bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Study of Thermal Energy Storage System
Authors: Yang Bing-Chwen , Huang Shr-Hau , Lin Hsiang-Hui 
Published: November 2021

Abstract
In this paper, the feasibility of phase change material that used for thermal energy storage in the range of 400 ∼ 600°C in the form of latent heat is examined for nine different salts and eutectic salts. The Differential Scanning Calorimeter (DSC) was used to perform the quantitative measurement of the phase change temperature (Tm) and latent heat (ΔH). The thermal properties of NaCl-CaCl2 at repeated heating and cooling cycles were studied with a heating chamber. The quality observation for this phase change material was also performed with this heating chamber to understand its physical phenomena during heating and cooling process. It is found that NaCl-CaCl2 is a good candidate of thermal energy storage material for its stable properties, low cost, and no toxic. Finally, the thermal storage unit with NaCl-CaCl2 as thermal energy storage material was tested to study and evaluate its performance as the application in the waste heat recovery system.
Dynamic Behavior of a Directly Combined Binary Turbine System Using a Mixture (R134a/R123)
Authors: Tanzawa Yoshiaki , Amano Yoshiharu , Hashizume Takumi , Usui Akira 
Published: November 2021

Abstract
Our previous binary turbine system, which employs steam as the primary working fluid, used R11 as the secondary working fluid because R11 has good characteristics as a working fluid in power plants. However, substitute LBMs (Low Boiling temperature Mediums) are being developed because of the ozone layer depletion by CFCs. We investigated the system using R123 in the next stage. Because R123 is also controlled, in the previous paper, modeling of the dynamics of a directly combined binary turbine system using a mixture of R134a and R123 are described. In this paper, the steady state characteristics and dynamic behavior of the system using a mixture of R134a and R123 are investigated taking into account the mole fraction of the mixture. In addition to the investigation using the experimental system, the following are clarified using our model: In the steady-state characteristics, there are remarkable differences in pressure based on the thermodynamic properties and in the load allotment of the two turbines. However, in the dynamic characteristics, the effect of the mole fraction could hardly be observed on the response characteristics of the rotating components to the load change.
Study of a Fuel Cell Cogeneration System Applied to a Brazilian Tertiary Sector
Authors: Silveira Jose Luz , Leal Elisângela Martins 
Published: November 2021

Abstract
In this paper, a methodology for the study of a molten carbonate fuel cell cogeneration system and applied to a computer center building is developed. This system permits the recovery of waste heat, available between 600°C and 700°C, which can be used to the production of steam, hot and cold water, hot and cold air, depending on the recuperation equipment associated. Initially, some technical information about the most diffusing types of the fuel cell demonstration in the world are presented. In conclusion, the fuel cell cogeneration system may have an excellent opportunity to strengthen the decentralized energy production in the Brazilian tertiary sector.
Handling of Collimated Irradiation on a Plane-Parallel Participating Medium
Authors: Proulx Christian , Rousse Daniel R. , Vaillon Rodolphe , Sacadura Jean-François 
Published: November 2021

Abstract
This article presents selected results of a study comparing two procedures for the treatment of collimated irradiation impinging on one boundary of a participating one-dimensional plane-parallel medium. These procedures are implemented in a CVFEM used to calculate the radiative heat flux and source. Both isotropically and anisotropically scattering media are considered. The results presented show that both procedures provide results in good agreement with those obtained using a Monte Carlo method, when the collimated beam impinges normally.
A PIV Methodology for High-Resolution Measurement of Flow Statistics
Authors: Cummings Eric B. , Schefer Robert W. , Chung Jacob N. 
Published: November 2021

