Fundamental Study on Laser Interactions With Nanoparticles-Reinforced Metals—Part I: Effect of Nanoparticles on Optical Reflectivity, Specific Heat, and Thermal Conductivity

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Chao Ma ◽  
Jingzhou Zhao ◽  
Chezheng Cao ◽  
Ting-Chiang Lin ◽  
Xiaochun Li
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Specific Heat ◽  
Thermophysical Properties ◽  
Room Temperature ◽  
Al2o3 Nanoparticles ◽  
Fundamental Study ◽  
Optical Reflectivity ◽  
Theoretical Results ◽  
Laser Interactions

It is of tremendous interest to apply laser to process nanoparticles-reinforced metals for widespread applications. However, little fundamental understanding has been obtained on the underlining physics of laser interactions with nanoparticles-reinforced metals. In this work, fundamental study was carried out to understand the effects of nanoparticles on the optical and thermophysical properties of the base metal, the corresponding heat transfer and melt pool flow processes, and the consequent surface property in laser melting. Part I presents both experimental and theoretical results on the effects of nanoparticles on the optical reflectivity, specific heat, and thermal conductivity. Electrocodeposition was used to produce nickel samples with nanoparticles. Using a power meter, the reflectivity of Ni/Al2O3 (1.8 vol. %) was measured to be 65.8% while pure Ni was at 67.4%, indicating that the Al2O3 nanoparticles did not change the reflectivity substantially. Differential scanning calorimetry was used to determine the heat capacity of the nanocomposites. The specific heat capacities of the Ni/Al2O3 (4.4 vol. %) and Ni/SiC (3.6 vol. %) at room temperature were 0.424 ± 0.013 J/g K and 0.423 ± 0.014 J/g K, respectively, close to that of pure Ni, 0.424 ± 0.008 J/g K. An experimental setup was developed to measure thermal conductivity based on the laser flash method. The thermal conductivities of these Ni/Al2O3 and Ni/SiC nanocomposites at room temperature were 84.1 ± 3.4 W/m K and 87.3 ± 3.4 W/m K, respectively, less than that of pure Ni, 91.7 ± 2.8 W/m K. Theoretical models based on the effective medium approximation theory were also used to predict the heat capacity and thermal conductivity of the nanoparticles-reinforced nickel. The theoretical results match well with the measurements. The knowledge of the optical and thermophysical properties of nanoparticles-reinforced metals would provide valuable insights to understand and control laser processing of metal matrix nanocomposites.

Thermophysical Properties of Germanium for Thermal Analysis of Growth from the Melt

1981 ◽  
Vol 9 ◽  
Author(s):  
Roger K. Crouch ◽  
A. L. Fripp ◽  
W. J. Debnam ◽  
R. E. Taylor ◽  
H. Groot
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Thermophysical Properties ◽  
Room Temperature ◽  
Bridgman Method ◽  
The Other ◽  
Temperature Range ◽  
Diffusivity Measurements

ABSTRACTThe thermal diffusivity of Ge has been measured over a temperature range from 300° C to 1010° C which includes values for the melt. Specific heat has been measured from room temperature to 727° C. Thermal conductivity has been calculated over the same temperature range as the diffusivity measurements. These data are reported along with the best values from the literature for the other parameters which are required to calculate the temperature and convective fields for the growth of germanium by the Bridgman method. These parameters include the specific heat, the viscosity, the emissivity, and the density as a function of temperature.

