scholarly journals Discussion: “Measurement of the Thermal Conductivity of Noble Gases in the Temperature Range 1500 to 5000 Deg Kelvin” (Collins, D. J., and Menard, W. A., 1966, ASME J. Heat Transfer, 88, pp. 52–55)

1966 ◽  
Vol 88 (1) ◽  
pp. 55-56
Author(s):  
P. E. Liley
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Noble Gases ◽  
Temperature Range

A Tiny Detector Made of a Self-Heated Thermistor for Determining Thermal Conductivity of Biomaterials in Temperature Range 233~313K

2002 ◽  
Author(s):  
H. F. Zhang ◽  
S. X. Cheng ◽  
L. Q. He ◽  
A. L. Zhang ◽  
Y. Zheng ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Carotid Artery ◽  
Temperature Rise ◽  
Measurement Errors ◽  
Homogeneous Medium ◽  
Standard Samples ◽  
Temperature Range ◽  
A New Technique ◽  
Maximum Measurement

In this paper, a new technique, using a tiny thermistor with 0.3~0.5mm in diameter to determine thermal conductivity of biomaterials in wide temperature range, has been developed. Based on steady spherical heat transfer in an infinite homogeneous medium, thermal conductivity of the measured medium can be determined by power applied and temperature rise of the thermistor. Compared with recommended values, maximum measurement errors of standard samples, aqueous glycol and CaCl2 solutions, water and ice, are 5.1% in temperature range 233~313K. The thermal conductivities of rabbit’s liver, kidney, heart and carotid artery in temperature range 233~293K are determined. Error caused by measurement parameters, effects of the finite scale of the measured medium and the decoupler between the thermistor and the medium are analyzed.

scholarly journals Механизмы переноса тепла и температурная зависимость теплового сопротивления кристаллов CaLa-=SUB=-2-=/SUB=-S-=SUB=-4-=/SUB=-

2020 ◽  
Vol 62 (1) ◽  
pp. 186
Author(s):  
С.М. Лугуев ◽  
Н.В. Лугуева ◽  
Т.С. Лугуев
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Temperature Dependence ◽  
Debye Temperature ◽  
Temperature Range

The results of the study of the temperature dependence of the thermal resistance of CaLa2S4 crystals in the temperature range of 80–450 K according to the measurement of their thermal conductivity are presented. The mechanisms of heat transfer in samples with different technological background are established. The causes that determine the magnitude and characteristics of the temperature dependence of the thermal resistance of CaLa2S4 crystals in the region and above the Debye temperature are revealed.

scholarly journals A Study on Thermal Performance of Palladium as Material for Passive Heat Transfer Enhancement Devices in Thermal and Electronics Systems

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Gbeminiyi Musibau Sobamowo ◽  
S. A. Ibrahim ◽  
M. O. Salami
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Efficiency ◽  
Internal Heat ◽  
Transfer Model ◽  
Temperature Range ◽  
Extended Surface ◽  
External Conditions ◽  
Materials Used ◽  
Proper Material

In this work, the thermal behavior of fin made of palladium material under the influences of internal transfer mechanisms such as thermal radiation and temperature-dependent internal heat generation is investigated. The thermal model for the extended surface made of palladium as the fin material is first developed and solved numerically using finite difference method. The effects of various parameters on the heat transfer model of the extended surface are investigated. The results show that the rate of heat transfer through the fin and the thermal efficiency of the fin increase as the thermal conductivity of the fin material increases. This shows that fin is more efficient and effective for a larger value of thermal conductivity.  However, the thermal conductivity of the fin with palladium material is low and constant at the value of approximately 75 W/mK in a wider temperature range of -100oC and 227oC. Also, it is shown that the thermal efficiencies of potential materials (except for stainless steel and brass) for fins decrease as the fin temperatures increase. This is because the thermal conductivities of most of the materials used for fins decreases as temperature increases. However, keeping other fin properties and the external conditions constant, the thermal efficiency of the palladium is constant as the temperature of the fin increases within the temperature range of -100oC and 227oC. The study will assist in the selection of proper material for the fin and in the design of passive heat enhancement devices under different applications and conditions.

