Numerical Evaluation of the Optical Properties of Encapsulated Phase Change Particles for Thermotropic Materials

2015 ◽  
Vol 7 (3) ◽  
Author(s):  
Adam Gladen ◽  
Susan Mantell ◽  
Jane Davidson
Keyword(s):  
Optical Properties ◽  
Phase Change ◽  
Volume Fraction ◽  
Low Cost ◽  
Particle Volume Fraction ◽  
Particle Volume ◽  
Melt Temperature ◽  
The Matrix ◽  
Optical Behavior ◽  
Selection Of

Phase change thermotropic materials have been proposed as a low cost method to provide passive overheat protection for polymer solar thermal absorbers. One challenge to their development is control of the size of the phase change particles dispersed within the matrix. Here we explore encapsulation as a means to resolve this challenge with a focus on the selection of materials, including the encapsulating shell, to achieve desirable optical behavior. Hydroxystearic acid (HSA) particles in a matrix of poly(methyl methacrylate) (PMMA) is down selected from candidate materials based on its optical properties and the melt temperature of the dispersed phase. The optical properties (normal-hemispherical transmittance, reflectance, and absorptance) as a function of the properties of the encapsulation shell and the particle volume fraction are predicted at a wavelength of 589 nm using a Monte Carlo ray tracing model. A range of shell relative refractive indices, from 0.95 to 1, and thicknesses, up to 35 nm, can be employed to achieve greater than 80% transmittance in the clear state and greater than 50% reflectance in the translucent state.

scholarly journals Microstructure-based modeling of the dynamic mechanical properties of SiCp/Al composites

2016 ◽  
Vol 23 (4) ◽  
pp. 363-366
Author(s):  
Mei Ni Yuan ◽  
Yan Qing Yang ◽  
Qiao Juan Gong ◽  
Chao Li ◽  
Xian Zhong Lang
Keyword(s):  
Flow Stress ◽  
Volume Fraction ◽  
Dynamic Properties ◽  
Particle Volume Fraction ◽  
Element Model ◽  
Dynamic Mechanical Properties ◽  
Strengthening Effect ◽  
Particle Volume ◽  
The Matrix ◽  
Angular Particles

AbstractUsing image processing and recognition, a microstructure-based finite element model (FEM) was established to predict the dynamic properties of SiCp/Al composites at different strain rates ranging from 200 to 14,000 s-1. In the microstructure-based FEM, the irregular SiC particles were randomly distributed in the matrix, and its configurations did not change. The results showed that the flow stress of SiCp/Al composites with low particle volume fraction first increases and then decreases with the increasing of strain rate during the adiabatic compression. The reducing flow stress of SiCp/Al composites is caused by the inner damage and the heat softening of composites. The angular particles in SiCp/Al composites provide more strengthening effect than the circle particles when the strain is <0.62, while the circle particles provide more strengthening effect than the angular particles for strain >0.62.

Microstructure and Mechanical Properties of Metal Injection Molded SiCP/ Cu Composites

2012 ◽  
Vol 629 ◽  
pp. 105-109
Author(s):  
Yi Qiang He ◽  
Jian Ming Yang ◽  
Bin Qiao ◽  
Li Chao Feng
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
Particle Volume ◽  
Sic Particles ◽  
The Matrix ◽  
Fraction Increase

SiCP/Cu composite was prepared by metal injection molding process. Microstructure, mechanical properties, fracture surface, and wear resistance of SiCP/Cu composite were investigated in this study. The research results show that SiCP/Cu were sintered sucessfully by the sintering process with hydrogen protection and high temperature of 1050°C. The tensile strength of the composites depends on the fraction and distribution of SiC particles which is resulted from microcracks nucleate in the matrix between SiC particles because of SiC particle aggregation. The tensile strengths of 5vol.%, 10vol.%, and15vol.%SiCP/Cu are 254MPa, 291MPa and 278MPa separately. SiC particles are contribute to enhance the abrasive resitance of the composite when particle volume fraction increase from 10% to 15%.

scholarly journals Numerical analysis of melting of nano-enhanced phase change material in latent heat thermal energy storage system

2014 ◽  
Vol 18 (suppl.2) ◽  
pp. 335-345 ◽  
Author(s):  
Sina Kashani ◽  
Esmail Lakzian ◽  
Kazem Lakzian ◽  
Mohammad Mastiani
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Storage System ◽  
Energy Storage System ◽  
Particle Volume

