by flow reattachment characterized by a three-dimensional zone of stagnant fluid.
The Evolution of Planar and Axisymmetric Yield / Power-Law Jets
Authors: Jafri Ijaz H. , Vradis George C. 
Published: July 2023

Abstract
The evolution of a steady, incompressible, non-isothermal submerged jet of a non-Newtonian yield/power-law fluid jet is studied using a numerical solution of the governing boundary layer equations. Emphasis is placed in studying the effects of the governing non-dimensional flow parameters i.e. the yield number, power-law index, and Prandtl number. Both yield-pseudoplastic and yield-dilatant fluids are studied for planar and axisymmetric geometries. Decay histories of the jet’s center-line velocity and temperature as well as the spread of the half-width of the jets are obtained. These results show that the jet evolution, as described by the decay of the centerline velocity and evolution of the jet’s half-width, becomes independent of the power-law index at higher yield numbers. The jet expansion boundary is concave to the jet-axis for all values of the power-law index for fluids that exhibit a yield stress. Moreover, the results depict the near independence of the decay of the centerline temperature from the power-law index. Also, it is established that for fluids exhibiting yield, mixing is much more rapid as compared to that of yield-stress free fluids.
Analysis of Slurry Flow Into a Slot
Authors: Clark Peter E. , Zhu Qinsheng 
Published: July 2023

Abstract
Since the paper by Cleary and Fonesca in 1992, there have been several attempts to determine if convection is an important factor in prop-pant placement. Papers by Clark and Courington, Clark and Zhu, and Barree and Conway have provided important clues, but the primary question remains unanswered. To address these questions, we have returned to the question of scaling in models. As mentioned in JPT paper (March 1995) by Clark and Zhu, scaling in a slot-flow model is difficult because each of the possible scaling factors (Reynolds number, velocity, shear rate and pressure drop) have a different dependence on width. Because of this, our initial model was scaled on shear rate and therefore flowing viscosity. Further examination of the problem lead us to believe that the ratio of the forces available to push the fluid in the horizontal and vertical directions is extremely important in determining whether or not convection is observed. This paper will discuss the development of two dimensionless groups that can be used to predict convection and the experimental evidence that validate these dimensionless group.
The Motion and Interaction of Solid Particles in Viscoelastic Liquids
Authors: Feng J. , Joseph D. D. , Huang P. Y. 
Published: July 2023

Abstract
In this paper we present numerical and experimental results on the motion and interaction of solid particles in polymeric fluids. The two-dimensional numerical work investigates the viscoelastic effects on the sedimentation of a particle in the presence of solid walls or another particle. The Navier-Stokes equations coupled with an Oldroyd-B model are solved using a finite element method, and the particles are moved according to their equations of motion. In a vertical channel, a particle settling close to one side wall experiences a repulsion from the wall; a particle settling farther away from the wall is attracted to it. Two particles settling in tandem attract and form a doublet if their initial separation is not too large. Two particles settling side by side approach each other and the doublet also rotate till the line of centers is aligned with the direction of fall. The experimental part studies the behavior of single particles and suspensions in polymer solutions in a torsional flow. Four issues are investigated: the radial migration of a spherical particle, the rotation and migration of a cylindrical rod, the particle-particle interaction and microstructures in a suspension of spheres and the microstructures in a suspension of rods. A spherical particle migrates outward at a constant velocity unless the polymer solution is very dilute. A rod has two modes of motion depending on its shape, initial orientation, the local shear rate and the magnitude of normal stresses in the fluid. When a suspension is sheared, spheres form chains along the flow direction. These chains may connect and form circular rings, which migrate outward at a velocity much higher than that for a single sphere. Rods interact with each other and aggregate in much the same way, but to a less extent than spheres. Particle interaction and aggregation can be explained by two fundamental mechanisms discovered in the numerical simulations of sedimentation.
Effect of Process Parameters on the Rheological Properties of O/W Emulsions
Authors: Gallegos C. , Sánchez M. C. , Guerrero A. , Franco J. M. 
Published: July 2023