A High-Performance Heat Exchanger Using Modified Polyvinylidene Fluoride-Based Hollow Fibers

2012 ◽  
Vol 479-481 ◽  
pp. 115-119 ◽  
Author(s):  
Baoan Li ◽  
Han Han Fan
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Exchanger ◽  
Hollow Fiber ◽  
Polyvinylidene Fluoride ◽  
Small Diameter ◽  
Water System ◽  
Hollow Fibers ◽  
Thin Wall ◽  
Temperature Range

Plastic heat exchangers has the shortcomings of bulky, thick pipe wall with large thermal resistance, poor heat transfer, aging of plastic and a narrow temperature range. The key to increase the heat transfer performance of heat exchanger is improving thermal performance of heat conduction.To enhance heat transfer effects and expand the temperature range of using plastic heat exchanger, PVDF with good temperature resistance is used as matrix and modification with graphite fillers to prepare composite hollow fiber which has the advantage of small diameter, thin wall and good thermal conductivity. Also, composite materials hollow fibers are used to prepare shell and tube hollow fiber heat exchanger.The testing of "water - water" system for our heat exchanger module has been done, and the results indicate that adding graphite is helpful to improve thermal conductivity of PVDF-based heat conductive hollow fiber heat exchanger to a certain extent.hen the content of graphite is 3%, the heat transfer effect is the best.

Experimental Investigation of Natural Convection Heat Transfer of an Ionic Liquid in a Rectangular Enclosure Heated From Below

2011 ◽  
Author(s):  
Titan C. Paul ◽  
A. K. M. M. Morshed ◽  
Elise B. Fox ◽  
Ann Visser ◽  
Nicholas Bridges ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Ionic Liquid ◽  
Nusselt Number ◽  
Natural Convection ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Temperature Range

This paper presents an experimental study of natural convection heat transfer for an Ionic Liquid. The experiments were performed for 1-butyl-2, 3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, ([C4mmim][NTf2]) at a Rayleigh number range of 1.13×107 to 7.7×107. In addition to determining the convective heat transfer coefficients, this study also included experimental determination of thermophysical properties of [C4mmim][NTf2] such as, density, viscosity, heat capacity, and thermal conductivity. The results show that the density of [C4mmim][NTf2] varies from 1.437–1.396 g/cm3 within the temperature range of 10–50°C, the thermal conductivity varies from 0.125–0.12 W/m.K between a temperature of 10 to 70°C, the heat capacity varies from 1.015 J/g.K–1.760 J/g.K within temperature range of 25–340°C and the viscosity varies from 243cP–18cP within temperature range 10–75°C. The results for density, thermal conductivity, heat capacity, and viscosity were in close agreement with the values in the literature. Measured dimensionless Nusselt number was observed to be higher for the ionic liquid than that of DI water. This is expected as Nusselt number is the ratio of heat transfer by convection to conduction and the ionic liquid has lower thermal conductivity (approximately 20% of DI water) than DI water.

scholarly journals Процессы теплопереноса в мультиферроиках Bi-=SUB=-1-x-=/SUB=-Ho-=SUB=-x-=/SUB=-FeO-=SUB=-3-=/SUB=- (x=0-0.20)

2020 ◽  
Vol 62 (5) ◽  
pp. 771
Author(s):  
С.Н. Каллаев ◽  
А.Г. Бакмаев ◽  
Л.А. Резниченко
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Earth Element ◽  
Mean Free Path ◽  
Antiferromagnetic Phase ◽  
Structural Studies ◽  
Temperature Range ◽  
Noticeable Increase ◽  
Phase Transition Region ◽  
The Mean

The thermal diffusivity and thermal conductivity of Bi1-xHoxFeO3 multiferroics (x = 0-0.20) were studied in the high-temperature range 300-1200K. It has been established that alloying with rare earth element with holmium leads to a noticeable increase in heat capacity in a wide temperature range T> 300 K and to a significant change in the temperature anomalies of thermal diffusion and thermal conductivity of the phase transition region. The dominant mechanisms of phonon heat transfer in the region of ferroelectric and antiferromagnetic phase transitions are considered. The dependence of the mean free path on temperature has been determined. Research results are discussed in conjunction with structural studies.

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