Study and Analysis of Metal Coolant Thermophysical Properties

2012 ◽  
Vol 184-185 ◽  
pp. 1226-1231
Author(s):  
Meng Ying Liu ◽  
Tao Zhou ◽  
Wen Zhong Zou ◽  
Zi Wei Su
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermophysical Properties ◽  
Kinematic Viscosity ◽  
Fusion Reactor ◽  
Small Difference ◽  
Heat Transfer Capacity ◽  
Metal Coolant

The article chooses Na, LiPb and LBE three kinds of metal coolant, and makes a comparative analysis of the thermophysical properties of Na, LiPb and LBE when they are at liquid state. The results show that Na has the lowest density and the largest thermal conductivity and specific heat capacity. There is a small difference between LBE and LiPb in terms of density, thermal conductivity and specific heat capacity. LiPb has the largest kinematic viscosity. The thermal conductivity of Na decreases as temperature rises, which is opposite of LBE and LiPb. The kinematic viscosity of LiPb increases as temperature rises. Considering thermal conductivity and specific heat capacity, LBE and LiPb are not the best coolant. However, their high densities can economize equipments and materials at the same time. When it flows, LiPb’s heat transfer capacity gets larger as temperature rises, this character can not be ignored in fusion reactor.

scholarly journals Thermophysical Properties of Larch Bark Composite Panels

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2287
Author(s):  
Lubos Kristak ◽  
Ivan Ruziak ◽  
Eugenia Mariana Tudor ◽  
Marius Cătălin Barbu ◽  
Günther Kain ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermophysical Properties ◽  
Urea Formaldehyde ◽  
Raw Material ◽  
Particle Orientation ◽  
Thermal Resistivity

The effects of using 100% larch bark (Larix decidua Mill) as a raw material for composite boards on the thermophysical properties of this innovative material were investigated in this study. Panels made of larch bark with 4–11 mm and 10–30 mm particle size, with ground bark oriented parallel and perpendicular to the panel’s plane at densities varying from 350 to 700 kg/m3 and bonded with urea-formaldehyde adhesive were analyzed for thermal conductivity, thermal resistivity and specific heat capacity. It was determined that there was a highly significant influence of bulk density on the thermal conductivity of all the panels. With an increase in the particle size, both parallel and perpendicular to the panel´s plane direction, the thermal conductivity also increased. The decrease of thermal diffusivity was a consequence of the increasing particle size, mostly in the parallel orientation of the bark particles due to the different pore structures. The specific heat capacity is not statistically significantly dependent on the density, particle size, glue amount and particle orientation.

scholarly journals Study on Thermophysical Properties of a Lead–Bismuth-Based Graphene Nanofluid

2021 ◽  
Vol 9 ◽  
Author(s):  
Tao Yang ◽  
Pengcheng Zhao ◽  
Qiong Li ◽  
Yanan Zhao ◽  
Tao Yu
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermophysical Properties ◽  
Prediction Models ◽  
Reactor Core ◽  
Engineering Application ◽  
Nanoparticle Suspension ◽  
Graphene Nanoparticles

Incorporating graphene nanoparticles with high thermal conductivity into a lead-based coolant can significantly increase its thermal conductivity and specific heat capacity, thereby increasing the core power density of lead–bismuth cooled reactors, reducing the amount of coolant required, and ultimately realizing a miniaturized and lightweight reactor design. The purpose of the design is of great significance to the engineering application of lead–bismuth stacks in remote areas and open seas. In this study, the thermophysical properties of metal-based graphene nanofluids are analyzed by comparing and analyzing prediction models established for the thermal conductivity, viscosity, and specific heat capacity. The strengthening mechanism of nanofluids is summarized, and a series of suitable calculation formulae for the thermophysical properties of lead–bismuth-based graphene nanofluids is proposed. The research results show that incorporating graphene nanoparticles into a lead–bismuth-based coolant can significantly improve its thermal conductivity and specific heat capacity. When the nanoparticle suspension is relatively stable, the thermal conductivity, specific heat capacity, and viscosity increase significantly with the concentration of graphene nanoparticles. When the concentration reaches 20%, the thermal conductivity and specific heat capacity of the nanofluid are enhanced by approximately 80 and 20%, respectively, whereas the viscosity is also increased by approximately 100%. Therefore, it is important to appropriately select the parameters for the addition of nanoparticles to maximize the effect of lead–bismuth-based graphene nanofluids on the heat transfer performance of the reactor core.