Abstract
An overview of the effects that different processing conditions have on the rheology and droplet size distribution of o/w emulsions containing different macromolecular and low molecular weight emulsifiers is presented. The processing variables studied were emulsification time, agitation speed, temperature of emulsification, previous thermal treatment of the continuous phase and type of device used. Generally, an increase in the energy input during emulsification yields lower values of the mean droplet size, but does not always improve the viscoelastic properties of the emulsion. Thus, the bulk rheology of the emulsions may also be influenced by the phase behavior of the surfactant-water system, or by changes in the structural conformation of proteins. These influences are easily changed by modifying the temperature of emulsification or by a pre-emulsification thermal treatment of the continuous phase, which affect the microstructure of the emulsion and, subsequently, its linear viscoelastic behavior.
Microstretch Fluid Description of Fluidized Beds
Authors: Delassade Xavier A. 
Published: July 2023

Abstract
The specific purpose of this work is to consider the effect of particle inertia and other consequences of non-negligible spatial gradients of velocities and concentration, voidage, on vertically propagating concentration waves of small amplitude. The form of the momentum equations for one-dimensional unsteady mean motion of solid particles in a gas-fluidized bed is established. The fluidized bed is considered as a mixture of a microstretch fluid representing the particulate phase, and a classical Newtonian fluid. The constitutive relations expressing the contribution of the interaction forces in terms of phase velocities and the micro-inertia of the particles are given.
Voidage disturbances are briefly studied via nonlinear wave analysis. A fifth order Burgers-Korteweg-de Vries equation is derived. Accordingly, the linear stage of instability of a fluidized bed is replaced by a nonlinear stage in which voidage disturbances are represented by slowly amplifying soliton or radiating soliton pulses.
Influence of the Conductivity of the Oil on the Electrorheology of Zeolite/Mineral Oil Suspensions
Authors: Wu C. W. , Chen Y. , Conrad H. 
Published: July 2023

Abstract
The effect of the conductivity of various mineral oils on the dc current density and electrorheology (ER) of suspensions (ϕ = 0.28) of zeolite particles in these oils was determined at 25°C and a shear rate γ˙=2s-1. The measured electric field (E) dependence of the conductivity of the oils was in accord with the modified Onsager equation for nonpolar liquids, which givesσf(E)=σf(0)[(1-A)+Aexp⁡(E/Ec)1/2] where σf(0), A, and Ec are constants. The electric field dependence of the Onsager dissociation parameter b was evaluated. The current density and yield stress of the suspensions were in reasonable accord with those predicted by the conduction model for ER behavior. The effect of heating on the conductivity of the two oils which exhibited the lowest and highest current density was determined.
The Response of an Electrorheological Fluid to a Step Change in Applied Voltage in Dynamic Squeeze Flow
Authors: El Wahed Ali K. , Sproston John L. , Stanway Roger 
Published: July 2023

Abstract
This paper is concerned with an experimental investigation of the performance of an ER fluid in oscillatory squeeze-flow and the development of a quasi -steady theoretical model in which the rheological behaviour of the fluid is assumed to follow a bi-viscous shear stress/shear rate characteristic. The fluid is sandwiched between two parallel plane circular electrodes, the upper one fixed and the lower one oscillating normal to its plane. Of particular interest are the results of an experimental assessment of the response of the fluid to a step change in applied voltage and the effect of a change in the size of the solid phase.
Fully Conservative Forms of a System of Unified Electro-Magneto-Hydrodynamic Equations
Authors: Dulikravich George S. , Jing You-Hao 
Published: July 2023

Abstract
A system of partial differential equations governing unsteady multidimensional electro-magneto-hydrodynamic flows has been rewritten in its fully conservative (divergence-free) form. Linear polarization and magnetization effects were allowed while assuming an incompressible fluid and a single type of electrically charged particles in the flow. Both vector operator formulation and a scalar Cartesian coordinate system formulation have been derived in detail. The resulting fully conservative forms are suitable for further transformations to other coordinate systems or for direct discretization leading to their numerical integration.
Centrifugal Compressors for Automotive Air Conditioners: Component Design
Authors: Yun Hayong , Smith Joseph L. 
Published: July 2023

