bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermionic Cascade Converter Concept for High-Efficiency Space Power
Authors: Begg Lester L. , Van Hagan Thomas H. , Smith Joe N. 
Published: March 2022

Abstract
This paper presents trade studies that address the use of the thermionic/AMTEC cell — a cascaded, high-efficiency, static power conversion concept that appears well-suited to space power applications. Both the thermionic and AMTEC power conversion approaches have been shown to be promising candidates for space power. Thermionics offers system compactness via modest efficiency at high heat rejection temperatures, and AMTEC offers high efficiency at modest heat rejection temperature. From a thermal viewpoint, the two are ideally suited for cascaded power conversion: thermionic heat rejection and AMTEC heat source temperatures are essentially the same. In addition to realizing conversion efficiencies potentially as high as 35–40%, such a cascade offers the following perceived benefits:
• Survivability — capable of operation in the Van Allen belts.
• Simplicity — static conversion, no moving parts
• Long lifetime — no inherent life-limiting mechanisms identified
• Technology Readiness — Large thermionic database; AMTEC efficiencies of 18% current being demonstrated, with more growth potential available
• Technology Growth — applicable to both solar thermal and reactor-based nuclear space power systems
Mechanical approaches and thermal/electric matching criteria for integrating thermionics and AMTEC into a single conversion device are described. Focusing primarily on solar thermal space power applications, parametric trends are presented to show the performance and cost potential that should be achievable with present-day technology in cascaded thermionic/AMTEC systems.
Analysis and Evaluation of Malfunctions in Thermomechanical Systems
Authors: Royo Javier , Zaleta Alejandro , Valero Antonio 
Published: March 2022

Abstract
In previous papers, two new parameters related to the performance of thermal components have been shown: the internal parameters θ (Royo and Valero 1995) and the dissipation temperature (Royo et al. 1996).
When the behavior of a component of a thermal plant is impaired due to internal deteriorations, cause a modification in the behavior of another components. This implies a variation in the global efficiency of the plant. But how can this influence be quantified? This question is of utmost importance when it comes to making an energetic and economic assessment of carrying out a repair on a component, or undertaking an improvement on such a component.
The aim of this paper is to show an example of the use of the internal parameters 9 and the dissipation temperatures to answer analytically this question. The example chosen is a power plant with reheating.
Analytical and numerical results and their analysis are provided in the paper. For example, using this procedure, it is possible to obtain that, in the chosen plant, a diminution of 1% in the isoentropic efficiency of their high pressure steam turbine causes 0.13% diminution in the efficiency of the whole plant.
The results obtained have been checked by means simulation (GATE Cycle 1995). The difference between both set of results are in all the cases lower than 4%.
Performance Evaluation of a Binary Geothermal Power Plant in Nevada
Authors: Kanoglu Mehmet , Çengel Yunus A. 
Published: March 2022

Abstract
First and second law analysis of a 12.9 MW binary geothermal power plant in Nevada is performed using actual plant data obtained in 1996, and alternatives are investigated to evaluate its performance. Exergy destruction throughout the plant is quantified and illustrated using an exergy cascade. The primary sites of exergy destructions are the turbine-generator assembly where power is generated, the condenser where the working fluid is condensed, and the reinjection well where the brine is reinjected into the ground after passing through heat exchangers. The exergy destruction at these sites account for 30.5%, 26.4%, and 21.4% of total exergy destruction in the plant, respectively.
The first and second law efficiencies of major plant components are determined in an attempt to assess their individual performances. The overall first and the second law efficiencies of the plant are calculated to be 5.6%, and 26.9%, respectively, based on the exergy of the geothermal fluid at reservoir, and 5.9%, and 29.2%, respectively, based on the exergy of the geothermal fluid at wellhead. Thermodynamic analysis of alternative designs (single and double flash systems) indicates that the existing binary design is best suited for this site, and thus it should be preferred at similar sites.
A Thermodynamic Analysis of Fever in Chemotraphs
Authors: Annamalai K. , Morris T. , McNichols D. 
Published: March 2022