Abstract
Particle-image velocimetry (PIV) is a flow-diagnostic technique that provides velocity fields from a comparison of images of particulate-laden flow. We have developed a PIV processing methodology that extracts measurements of the particle-displacement probability density function (PDF) from a flow video or ensemble of flow-image pairs. Single-pixel measurement of mean velocity can be obtained from an ensemble of O(103) images. Measurements of higher-order moments of the velocity PDF require spatial averaging (i.e., lower spatial resolution), larger ensembles of images, or a combination of the two. We present single-pixel-resolution PIV measurements of a steady microflow and high-resolution measurements of the velocity PDF of a stationary turbulent flow. This methodology has applications in quantifying velocity statistics in other stochastic flows, e.g., bulk and near-wall boiling.
The Effect of Radiation on Turbulent Convective Heat Transfer Over an Ablating Solid
Authors: Akyuzlu K. M. , Antoniou A. , Kagoo R. 
Published: November 2021

Abstract
A numerical study is conducted to investigate the effect of thermal radiation on turbulent flow (upstream of the flame front) inside a subscale planar hybrid rocket motor. The physical model adopted for the study is based on an unsteady two-domain (solid fuel and gaseous oxidizer) concept where both domains are assumed to be two-dimensional. Furthermore, the oxidizer gas flow is assumed to be incompressible and turbulent with boundary layer approximations. The radiative heat transfer is incorporated to the energy equation for the oxidizer using the Rosseland diffusion approximation. Fuel is assumed to be a nontransparent isotropic solid. The two domains are coupled through an energy balance at the interface that includes heat transfer due to radiation, conduction, and ablation. The solution to the governing differential equations of the present model is obtained by first linearizing the equations using Newton linearization method, discretizing them by a fully implicit finite-difference technique, and then solving the resulting set of algebraic equations by a block tridiagonal matrix solver. Finally, the proposed mathematical model is used in a parametric study to determine the effect of various operational parameters, such as flame temperature and oxidizer mass flow rate, on heat transfer from the solid fuel. Results indicate the significance of radiation on turbulent convective heat transfer over an ablating solid.
Two Fiber Optical Fiber Thermometry
Authors: Jones Matthew R. , Farmer Jeffery T. , Breeding Shawn P. 
Published: November 2021

Abstract
An optical fiber thermometer consists of an optical fiber whose sensing tip is given a metallic coating. The sensing tip of the fiber forms an isothermal cavity, and the emission from this cavity is approximately equal to the emission from a blackbody. Temperature readings are obtained by measuring the spectral radiative flux at the end of the fiber at two wavelengths. The ratio of these measurements is used to infer the temperature at the sensing tip. However, readings from optical fiber thermometers are corrupted by emission from the fiber when extended portions of the probe are exposed to elevated temperatures. This paper describes several ways in which the reading from a second fiber can be used to correct the corrupted temperature measurements. It is shown that two of the correction methods result in significant reductions in the systematic errors. However, these methods are sensitive to random errors, so it is preferable to use a single fiber OFT if the uncertainties in the measurements are large.
Heat Transfer Implications in the First MEMS Fabricated Thermal Transpiration-Driven Vacuum Pump for Gases
Authors: Vargo Stephen E. , Green Amanda A. , Muntz E. P. 
Published: November 2021

Abstract
The success of NASA’s future space missions and the development of portable, commercial instrument packages will depend greatly on miniaturized components enabled by the use of microelectromechanical systems (MEMS). Both of these application markets for miniaturized instruments are governed by the use of MEMS components that satisfy stringent power, mass, volume, contamination and integration requirements. An attractive MEMS vacuum pump for instruments requiring vacuum conditions is the Knudsen Compressor, which operates based on the rarefied gas dynamics phenomenon of thermal transpiration. Thermal transpiration describes the regime where gas flows can be induced in a system by maintaining temperature differences across porous materials under rarefied conditions. This pumping mechanism provides two overwhelmingly attractive features as a miniature vacuum pump — no moving parts and no working fluids or lubricants. Due to favorable power, volume and mass estimates a Knudsen Compressor fabricated using MEMS fabrication techniques (lithography, deep reactive ion etching) and new materials (silicon, aerogel) has been completed. The experimental testing of this MEMS Knudsen Compressor device’s thermal and pumping performance are outlined in this manuscript. Good agreement between experiments and numerical predictions using a transitional flow analysis have also been obtained although simple simulations based on the aerogel’s structure are difficult to perform.
Applications of Artificial Neural Network Analysis in Thermal Systems
Authors: Mahajan R. L. , Yang K. T. 
Published: November 2021

