Thermal Property Measurement of Semiconductor Melt Using Modified Laser Flash Method

2003 ◽  
Author(s):  
Bochuan Lin ◽  
Shen Zhu ◽  
Heng Ban ◽  
Chao Li ◽  
Rosalia N. Scripa ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Laser Flash ◽  
Laser Flash Method ◽  
Flash Method ◽  
Transient Temperature ◽  
Standard Laser

This study further develops the standard laser flash method for the measurement of multiple thermal properties of semiconductor melts. The standard laser flash method is widely used to measure thermal diffusivity of solids. Our modified procedure allows thermal diffusivity, thermal conductivity, and specific heat capacity of molten semiconductor material to be determined simultaneously. The transient heat transfer process in the melt and its quartz container was computationally studied in detail. A fitting procedure based on the numerical result and the least root-mean-square error fitting to the experimental data was used to extract thermal diffusivity, specific heat capacity, and thermal conductivity. The results for tellurium (Te) at 873 K: specific heat capacity 300.2 J/kg K, thermal conductivity 3.50 W/m K, thermal diffusivity 2.04×10−6 m2/s, are in good agreement with data published in the literature. Furthermore, uncertainty analysis showed quantitatively the effect of sample geometry, transient temperature measured, and the energy of the laser pulse on the results.

Thermal Conductivity of Nano-Pore Dispersed Y-PSZ Fabricated by EB-PVD

2006 ◽  
Vol 317-318 ◽  
pp. 509-512
Author(s):  
Byung Koog Jang ◽  
Norio Yamaguchi ◽  
Hideaki Matsubara
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Coating Thickness ◽  
Laser Flash ◽  
Flash Method ◽  
Columnar Microstructure ◽  
Coating Layers ◽  
Fractured Surface

ZrO2-4mol% Y2O3 coatings on zirconia substrate were deposited by EB-PVD. Influence of the coating thickness on thermal conductivity and thermal diffusivity of coated samples is examined. The fractured surface of the coated samples reveals a columnar microstructure consisting of feather-like structure. We have adopted a laser flash method for thermal diffusivity and specific heat capacity of coated samples. It was found that the thermal conductivity of the coating layers was strongly dependent on coating thickness. The thermal conductivity of coating layers shows increasing tendency with increasing the coating thickness.

scholarly journals Comparative study of thermal transport in Zea mays straw and Zea mays heartwood (cork) boards

2010 ◽  
Vol 14 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Sunday Etuk ◽  
Louis Akpabio ◽  
Ita Akpan
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Zea Mays ◽  
Thermal Diffusivity ◽  
Comparative Study ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermal Transport ◽  
Insulation Material ◽  
Thermal Absorptivity

Thermal conductivity values at the temperature of 301-303K have been measured for Zea mays straw board as well as Zea mays heartwood (cork) board. Comparative study of the thermal conductivity values of the boards reveal that Zea mays heartwood board has a lower thermal conductivity value to that of the straw board. The study also shows that the straw board is denser than the heartwood board. Specific heat capacity value is less in value for the heartwood board than the straw board. These parameters also affect the thermal diffusivity as well as thermal absorptivity values for the two types of boards. The result favours the two boards as thermal insulators for thermal envelop but with heartwood board as a preferred insulation material than the straw board.

Influence of Mesocarp Fibre Inclusion on Thermal Properties of Foamed Concrete

2021 ◽  
Vol 87 (1) ◽  
pp. 1-11
Author(s):  
Siti Shahirah Suhaili ◽  
Md Azree Othuman Mydin ◽  
Hanizam Awang
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Volume Fraction ◽  
Thermal Constant ◽  
Volume Fractions ◽  
Foamed Concrete

The addition of mesocarp fibre as a bio-composite material in foamed concrete can be well used in building components to provide energy efficiency in the buildings if the fibre could also offer excellent thermal properties to the foamed concrete. It has practical significance as making it a suitable material for building that can reduce heat gain through the envelope into the building thus improved the internal thermal comfort. Hence, the aim of the present study is to investigate the influence of different volume fractions of mesocarp fibre on thermal properties of foamed concrete. The mesocarp fibre was prepared with 10, 20, 30, 40, 50 and 60% by volume fraction and then incorporated into the 600, 1200 and 1800 kg/m3 density of foamed concrete with constant cement-sand ratio of 1:1.5 and water-cement ratio of 0.45. Hot disk thermal constant analyser was used to attain the thermal conductivity, thermal diffusivity and specific heat capacity of foamed concrete of various volume fractions and densities. From the experimental results, it had shown that addition of mesocarp fibre of 10-40% by volume fraction resulting in low thermal conductivity and specific heat capacity and high the thermal diffusivity of foamed concrete with 600 and 1800 kg/m3 density compared to the control mix while the optimum amount of mesocarp fibre only limit up to 30% by volume fraction for 1200 kg/m3 density compared to control mix. The results demonstrated a very high correlation between thermal conductivity, thermal diffusivity and specific heat capacity which R2 value more than 90%.