Abstract
Temperature regulation of chemotraphs (animals and humans) is one of the most sophisticated processes in nature. The basal condition is characterized as the absolute minimum energy state during consciousness. The conditions necessary are: no food for twelve hours, restful sleep, complete rest when awake, no excitement, and an ambient temperature of 20–27°C. The body’s metabolism of chemotraphs is constantly producing excess heat, even at rest that must be removed in order to maintain thermal equilibrium. Under normal conditions the heat produced by the bio-chemical reactions within the body must be the same as the heat loss. A first law analysis is conducted in determining the net rate of heat-loss while the body is at rest. The results are then compared with data obtained by physiologists for humans and checks to within 5%. The analysis is extended to predicting the occurrence of fever. Dimensional results are then presented for the body temperature vs time. Fever can occur either through increased slow oxidation/combustion (metabolic oxidation) of a mix of carbohydrates and fats, or by reduced heat-loss from the skin due to reduced blood flow (which causes shivers). If all the energy released during oxidation/combustion results in direct heat production then it is possible to predict I) temperature vs time, and ii) the initial metabolic rate from nasal exhaust measurements during initial periods of fever. Good agreement has been obtained between model results and experimental data on cats during heat-up periods.
The Influence of Fouling on the Heat Transfer Characteristics of Boiler Tubes: A Comparison Between a Numerical Simulation and an Industrial Test Case
Authors: Delle Site Corrado , Sciubba Enrico , Trissati Marco 
Published: March 2022

Abstract
The paper presents a numerical simulation of the effects of fouling on a representative section of the vertical boiler tubes in a pulverised coal boiler for a thermoelectric power plant. The fouling, which in the real case is produced by agglomeration of sticky, low-melting ash deposits, unburned particulate and incombustibles on the gas side of the tube wall, is here simulated by a uniform coating of solid homogeneous material with average thermal properties derived by experimental data. Both heat transfer modes (convection and radiation) are simulated in the numerical calculation, that has been performed via a commercial finite-element code, FIDAP of FDI Inc.
After a two-dimensional numerical test, necessary to calibrate the simulation parameters and to determine a suitable mesh, a fully three dimensional simulation was carried out. Full account has been taken of the properties of the real fluid (the hot gas is assumed to be viscous, Newtonian and homogeneous) and of the real characteristics of its flow (fully turbulent and subject to strong radiation effects). The heat transfer in the coating and in the tube wall has been calculated without introducing heat exchange coefficients, but imposing instead a well-established heat transfer correlation for the boiling water side. Turbulent effects have been simulated using a modified k-ε model. Periodic flow in the vertical direction and forced velocity on the core side have been imposed as boundary conditions.
The results of the numerical computation are compared with those of an extensive experimental campaign conducted in 1992 on an industrial boiler for a pulverised coal, 240 MW power plant: the steam conditions at design point are 17 MPa and 540°/540°C. It is shown that the numerical results agree very well with the experimental data for the selected test section: it is therefore proposed to extend the generality of the numerical simulation to implement and complete the results of future tests on the effects of fouling.
A Study of a Refrigeration Cycle Driven by a Liquid Refrigerant Injected Compressor
Authors: Yanagisawa Tadashi , Fleming John S. , Dutta Asit K. , Fukuta Mitsuhiro 
Published: March 2022

Abstract
The performance of a refrigeration cycle driven by a liquid refrigerant injected compressor is investigated to examine its energy saving characteristics and performance improvement. Mathematical models of the compressor, the condenser and their combination in a complete cycle are used. The model shows an increase of the suction mass flow, an associated increase of the compression power and a small change of the overall efficiency due to the reduced temperatures of the refrigerant discharge and the compressor body. A condenser fed with refrigerant of lower superheat and greater mass flow shows an improvement in performance due to an increase in the two-phase region, though the improvement depends on the secondary fluid flow conditions. The thermal capacity and coefficient of performance of the total cycle increases with the injection ratio due to the combined effects of the compressor and the condenser.
Innovative High Temperature Lift Heat Pump Technologies for Industrial Processes
Authors: Olszewski Mitch , Zaltash Abdi 
Published: March 2022