Abstract
Artificial neural networks (ANNs) are good at approximating complex and non-linear data. In addition, they have excellent predictive capabilities and can be configured to be self-adaptive. As a result of these characteristics, the potential applications of ANNs are many and in diverse fields. These range from predicting the output of a manufacturing process through differentiating between handwritten letters to predicting the winner of a horse race. In this paper, we focus on applications of artificial neural networks to thermal systems including chemical vapor deposition, thermal management and heat exchangers.
Coalescence of Dual Bubbles on Micro Heaters
Authors: Chen Tailian , Chung J. N. 
Published: November 2021

Abstract
This experiment is based on a heating surface consisting of micro heaters where the temperature of each heater can be individually controlled by an electronic feedback loop similar to those used in hotwire anemometry. The power consumed by the heaters throughout the cycle of individual bubble growth, coalescence and departure was measured at high frequencies, thus the heat flux and its variation were obtained. At the same time, visualization of bubbles’ behaviour by a fast CCD camera has been performed to gather more information. By combining the heat flux data closely with the visualization result, we have found that the single bubble’ heat flux variation correlates with the separate stages of its life cycle: nucleation, growth, detachment and departure. By careful timing and control of two individual heaters, we were able to grow two individual bubbles side-by-side. The coalescence of these two bubbles would take place when they grow to a certain size that allows them to touch each other. We have recorded two major heat flux spikes for a typical cycle. The first one corresponds to the nucleation of bubbles, the second one is for the coalescence of the two bubbles. We found that the heat flux variation is closely related to the bubble dynamics and bubble-bubble interaction.
Design of Liquid Cooled Coldplate for the Inverter of the Hybrid Electric Vehicle
Authors: Jih C. Edward , Chen K. , Abraham T. , Siddapureddy V. , Poulson R. , Sankaran V. A. 
Published: November 2021

Abstract
As the performance of the advanced electric systems increases, the packaging densities and power requirements will also increase. The reliability of these components will depend on the ability of the packaging system to transport heat away from the device. In this paper, a liquid-cooled coldplate for the inverter of hybrid electric vehicle was designed by using Computational Fluid Dynamics (CFD) technique. The main features of inverter packaging include power module, capacitors, busbar, gate driver, gate power supply, coldplate, sensors, & controllers. How to effectively dissipate the heat from power module to the coldplate is the focus of this study. The 3-phase full bridge power module consists of 12 IGBTs and 12 diodes. The silicon dies of IGBT or diode were soldered to the direct-bonded ceramic (DBC) A1N substrate, and to the copper base plate. Then the whole module was mounted mechanically onto an aluminum coldplate using thermal grease at the interface. The maximum allowable die junction temperature is 125°C. The commercial CFD code, FLUENT, was used here to study the flow field and heat transfer of the coldplate. In order to have confidence in the CFD prediction, the temperature distribution of an inverter assembly was obtained from FLUENT and then verified with the measurement from an infrared camera. Several design options on the coldplate, i.e., diameter & height of fins and shape & pattern of fin arrays, were examined. The effects of coolant flow rate and coolant type on the performance of coldplate were also studied. The overall thermal resistance and pressure drop of the coldplate were used to compare the efficiency of a series of coldplate design. Based on the CFD results, the effect of coldplate pin fins design on the thermal resistance is small. However, the pressure drop of the coldplate is quite sensitive to the design of pin fins. It is also noted that the fin height of coldplate can be reduced by 10% without degrading the performance of coldplate.
Aggregate Intensification of Natural Convection Between Air and a Vertical Parallel-Plate Channel by Inserting an Auxiliary Plate at the Mouth and Appending Colinear Insulated Plates at the Exit
Authors: Andreozzi Assunta , Manca Oronzio , Campo Antonio 
Published: November 2021