Thermal Properties of Electro Insulating Paper

2019 ◽  
Vol 955 ◽  
pp. 25-30
Author(s):  
Lucie Marackova ◽  
Veronika Melcova ◽  
Josef Samek ◽  
Oldrich Zmeskal
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Temperature Response ◽  
Differential Method ◽  
Thermal Parameters ◽  
Insulating Paper ◽  
Steady State Temperature

This paper is focused on the determination of thermal parameters (thermal conductivity, thermal diffusivity, and specific heat capacity) of electrical insulating paper from various producers. The transient step-wise method was used to determine all thermal parameters simultaneously. Evaluation was carried out using the differential method. Thermal conductivity was determined from the steady-state temperature response on thickness (corresponding to the number of paper layers), while thermal diffusivity and specific heat capacity was obtained from the dependence of derivative maximum and the corresponding temperature on thickness. Four electro insulating papers differing by composition and thickness: materials NKN (Nomex-Kapton-Nomex), DMD (Dacron-Mylar-Dacron), TFT (TufQUIN TFT 50) and TVAR (ThermaVolt AR) were studied. As a result, the highest value of thermal conductivity (0.17 W/m/K) was determined for the DMD. Remaining three materials possessed thermal conductivity about 0.12 W/m/K. However, differences in specific heat capacity and thermal diffusivity were found to be significantly higher. The lowest specific heat capacity was found for the DMD sample (1200 J/kg/K), while the highest specific heat capacity was found for TVAR sample (4000 J/kg/K).

Laser Flash Measurement of Samples With a Transparent Reference Layer

2009 ◽  
Author(s):  
Heng Ban ◽  
Zilong Hua
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Temperature Response ◽  
Front Surface ◽  
Laser Flash ◽  
Laser Flash Method ◽  
Flash Method ◽  
Thermal Diffusivity Measurement ◽  
Reference Layer

The laser flash method is a standard method for thermal diffusivity measurement. This paper reports the development of a method and theory that extends the standard laser flash method to measure thermal conductivity and thermal diffusivity simultaneously. By attaching a transparent reference layer with known thermal properties on the back of a sample, the thermal conductivity and thermal diffusivity of the sample can be extracted from the temperature response of the interface between the sample and the reference layer to a heating pulse on the front surface. The theory can be applied for sample and reference layer with different thermal properties and thickness, and the original analysis of the laser flash method becomes a limiting case of the current theory with an infinitely small thickness of the reference layer. The uncertainty analysis was performed and results indicated that the laser flash method can be used to extract the thermal conductivity and diffusivity of the sample. The results can be applied to, for instance, opaque liquid in a quartz dish with silicon infrared detector measuring the temperature of liquid-quartz interface through the quartz.

Thermal Properties Measurement of Particulate Fouling Samples of Air-Cooled Heat Exchangers Using Laser Flash Method

2020 ◽  
Author(s):  
Arjun Sharma ◽  
M. D. Islam ◽  
Ebrahim Al Hajri
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Middle East ◽  
Specific Heat ◽  
Thermophysical Properties ◽  
Heat Exchangers ◽  
Laser Flash ◽  
Flash Method ◽  
Particulate Fouling ◽  
Major Factors

Abstract Fouling is one of the major factors that drastically affects heat exchanger performance. Especially in Middle East where most of the heat exchangers are air cooled due to scarcity of water. As these heat exchangers are placed in a harsh climate, they are at high risk of low performance due to dusty/sticky particulate fouling. In order to identify possible active/passive methods to control or ideally eliminate particulate fouling, it is desirable to know exact thermophysical properties of such particulate fouling. This study presents thermophysical property characterization of selected fouling samples from eight different fin fan heat exchangers installed in an oil & gas facility in the Middle East. Laser flash Analysis (LFA) method is a well-known technique for measurement of the thermophysical properties: thermal diffusivity, specific heat and thermal conductivity of materials. A new technique was developed to prepare powder particulate fouling samples to make them as disc shaped samples while maintaining the range of ± 12 mm diameter and ± 2 mm thickness. The LFA measurements was conducted using LFA 447 Nano Flash Netzsch over the temperature range from 25 °C to 125°C. The thermal diffusivity was measured with an accuracy of ± 3% and the specific heat capacity with an accuracy of ± 5%. As the thermal conductivity is a product of these two measured values, is calculated with an accuracy of ± 5.8% and the measurement repeatability was within 2%.

Sign in / Sign up

Export Citation Format

Share Document