Abstract
The process integration approach has been extended with a plant utility emphasis by the Department of Energy (DOE) Industrial Heat Pump (IHP) Program. In this approach, reject heat from a process is upgraded to plant utility conditions and fed into the plant distribution system. Therefore, the reject heat from any process can be used as input and the output can be used at any location within the plant. With this design philosophy, the unit can be easily integrated into existing industrial applications, and all reject heat streams become potential targets of opportunity.
The plant utility approach cannot be implemented without heat pumps with high-lift capabilities (on the order of 150°F or 83°C). Currently available heat pumps have only about half the lift capability required. Thus the current emphasis for the DOE IHP Program is the development of high-lift chemical heat pumps that can deliver heat more economically to higher heat delivery temperatures. This paper details the proof-of-principle of innovative process cooling (refrigeration) and process heating technologies that are based on advanced cycles and/or advanced working fluids. In addition, it discusses the current status of the program to develop economically competitive, environmentally acceptable heat pump technologies that are capable of providing the delivery temperature and lift required to supply industrial plant utility-grade process heating and/or cooling.
Feasibility Study on Using Cooling Capacitance From Ice Storage System to Save Energy Costs of Operating Chiller AC System
Authors: Li Shan S. 
Published: March 2022

Abstract
This paper discusses the economical feasibility of various ways to apply the cooling capacitance from an ice storage system to a chiller air-conditioning system. A parameter of equivalent energy efficiency is defined for the ice-assisted chiller system, and a validity criterion is proposed to judge the feasibility.
Several possible ways of applying the ice storage cooling source are described. By using the proposed methodology, a case study via computer simulation is conducted. In this simulation, the validity criterion is so chosen that the improvement to the chiller system would be economically equivalent to increase a chiller efficiency from 0.55 kW/ton to 0.47 kW/ton.
A discussion of the simulation results is given. Under the assumed working conditions, to apply the cooling resources to the condensation process or to the liquid line sub-cooling is difficult to be economically feasible. The only better way to use the cooling resource is to cool the chilled water directly. However, in the best case, this system configuration would become one of the working modes of an ice storage system.
Two-Temperature Integral Analysis of a Compressor-Driven Metal Hydride Heat Pump
Authors: Lloyd George M. , Razani A. , Kim K. J. , Feldman K. T. 
Published: March 2022

Abstract
An integral method is used to analyze the performance of a complete system model of a compressor-driven metal hydride heat pump. CFD studies incorporating the transient non-isothermal fully compressible nature of such systems have confirmed that high specific powers and COPs comparable to vapour compression cycles are achievable. Finite-time thermodynamic studies focusing on specific aspects of external heat exchanger design have identified the need for less computationally intensive models which include in a detailed manner all parasitic thermal losses as well the capability of capturing the thermal phase lags which occur between the reactors and the heat exchangers during steady-state operation. This paper develops a rigorous intermediate model which captures these effects. Parametric studies are presented as well as comparision with data from a prototype device.
Compression Simulation, Heat Transfer and Work in Reciprocating Type Refrigeration Compressors
Authors: Chatzidakis Sot. K. , Rouvas Alex. K. , Chatzidakis Kon. S. , Kouremenos Ath. D. 
Published: March 2022