The heat transfer enhancement in the latent heat thermal energy storage system through dispersion of nanoparticle is reported. The resulting nanoparticle-enhanced phase change materials exhibit enhanced thermal conductivity in comparison to the base material. Calculation is performed for nanoparticle volume fraction from 0 to 0.08. In this study rectangular and cylindrical containers are modeled numerically and the effect of containers dimensions and nano particle volume fraction are studied. It has been found that the rectangular container requires half of the melting time as for the cylindrical container of the same volume and the same heat transfer area and also, higher nano particle volume fraction result in a larger solid fraction. The increase of the heat release rate of the nanoparticle-enhanced phase change materials shows its great potential for diverse thermal energy storage application.

Investigating Load Transfer in Ceramic Reinforcements

2018 ◽  
Author(s):  
Peter Warren ◽  
Ranajay Ghosh ◽  
Sanjida Jahan ◽  
Seetha Raghavan
Keyword(s):  
Load Transfer ◽  
Volume Fraction ◽  
Protective Coatings ◽  
Particle Volume Fraction ◽  
Fuel Efficiency ◽  
Ceramic Composites ◽  
Particle Volume ◽  
The Matrix ◽  
Loading Effects ◽  
Structural Parts

Ceramic composites are critical to advance the performance of engines, reducing weight and enhancing fuel efficiency in their use as structural parts or protective coatings. Understanding load transfer between the reinforcements and matrix materials that constitute these composites hold the key to elucidating their mechanical properties and consequent behavior in operation. In this work, finite element (FE) simulations of loading effects on representative embedded alumina particles in a matrix were investigated and compared with experimental results. Mechanical loading effects on alumina nanoparticle composites can be captured with Photo stimulated luminescent spectroscopy (PSLS), where spectral shifts from the particles are monitored with load. The resulting piezospectroscopic (PS) coefficients are then used to calculate load transfer between the matrix and particle. The results from the simulation and experiments are shown to be in general agreement of increase in load transferred with increasing particle volume fraction due to contact stresses that are dominant at these higher volume fractions. Results from this work present a combination of analytical and experimental insight into the effect of particle volume fraction on load transfer in ceramic composites that can serve to determine properties and eventually optimize various parameters such as particle shape, size and dispersion that govern the design of these composites prior to manufacture and testing.

Parametric Study for the Phase-Change Process of Liquid Flow With Microencapsulated PCM Particles in Microchannels

2007 ◽  
Author(s):  
Yingli Hao ◽  
Jinli Lu
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Wall Temperature ◽  
Change Process ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Suspension Flow ◽  
Particle Volume ◽  
Constant Wall Temperature ◽  
Phase Change Process

The phase-change process of phase-change material (PCM) is the key for the microencapsulated phase-change material (MCPCM) particle suspension flow to enhance the heat transfer, enlarge the capability of thermal energy transportation and employ in the engineering application. In the present paper, the parametric study for the phase-change process of the MCPCM suspension flow in a heated microchannel is carried out using the model and numerical technique developed in previous works. The effects of particle volume fraction, Reynolds number, and wall heat flux on the phase-change process have been numerically analyzed. It is found that the benefits of enhancing heat transfer and reducing wall temperature by employing the MCPCM particle are limited to the melting region. There exists a constant wall temperature region in the melting region under the certain condition. The trend of influence of particle volume fraction, Reynolds number, and wall heat flux on starting location, length, wall temperature, and average heat transfer coefficient in the constant wall temperature region is revealed. The numerical simulation may guide the optimal condition of design and operation to utilize the MCPCM suspension flow not only for enhancing the convection heat transfer and enlarging the thermal energy transportation capability, but also for controlling the micro-device temperature uniform.

Computer Simulation Model for Multi-Size Spherical Particles Reinforced Composite Materials

2012 ◽  
Vol 508 ◽  
pp. 361-364 ◽  
Author(s):  
Zhuo Chen ◽  
Zhi Xiong Huang ◽  
Rong Yang Dou ◽  
Jing Dai ◽  
Min Xian Shi ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Composite Materials ◽  
Simulation Model ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Spherical Particles ◽  
Computer Simulation Model ◽  
Particle Volume ◽  
Reinforced Composite ◽  
The Matrix

In this Research a Method for Computer Simulation Model of Composite Materials, which Are Reinforced by Multi-Size Particles, Is Introduced. All Particles Are Embedded in the Matrix Randomly. Composite of Different Particle Volume Fraction Were Simulated and Visualized. Statistic Results Shows that the Particles Disperse Distribution Are Uniform which Could Be Used in the Further Study of Composite.