Abstract
The application of a novel, electric motor-driven, variable-speed centrifugal compressor for automotive air conditioners has been investigated.
For the feasibility analysis, a configuration design has been performed. It includes refrigerant selection, thermodynamic cycle analysis, compressor aerodynamic design, and mechanical layout of the integrated motor-compressor structure. Both the motor constraints (provided by the Laboratory for Electromagnetic and Electronic Systems at M.I.T.) and the compressor constraints were considered for the configuration design.
The result is an inter-cooled two-stage compression system using R123 as the refrigerant. The inter-cooling is achieved by feeding back a small fraction of the condenser liquid into the return channel between the first and the second stage through the electric motor. At the design condition, the pressure ratio is 3.2 for the first stage and 1.9 for the second stage. The design rotational speed is 75,000 rpm, and the maximum cooling capacity is 5,275 Watts.
High efficiency is expected by varying the compressor speed to match the required cooling load at each instant.
Centrifugal Compressors for Automotive Air Conditioners: System Design and Operation Strategy
Authors: Yun Hayong , Smith Joseph L. 
Published: July 2023

Abstract
System designs and operation strategies for a motor-driven, variable-speed compression system (described in the companion paper) have been developed.
Systems which can cover the required range of operating conditions (i.e. various cooling loads) have been designed. They require a compromise between high efficiency at high cooling loads and compressor surge prevention at low cooling loads.
Therefore, compressor operation strategies consist of a variable speed strategy for stable operating points (to match the cooling load at any instant) and a compressor stabilization strategy (to prevent compressor surge instability at low cooling load operations) for unstable operating points.
The system design and the operation strategy study results indicate that the novel compression device can improve the overall system efficiency by matching the compressor characteristics with the rest of the air conditioning system.
An Approach for the Calculation of Compression Loads in Helical Twin Screw Compressors
Authors: Qin Zhaohui , Adams Glynn P. 
Published: July 2023

Abstract
The main components of a twin screw compressor are two helical rotors. Its complicated geometry makes it difficult to compute the forces and moments induced on each rotor due to the compression process, the compression loads. However, the compression loads are an important consideration in the design and analysis of twin screw compressors. In this paper, a numerical method is presented for computing the compression loads by integrating the pressure over the rotor surface. Vector calculus and numerical integration schemes are implemented to calculate the compression loads in order to obtain a robust procedure that can be applied to arbitrary rotor profiles. The calculated results are given for a specific compressor configuration in terms of the compression loads as a function of the rotor angular position. It is shown that the rate of change of the profile radius as a function of the angular coordinate is an important factor affecting the accuracy of the integrations.
Entropy Generation in Multicomponent Reacting Fluid Flow With Heat and Mass Transfer
Authors: Teng Ho , Kinoshita Charles M. , Masutani Stephen M. 
Published: July 2023

Abstract
A comprehensive equation to determine the rate of local entropy generation in multicomponent, reacting, laminar fluid flow involving heat and mass transfer is formulated based on species-average velocity in a multicomponent continuum. The entropy-generation equation developed in this study suggests that species diffusion induces a diffusive-viscous effect, heretofore not reported in the literature, which could contribute significantly to entropy generation in multicomponent fluid systems, and that entropy generation in a multicomponent system exceeds that in a single-component fluid system having similar velocity and temperature distributions because a greater number of irreversible processes, such as species diffusion, chemical reaction, and the Soret and Dufour effects, are involved. Under appropriate conditions, if the diffusive-viscous effect is neglected, the entropy-generation equation of this study reduces to those reported in the literature for simpler fluid systems based on mean flow.
Development of Constrained Equilibrium Codes and Their Applications in Non-Equilibrium Thermodynamics
Authors: Bishnu Partha S. , Hamiroune Djamel , Metghalchi Mohamad , Keck James C. 
Published: July 2023