Abstract
An experimental study has been undertaken to evaluate some theoretical studies on the compression and heat transfer process in reciprocating compressors. A two cylinder unit was equipped with suitable pressure sensors to measure and store the pressure-time function of the refrigerant. From the known geometry of crank-piston mechanism and the related thermodynamic relations the heat transferred between refrigerant and cylinder wall can be obtained. The position of the Top Dead Center can be defined either in a thermodynamic way or by a magnetic pick-up. The influence of the rotating speed is examined by taking measurements at different speeds. The results are compared to existing heat transfer relations to investigate their efficiency. The model used predicts with sufficient accuracy the heat transfer process.
Numerical Simulation of a Split-Blade Impeller Configuration of a Centrifugal Pump With Zero-Curvature Blades
Authors: Delle Site Corrado , Sciubba Enrico 
Published: March 2022

Abstract
This paper reports the results of a numerical study on the performance of several zero-curvature blade impeller configurations for centrifugal pumps. A “standard” zero-curvature blade impeller has been modified by introducing in the centre of the blade passage split-blades of different lengths and locations. The “standard” impeller configuration is a seven-blade impeller with inlet and exit flow angles of 22° and 66° respectively, rotating at 400 r.p.m..
The flow field in the impeller passage has been numerically investigated using a standard version of a finite element code (FEDAP of FDI Inc.); turbulence has been modelled with a two-equation, k-ε model which requires Van Driest’s wall functions to represent the law-of-the-wall profiles.
The flow is computed on a 2-D, blade-to-blade (S1) mean stream surface in the rotating reference frame. The numerical simulation has been carried out at nominal flow rate and at two off-design flow rates in order to obtain a portion of the pump characteristic.
A slight increase in e dynamic head is caused by the split-blade; a higher increase in pump head is obtainable by doubling the number of blades with respect to the standard configuration.
The velocity distributions at four radial sections of the impeller passage, the streamline contours and the hydraulic efficiency distribution for the different impeller configurations are compared and discussed.
Admittance Fluctuations and the Observed Acoustic Scattering From a Cylindrical Shell With Many Internal Oscillators
Authors: Bucaro Joseph A. , Romano Anthony J. , Sarkissian Angie , Photiadis Douglas M. , Houston Brian H. 
Published: March 2022

Abstract
This paper considers how the details of internally mounted mechanical oscillators are related to the acoustic scattering features observed in the measurements of Bucaro et al. (1997) and Photiadis et al. (1997). These measurements — the monostatic scattering as a function of frequency and angle from a submerged shell with many internal oscillators — have been interpreted (Bucaro et al., 1997) in the context of local admittance fluctuations caused by the presence of the oscillators. The theoretical basis for this effect is reviewed and specific details in the scattering spectrum are connected with certain shell/ oscillator parameters.
Reconstruction of Acoustic Pressure Fields Inside a Vibrating Cavity
Authors: Wu Sean F. , Yu Jingyou 
Published: March 2022

Abstract
This paper extends the Helmholtz equation least squares (HELS) method previously developed by Wang et aL [1995] and Wang and Wu [1997] to reconstruction of acoustic pressure fields in an interior region. In this methodology, the acoustic pressures are reconstructed through an expansion of acoustic modes, or a set of independent functions generated via an orthonormalization with respect to the particular solutions to the Helmholtz equation on the particular surface under consideration. The coefficients associated with these acoustic modes are determined by requiring the assumed form solution to satisfy the pressure boundary condition at the measurement points. The errors incurred in this process are minimized by the least squares method. Numerical examples of partially vibrating cylinders with two spherical endcaps at various half-length to radius aspect ratios and frequencies are demonstrated. The reconstructed acoustic pressures are compared with numerical solutions obtained by using a direct boundary element method.
Series Expansion for a Propagating Pulse
Authors: Cohen Leon 
Published: March 2022

Abstract
A new approach is presented for calculating the approximate intensity of a propagating pulse in a dispersive media. The method is based on first obtaining exact time dependent low order spatial moments and then constructing the density from these moments. The time dependent moments can be obtained explicitly from the initial spatial spectrum and the dispersion relation. The method of constructing approximate densities is based on a generalization of the traditional Edgeworth/Gram-Charlier methods.
Parameter Studies in the Optimal Design of Unconstrained Beam Damping Layer Treatments
Authors: Lumsdaine Arnold , Scott Richard A. 
Published: March 2022