The effect of high TiC particle content on the tensile cracking and corrosion behavior of Al–5Cu matrix composites

2019 ◽  
Vol 54 (13) ◽  
pp. 1681-1690 ◽  
Author(s):  
Burak Dikici ◽  
Fevzi Bedir ◽  
Mehmet Gavgali
Keyword(s):  
Corrosion Behavior ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Tensile Tests ◽  
Matrix Composites ◽  
Particle Volume ◽  
The Matrix ◽  
Tic Particle ◽  
Mechanical Properties And Corrosion ◽  
Tic Particulates

The high-TiC particle volume fraction on the mechanical properties and corrosion behavior of the A–5Cu matrix composites were investigated with porosity, hardness, tensile tests, and polarization measurements. The composites reinforced with 18, 27, and 50 vol% TiC particulates were produced successfully by using hot-pressing technique under Ar atmosphere and characterized by scanning electron microscope, electron dispersive spectroscope, and X-ray diffraction. The corrosion susceptibilities of the composites were compared with potentiodynamic scanning technique. It was found that the hardness of the composites increases while the fracture strength decreases with increasing TiC reinforcement content in the matrix. The corrosion susceptibilities of 18 and 27 vol% TiC-reinforced composites are almost the same; the corrosion rate of 50 vol% TiC-reinforced composite was approximately 10 times higher than the composites reinforced with 18 and 27 vol% TiC particles in the 3.5% NaCl. In addition, some preferential corrosion attacks were detected at TiC/matrix interfaces and in TiC clusters during the corrosion process of the composites. Therefore, the porosity content in the composites was almost the same level.

Concurrent design of nanofluid for x-abilities using MADM approach

2016 ◽  
Vol 23 (5) ◽  
pp. 1286-1311 ◽  
Author(s):  
Jyoti Prakash ◽  
Vishnu P. Agrawal
Keyword(s):  
Sensitivity Analysis ◽  
Heat Exchanger ◽  
Thermophysical Properties ◽  
Design Methodology ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Concurrent Design ◽  
Particle Volume ◽  
Content Type ◽  
Selection Of

Purpose – Multiple attribute decision making (MADM) is a conceptual agenda used for evaluation and selection of optimal nanofluid to assure best performance of heat exchanger. Most of the studies focus on nanofluids focus on individual ability at one time. Relatively, not even a single study is available for selection of nanofluid for heat exchanger using concurrent design and MADM approach. The purpose of this paper is to propose a concurrent design methodology using MADM approach to assist improved design of heat exchanger concurrently for all the x-abilities in an integrated manner. Design/methodology/approach – A combined methodology of applying MADM approach using concurrent design for x-abilities is called CE-MADM approach. Implementation of nanofluid to improve thermal performance of heat exchanger entails thorough evaluation of nanofluids in various x-abilities (performance, maintenance, thermophysical properties and modelisation) to make exhaustive management decision. Sensitivity analysis is also proposed to study the behaviour of height of variation of density, heat capacity, thermal expansion and thermal conductivity with varying particle volume fraction and variation of relative closeness of available alternates from ideally best possible solution. Findings – MADM approach considering various x-abilities concurrently provide an approach for relative ranking of available nanofluids for optimum performance. Fishbone diagrams of all x-abilities are constructed to identify all the attributes and converge large number of attributes into single numerical index that are concurrently responsible for the cause thus saving time for easy evaluation, comparison and ranking by decision makers. Sensitivity analysis to demonstration height of variation of pertinent attributes with varying particle volume fraction. A MATLAB programming is established to execute calculations involved in the procedure. Originality/value – This paper comprises a predictable and effective mathematical approach to improve design of heat exchanger with nanofluid bearing in mind all the required x-abilities concurrently. This combined approach of CE-MADM is never applied before in the field of nanofluid to predict best possible results in feasible conditions considering all the x-abilities. Sensitivity analysis is also presented from the assumed mathematical equations of thermophysical properties.

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