Abstract
Two constrained equilibrium codes, GNASA and GSTANJAN, have been developed which determine the composition of constrained equilibrium gas mixture. These codes use NASA and STANJAN equilibrium programs as the basis for generalized equilibrium routines. Gas mixture composition is determined by minimizing Gibbs free energy of the mixture subject to any specified constraints in addition to elemental constraints. Performances of these two codes have been compared to each other and it has been found that GSTANJAN converges over a wider range of constraints while the convergence of GNASA is limited. These codes have been applied in non-equilibrium evolution process of hydrogen-oxygen or H/O mixture. The non-equilibrium process has been modeled by using only two constraints in addition to elemental constraints. The results are in good agreement with detailed kinetic solution.
Local Optimization of Energy Systems
Authors: Lozano Miguel Angel , Valero Antonio , Serra Luis 
Published: July 2023

Abstract
Many thermal systems are very complex due to the number of components and/or its strong interdependence. This complexity makes difficult the optimization of the system design and operation. The Theory of Exergetic Cost is based on concepts such as resources, structure, efficiency and purpose (belonging to any theory of production) and on the Second Law.
This paper will show how is it possible to obtain from the theory of exergetic cost the marginal costs (Lagrange multipliers) of local resources being consumed by a component. This paper also shows the advantage of the proposed Theory of Perturbations when describing the complexity of structural interactions in a straightforward way. This theory allows to formulate simple procedures for local optimization of components in a plant.
Finally strategies for optimization of complex systems are shown. They are based in the sequential optimization from component to component. This clear and efficient method comes form the fact that we have now an operative application of the Thermoeconomic Isolation Principle.
Exergy Analysis of a Fuel Cell Power System for Transportation Applications
Authors: Cownden Ryan , Nahon Meyer , Rosen Marc 
Published: July 2023

Abstract
An exergy analysis of a solid polymer fuel cell power system for transportation applications is reported. The analysis was completed by implementing the derived fundamental governing second law equations for the system into a fuel cell performance model developed previously. The model analyzes all components of the system including the fuel cell stack and the air compression, hydrogen supply, and cooling subsystems. From the analysis, it was determined that the largest destruction of exergy within the system occurs inside the fuel cell stack. Other important sources of exergy destruction include irreversibilities within the hydrogen ejector and the air compressor, and the exergy emission associated with the heat rejected from the radiator. To increase the accuracy of the model and extend the results, a more comprehensive model for the fuel cell stack should be developed, and an investigation should be performed into the effects of varying the operating parameters of the system. The results may aid efforts to optimize fuel cell systems.
Performance of a Hybrid Photovoltaic Thermal Solar Collector
Authors: Sopian K. , Liu H. T. , Kakac S. , Veziroglu T. N. 
Published: July 2023

Abstract
Closed form solutions have been obtained for both a single-pass and a double-pass collectors and, for a passively cooled photovoltaic panel. The mean plate temperature, photovoltaic cell, thermal, and combined efficiencies have been obtained. The results show that the double-pass photovoltaic thermal collector has a more productive cooling effect compared to the single-pass photovoltaic thermal collector, and thus has better photovoltaic cells performance. The effect of the mass flow rate, duct depth, and packing factor on the photovoltaic cell performance are also discussed.
Three-Dimensional Absorption Process in Aqua-Ammonia Absorption Refrigerators Using Helium as Inert Gas
Authors: Kouremenos D. A. , Stegou-Sagia A. , Antonopoulos K. A. 
Published: July 2023

Abstract
In order to eliminate the danger of a possible explosion in neutral gas NH3/H2O absorption refrigerators using hydrogen as the inert gas, helium can be used as a substitute.
A numerical procedure is presented for the calculation of the absorption process. In previous studies the problem was simplified by considering the circular absorption tube in a vertical position with the liquid NH3/H2O stream being of annular cross section, thus resulting in a two-dimensional situation. In the present study the three-dimensional heat and mass transfer process is considered, in which the absorption tube is nearly horizontal and the liquid NH3/H2O stream has a circular meniscus cross-section.
The developed procedure which is based on a finite-difference solution of the three-dimensional momentum, energy and mass transport differential equations, may be used in the design of absorbers for inert gas absorption refrigeration units. It is concluded that helium behaves similarly to hydrogen and therefore it can replace it, in order to eliminate the danger of an explosion.