Abstract
This paper addresses the examination of heat transfer in parallel-plate channels using a combination of two passive schemes: (1) the insertion of an auxiliary plate at the mouth and (2) the appendage of colinear insulated plates at the exit. The investigation is made by numerically solving the full elliptic Navier-Stokes and energy equation in a I-type computational domain. The channel is symmetrically heated by uniform heat flux. The working fluid is air. The results are reported in terms of induced mass flow rate and maximum wall temperatures. Further, the local Nusselt number, the mean Nusselt number and pressure profiles are presented. The analyzed Grashof numbers based on the heated plate height are 103 and 106.
Ceramic Miniature Heat Pipes and Liquid Charging Methods
Authors: Gao Mingcong , Cao Yiding , Jones W. Kinzy , Zampino Marc A. 
Published: November 2021

Abstract
Three working-liquid charging methods for miniature heat pipes are introduced, and their advantages and disadvantages are described. Using these methods, two types of ceramic heat pipes were charged and tested. The ceramic heat pipes were made of alumina and have overall dimensions of 89 mm × 12 mm × 2.9 mm and a designed vapor space of 82.5 mm × 4.1 mm × 1.27 mm. Axial micro capillary grooves were provided on the top and bottom or sidewalk inside the heat pipes as wick structures. Water was used as working liquid. More than 20 Watts of heat input was achieved on a 5 mm × 5 mm heating surface. The corresponding heat flux was 80 W/cm2.
Active Thermal Control of an Ion-Drag Pump Assisted Micro Heat Pipe
Authors: Yu Zhiquan , Pohlman Nicholas A. , Hallinan Kevin P. , Kashani Reza 
Published: November 2021

Abstract
An ion-drag pump is utilized to enhance the heat transport capacity of micro heat pipes. An analytical model is developed to estimate the maximum heat transport capacity as a function of the applied electric field. The model predicts that the application of an electric field causes a four fold increase in heat transport capacity. A transient analytical model was developed to permit variation of the electric field with applied thermal load. A proportional-integral-derivative controller was used to simulate active temperature control. The feasibility of achieving active temperature control was demonstrated experimentally.
Investigation of a Stiff-Integrator Scheme for High-Speed Reacting Flows
Authors: Woolley Lance D. , Schwer Douglas A. , Daines Russell L. 
Published: November 2021

Abstract
Improvements in the modeling of high-speed reacting propulsion flowfields are sought through the coupling of a stiff integrator to determine chemical reaction rates with a multidimensional CFD code. Detailed chemical kinetics models usually have significantly shorter reaction time scales than the fluid time scales, resulting in stiff governing equations and robustness issues. The present work investigates the application of a stiff ordinary differential equation solver, coupled to a diagonalized alternating-direction implicit scheme to decouple the governing time scales. This coupled ODE-ADI split-operator technique is applied to two high-speed reacting flows using hydrogen/air chemistry. The results from the stiff integrator method are compared to the traditional coupled approach utilizing 8- and 18-step kinetics models. Time-step choice, robustness, and comparison of results between the different solution methods are discussed, along with CPU times.
Modeling a Catalytic Combustor for a Steam Reformer in a Methanol Fuel Cell Vehicle
Authors: Sundaresan Meena , Ramaswamy Sitaram , Moore Robert M. 
Published: November 2021