scholarly journals ANALYSIS OF THE THERMOPHYSICAL PROPERTIES AND INFLUENCING FACTORS OF VARIOUS ROCK TYPES FROM THE GUIZHOU PROVINCE

2018 ◽  
Vol 53 ◽  
pp. 03059 ◽  
Author(s):  
Song Xiaoqing ◽  
Jiang Ming ◽  
Xiong Peiwen
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Diffusion Coefficient ◽  
Specific Heat ◽  
Thermal Diffusion ◽  
Specific Heat Capacity ◽  
Thermophysical Properties ◽  
Guizhou Province ◽  
Thermal Diffusion Coefficient ◽  
Rock Types

A series of analyses have been carried out on a number of rock types from the Guizhou Province to investigate their thermophysical properties. A total of 433 samples from 14 types of rock were collected, tested and analyzed. It was found that in this province, the average thermal conductivity of the samples ranged between 1.516±0.264 and 5.066±0.521 W/(m·K), the average specific heat capacity varied from 0.272±0.042 to 0.603±0.096 kJ/(kg·°C), and the average thermal diffusion coefficients were from 0.752±0.331 to 2.854±0.368 MJ/(m3·K). The older rocks always had higher thermal conductivity and thermal diffusion. Thermal conductivity and thermal diffusion of rocks are positively correlated with the mineral content of high thermal conductivity species, but the situation for the specific heat capacity is the opposite. With increasing mineral particle size, the thermal conductivity and thermal diffusion coefficient also increase, but the relationship with specific heat capacity is not obvious. The thermal conductivity and thermal diffusion coefficient of rocks increases under water saturated conditions compared to dry conditions, but the specific heat capacity decreases.

Enhanced Thermal Performance of Ionic Liquid-Al2O3 Nanofluid as Heat Transfer Fluid for Solar Collector

2013 ◽  
Author(s):  
Titan C. Paul ◽  
A. K. M. M. Morshed ◽  
Elise B. Fox ◽  
Ann E. Visser ◽  
Nicholas J. Bridges ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Ionic Liquids ◽  
Thermal Performance ◽  
Thermophysical Properties ◽  
Heat Transfer Fluid ◽  
Al2o3 Nanoparticles ◽  
Diphenyl Oxide ◽  
Volume Percentage

Next generation Concentrating Solar Power (CSP) system requires high operating temperature and high heat storage capacity heat transfer fluid (HTF), which can significantly increase the overall system efficiency for power generation. In the last decade several research going on the efficacy of ionic liquids (ILs) as a HTF in CSP system. ILs possesses superior thermophysical properties compare to currently using HTF such as Therminol VP-1 (mixture of biphenyl and diphenyl oxide) and thermal oil. However, advanced thermophysical properties of ILs can be achieved by dispersing small volume percentage of nanoparticles forming nanofluids, which is called Nanoparticle Enhanced Ionic Liquids (NEILs). In the present study NEILs were prepared by dispersing 0.5% Al2O3 nanoparticles (spherical and whiskers) in N-butyl-N, N, N-trimetylammonium bis(trifluormethylsulfonyl)imide ([N4111][NTf2]) IL. Viscosity, heat capacity and thermal conductivity of NEILs were measured experimentally and compared with the existing theoretical models for liquid–solid suspensions. Additional, the convective heat transfer experiment was performed to investigate thermal performance. The thermal conductivity of NEILs enhanced by ∼5%, heat capacity enhanced by ∼20% compared to the base IL, which also gives 15% enhancement in heat transfer performance.