Abstract
The aim of this paper is to examine the optimal shape of an unconstrained viscoelastic damping material on an elastic beam, and to examine how changing the volume of damping material affects the optimal shape. The optimization objective is to minimize the peak displacement of the beam at the first resonant frequency. The material loss factor is monitored to determine the improvement in performance between an initial, uniform layer shape and the optimized shape. A fine mesh validation model is created to verify the optimized shape. The ABAQUS finite element code is used to model the structures. Elasticity theory based continuum elements are used so that all stress effects are taken into account in the models. The optimization code uses a Sequential Quadratic Programming algorithm. Optimization studies are performed for a range of different damping layer volumes, from layers with 10% to 200% of the volume of the base layer. Results show that significant improvements in performance are obtained in all cases by optimizing the damping layer shape, up to 6000% in some cases. The amount of improvement achieved increases as the damping layer volume increases up to a point. At a certain point, however, (depending on the thickness of the base layer), the amount of improvement between a uniform damping layer and the optimal damping layer may actually decrease significantly.
Analytical and Experimental Characterization of Damping and Stiffness in Polymer Composites Having Coated Fibers as Reinforcement
Authors: Finegan Ioana C. , Gibson Ronald F. 
Published: March 2022

Abstract
Polymer composites have generated increased interest in the development of damped structural materials because of their low density, and excellent stiffness and damping characteristics. The objectives of this paper are to study the improvement and optimization of damping in fiber reinforced structural composite materials at the micromechanical level by coating some of the fibers with special polymers which have high damping. Since shear deformation is essential for viscoelastic damping in polymers, and large shear strains are generated near the fiber/matrix interface in composites, the use of special viscoelastic polymer fiber coatings is an effective way to improve damping in such composites. Of particular interest are hybrid composites having a mixture of coated and uncoated fibers, since coating all the fibers would cause unacceptable reductions in other important properties like strength and stiffness.
Fatigue Behavior of Resin Infusion Processed S2-Glass Woven Composites
Authors: Kelkar Ajit D. , Sankar J. , Chaphalkar Pramod , Grace C. , Yarmolenko S. N. , Mall Shankar , Vaidya U. K. 
Published: March 2022

Abstract
Woven composites have good properties in mutually orthogonal directions, more balanced properties than unidirectional laminates and have better impact resistance. The use of these composites for primary structural applications in place of conventional laminated composites has been increased considerably in the recent years. They are being manufactured by using new processes such as Resin Infusion (RI) and Resin Transfer Molding (RTM). These new processes are low cost, affordable and suitable for high volume manufacturing environment. One of the popular woven composites is fabricated using S2-Glass and C-50 resin system components by using Resin Infusion (RI) and Resin Transfer Molding (RTM) process. These woven composites are being evaluated for Integral Armor applications. These components are expected to be under fatigue loading. To assess the feasibility of this material manufactured through Resin Infusion (RI) and Resin Transfer Molding (RTM), it is very important to understand the fatigue behavior of these composite materials. In the first phase of the study the panels of this material were fabricated using Resin Infusion (RI) processing. Number of tests were performed to evaluate the basic properties such as modulus, ultimate tensile strength, and Poisson’s ratio of this woven composite. Tension-tension fatigue experiments with R ratio of 0.1 were conducted to generate two important curves to characterize the fatigue behavior of this material system: S-N diagram and stiffness degradation over the entire fatigue life of the specimens. All the fatigue tests were performed at 1 Hz frequency. To study the progressive damage of the textile composites under fatigue loading, one set of specimens was subjected to different number of fatigue cycles starting from 1 cycle to 300,000 cycles and was investigated for failure mechanism using optical microscopy and SEM.