Abstract
Using a fuel other than pure hydrogen in a fuel cell vehicle (FCV) employing a Proton Exchange Membrane (PEM) fuel cell stack typically requires an on-board fuel processor to provide hydrogen-rich fuel to the stack. In the case of methanol as the source fuel, the reformation process typically occurs in a fuel processor that combines a steam reformer plus a catalytic burner (to provide the necessary energy for the endothermic steam reforming reactions to occur). This paper will discuss a model for the catalytic burner in a methanol fuel processor for an Indirect Methanol FCV. The model uses MATLAB/Simulink software and the simulation provides results for both energy efficiency and pollutant formation.
Improving the Performance of a Vibration Neutraliser by Controlling Its Stiffness and Damping
Authors: Brennan M. J. , Kidner M. R. F. 
Published: November 2021

Abstract
This paper is concerned with improving the performance of a vibration neutraliser (absorber) by making it adaptive. To achieve this, the stiffness and damping of the device has to be controlled so that the impedance of the neutraliser is optimised at its operational frequency. The results of an experimental study are presented where real-time control of such a device is demonstrated. The stiffness is adjusted by changing the geometry, and damping is controlled with a velocity feedback system. Both these actions are achieved using a fuzzy logic controller.
Ultra-Pure Viscoelastic Damping Polymers and Associated Low Outgassing Materials
Authors: McCutcheon Jeff W. 
Published: November 2021

Abstract
The key to successful multifunctional materials applications for vibration, shock and acoustic control is often the proper selection of materials, geometric design and optimum application. Much work has been done in the areas of geometric designs and optimum application of the multi-functional materials. The next step is improvements in the passive damping materials themselves.
The improvement in the passive materials in the past has often focused on the areas of improved damping performance (loss factor, storage modulus), material performance (acrylics, silicones, etc.) and enhanced features (thermally conductive, electrically conductive, etc). One of the newest requirements for passive damping polymers is in the area of ultra-pure viscoelastic damping polymers. This new generation of materials is finding growing use because the sensitive environment where the passive material is used require a material that will not negatively impact the components in that environment. This new generation of passive materials needs to be ultra-pure with respect to organic material outgassing, anions, catalysts and siloxanes.
In addition to the viscoelastic damping polymer requirements for high purity, the associated polymeric materials (epoxies, laminating adhesives and tapes) used in the same environment must also be of a similar low outgassing, ultra-pure, ultra-clean, electronics grade or clean room performance designation. If this is not done, the environment could become contaminated and negate a portion of the benefit of using the clean damping material. This also requires an understanding of the test method used to determine each product’s cleanliness performance, as all test methods are not equal and can give significantly different test results. An example is comparing a polymer sample tested for organic outgassing and using a static headspace gas chromatography/mass spectroscopy (GC/MS) and a dynamic headspace GC/MS.
A Study on Diesel Fuel Drop Size Distribution
Authors: Jawad Badih A. 
Published: November 2021

Abstract
A pulsed Malvern drop-size analyzer, based on Fraunhofer diffraction, was utilized to determmine droplet size size ranges of diesel fuels under different conditions of injection. the effects of fuel properties, design and operating parameters on the formation of diesal spray are discussed. In these studies, the spray is formed by injecting a calibrated amount of fuel into air with the frequency of the intermittent behavior controlled by the speed of the fuel pump. In this study, an injection cycle was tailored so that it was divided into several increments which were injected sequentially. A two mm diammeter collimated beam illuminated a cylindrical volume perpendicular to the axis of the fuel spray, and its attenuation was recorded and stored on the oscilloscope. With the optical measurement being synchronized to the needle lift of the injector, the output of the needle lift transducer and the optical signal was recorded simultaneously. Thus, the arrival and the duration of the spray at various positions along its axis were measured.
The droplet size distributions were obtained directly as penetration measurements were made. However, by applying a delay time through the synchronization feature of the sizer, information about droplet size evolution within the same spray was possible. Distribution widths are plotted as a function of time for different chamber pressures, injection pressures, different positions, and different fuels. Coagulation seems to be a dominant phenomenon in these studies.