Thermophysical Properties of Steam–Air Under High Temperature and High Pressure

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Zhengbin Wu ◽  
Shu Jiang ◽  
Lei Wang ◽  
Yiguo Zhang
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
High Pressure ◽  
High Temperature ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Heavy Oil ◽  
Thermophysical Properties ◽  
Steam Injection ◽  
Steam System

Abstract Air-assisted steam injection is a new technique for heavy oil reservoir exploitation. This paper focused on the thermophysical properties of the air/steam system, such as density, viscosity, specific heat capacity, enthalpy, and thermal conductivity coefficient, and these have been calculated using the Redlich–Kwong equation of state (RK EOS). The viscosity of the air/steam system under high temperature and high pressure was calculated with the corresponding state principle and rectified with the Dean–Stiel residual viscosity method. The results showed that compared with the saturated steam of the same mass, the viscosity, specific heat capacity, thermal conductivity, and enthalpy of the air/steam mixture decreased, while the specific volume increased, which indicated that the addition of air to steam weakened the thermal effect of the steam and makes use of the heat insulation and thermal expansion of air. This study can provide guidance for parameter design of air-assisted steam injection for heavy oil recovery.

Effect of Mechanical Compression on Thermal Characteristics of Tissue-Mimicking Material

2015 ◽  
Author(s):  
Binh T. Hoang ◽  
Austin Roth ◽  
Adriana Druma ◽  
Mallika Keralapura ◽  
Sang-Joon John Lee
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Flux ◽  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Room Temperature ◽  
Mechanical Compression ◽  
Tissue Mimicking Material

Tissue-mimicking materials (TMM) are often used as surrogates for human tissue when developing prospective treatments such as thermal ablation of tumors. Localized heating or ablation may be applied by methods including high-intensity focused ultrasound (HIFU), radio frequency (RF), microwave, and laser treatment. In such methods, confining the heated region to a narrow target is an important concern for minimizing collateral damage to surrounding healthy tissue. Mechanical compression can potentially assist in confining heat near a target region by constricting microvascular blood flow. However, characterization of the effects of compression on thermal properties of the tissue itself (apart from microvasculature) is needed for accurate modeling of heat transfer. Accordingly this study presents a method and material characterization results that quantify the extent to which mechanical compression alters thermal conductivity, specific heat capacity, and thermal diffusivity of a polyacrylamide-based TMM. Cylindrical test specimens were cast from polyacrylamide material with diameter of 50 mm and height of 45 mm. Compression was applied using custom apparatus for applying prescribed uniaxial displacement, with a modular configuration for testing under ambient temperature as well as on a hot plate. Compression force at room temperature was measured with a load cell that was positioned in-line between compression plates. Prescribed heat flux was delivered based on power input, as quantified with the use of a reference sample in a thermal resistance network. Temperature was measured by an array of thermocouples. Software simulations were performed using finite element analysis (FEA) for structural deformation and computational fluid dynamics (CFD) for heat transfer under the combined effects of conduction and convection. The simulations provided estimates of deformed shape and thermal losses that were compared to experimental measurements. Mechanical stress-strain tests using three TMM replicate specimens at room temperature showed a linear stress-strain relationship from approximately 2% to 14% strain and a compressive modulus of elasticity ranging from 7.56 kPa to 12.7 kPa. Distributed temperature measurements under an imposed heat flux resulted in thermal conductivity between 0.89 W/(m·K) and 1.04 W/(m·K), specific heat capacity between 5590 J/(kg·K) and 6720 J/(kg·K) and thermal diffusivity between 1.29 × 10−7 m 2 /s to 1.71 × 10−7 m2/ s. Viscoelastic effects were observed to reach steady state after approximately 20 seconds, with full elastic recovery upon unloading. Thermal conductivity and thermal diffusivity were observed to decrease under mechanical compression, while specific heat capacity was observed to increase. The results affirm that thermal properties of tissue-mimicking material can be altered by mechanical compression. These findings can be applied to future investigation of temperature distribution during localized ablation by methods such as HIFU, and can be extended to refined material modeling of perfused tissue under compression.

Experimental Study on the Specific Heat Capacity Measurement of Water-Based Al2O3-Cu Hybrid Nanofluid by using Differential Thermal Analysis Method

2019 ◽  
Vol 15 ◽  
Author(s):  
Andaç Batur Çolak ◽  
Oğuzhan Yıldız ◽  
Mustafa Bayrak ◽  
Ali Celen ◽  
Ahmet Selim Dalkılıç ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermophysical Properties ◽  
Volume Concentration ◽  
Pure Water ◽  
Heat Capacity Measurement ◽  
Experimental Results ◽  
Hybrid Nanofluid ◽  
Capacity Measurement

Background: Researchers working in the field of nanofluid have done many studies on the thermophysical properties of nanofluids. Among these studies, the number of studies on specific heat are rather limited. In the study of the heat transfer performance of nanofluids, it is necessary to increase the number of specific heat studies, whose subject is one of the important thermophysical properties. Objective: The authors aimed to measure the specific heat values of Al2O3/water, Cu/water nanofluids and Al2O3-Cu/water hybrid nanofluids using the DTA method, and compare the results with those frequently used in the literature. In addition, this study focuses on the effect of temperature and volume concentration on specific heat. Method: The two-step method was used in the preparation of nanofluids. The pure water selected as the base fluid was mixed with the Al2O3 and Cu nanoparticles and Arabic Gum as the surfactant, firstly mixed in the magnetic stirrer for half an hour. It was then homogenized for 6 hours in the ultrasonic homogenizer. Results: After the experiments, the specific heat of nanofluids and hybrid nanofluid were compared and the temperature and volume concentration of specific heat were investigated. Then, the experimental results obtained for all three fluids were compared with the two frequently used correlations in the literature. Conclusion: Specific heat capacity increased with increasing temperature, and decreased with increasing volume concentration for three tested nanofluids. Cu/water has the lowest specific heat capacity among all tested fluids. Experimental specific heat capacity measurement results are compared by using the models developed by Pak and Cho and Xuan and Roetzel. According to experimental results, these correlations can predict experimental results within the range of ±1%.

Development of the room temperature protocol based on room temperature ionic liquids and surfactant ionic liquids for the synthesis of derivatives of 2-amino-thiazoles and thermo-physical analysis of the synthesized derivatives using TGA-DSC.

2020 ◽  
Vol 10 ◽  
Author(s):  
Chandrakant Sarode ◽  
Sachin Yeole ◽  
Ganesh Chaudhari ◽  
Govinda Waghulde ◽  
Gaurav Gupta
Keyword(s):  
Thermal Analysis ◽  
Heat Capacity ◽  
Ionic Liquids ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Room Temperature ◽  
Heat Capacity Data ◽  
General Strategy ◽  
Capacity Data ◽  
Derivatives Of

Aims: To develop an efficient protocol, which involves an elegant exploration of the catalytic potential of both the room temperature and surfactant ionic liquids towards the synthesis of biologically important derivatives of 2-aminothiazole. Objective: Specific heat capacity data as a function of temperature for the synthesized 2- aminothiazole derivatives has been advanced by exploring their thermal profiles. Method: The thermal gravimetry analysis and differential scanning calorimetry techniques are used systematically. Results: The present strategy could prove to be a useful general strategy for researchers working in the field of surfactants and surfactant based ionic liquids towards their exploration in organic synthesis. In addition to that, effect of electronic parameters on the melting temperature of the corresponding 2-aminothiazole has been demonstrated with the help of thermal analysis. Specific heat capacity data as a function of temperature for the synthesized 2-aminothiazole derivatives has also been reported. Conclusion: Melting behavior of the synthesized 2-aminothiazole derivatives is to be described on the basis of electronic effects with the help of thermal analysis. Additionally, the specific heat capacity data can be helpful to the chemists, those are engaged in chemical modelling as well as docking studies. Furthermore, the data also helps to determine valuable thermodynamic parameters such as entropy and enthalpy.

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