scholarly journals Моделирование процесса теплоотдачи сверхпроводящих пленок в резистивном состоянии

2021 ◽  
Vol 91 (3) ◽  
pp. 538
Author(s):  
М.А. Васютин ◽  
Н.Д. Кузьмичев ◽  
Д.А. Шилкин
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Thermal Conductivity ◽  
Low Temperatures ◽  
Heat Removal ◽  
Superconducting Films ◽  
Resistive State ◽  
Additional Heat ◽  
Film Substrate ◽  
Main Factor

The analysis of heat transfer in the contact-film-substrate system under conditions when the heat removal from the sample to the substrate is insufficient to ensure that the sample is not overheated. For low temperatures, a method is proposed for increasing the heat removal from thin-film samples by passing a high-density electric current through them. The property of an anomalously high thermal conductivity of copper at temperatures from 5 to 50 K was used as the main factor in enhancing heat removal. The heat equation for the film-substrate system was numerically solved under the condition of additional heat transfer to potential contacts. It has been shown that beryllium bronze contacts can provide efficient heat removal from samples of superconducting films in a resistive state under conditions of strong Joule heat release.

Submerged Jet Impingement Cooling of a Nanostructured Plate

2010 ◽  
Author(s):  
Muhsincan Sesen ◽  
Ali Kosar ◽  
Ebru Demir ◽  
Evrim Kurtoglu ◽  
Nazli Kaplan ◽  
...  
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Heat Flux ◽  
Silicon Wafer ◽  
Heat Removal ◽  
Jet Impingement ◽  
Wafer Surface ◽  
Small Scale ◽  
Copper Thin Film ◽  
Thin Film Layer

In this paper, the results of a series of heat transfer experiments conducted on a compact electronics cooling device based on single phase jet impingement techniques are reported. Deionized-water is propelled into four microchannels of inner diameter 685 μm which are used as nozzles and located at a nozzle to surface distance of 2.5mm. The generated jet impingement is targeted through these channels towards the surface of a nanostructured plate. This plate of size 20mmx20mm consisted of ∼600 nm long copper nanorod arrays with an average nanorod diameter of ∼150 nm, which were integrated on top of a silicon wafer substrate coated with a copper thin film layer (i.e. Cu-nanorod/Cu-film/Silicon-wafer). Heat removal characteristics induced through jet impingement are investigated using the nanostructured plate and compared to results obtained from a flat plate of copper thin film coated on silicon wafer surface. Enhancement in heat transfer up to 15% using the nanostructured plate has been reported in this paper. Heat generated by small scale electronic devices is simulated using a thin film heater placed on an aluminum base. Surface temperatures are recorded by a data acquisition system with the thermocouples integrated on the surface at various locations. Constant heat flux provided by the film heater is delivered to the nanostructured plate placed on top of the base. Volumetric flow rate and heat flux values were varied in order to better characterize the potential enhancement in heat transfer by nanostructured surfaces.

Characterisation of high thermal conductivity thin-film substrate systems and their interface thermal resistance

2018 ◽  
Vol 334 ◽  
pp. 233-242 ◽  
Author(s):  
Alireza Moridi ◽  
Liangchi Zhang ◽  
Weidong Liu ◽  
Steven Duvall ◽  
Andrew Brawley ◽  
...  
Keyword(s):  
Thin Film ◽  
Thermal Conductivity ◽  
Thermal Resistance ◽  
High Thermal Conductivity ◽  
Interface Thermal Resistance ◽  
Film Substrate

scholarly journals A new principle for the development of workwear for constructing highways in the Siberian Federal District of the Russian Federation

2021 ◽  
Vol 341 ◽  
pp. 00018
Author(s):  
Margarita Rodicheva ◽  
Anton Abramov ◽  
Elena Gneusheva ◽  
Olga Pchelenok
Keyword(s):  
Heat Transfer ◽  
Heat Removal ◽  
Warm Season ◽  
Federal District ◽  
Air Gap ◽  
Biological Factor ◽  
Siberian Federal District ◽  
Additional Heat ◽  
Air Gaps ◽  
The Russian Federation

The paper considered the problem of protecting workers from the biological factor during the construction of highways in the Siberian Federal District. A promising approach to meeting these requirements is proposed - the use of ventilated clothing. The authors developed a prototype of a protective overall. It was shown that when calculating its design, it was necessary to take into account the heat transfer in the air gaps. The authors worked out a numerical model of these processes and carried out calculations for the conditions in the warm season on the territory of the Siberian Federal District. It was found that with an air gap thickness of 20 mm, the additional heat removal provided by the air gap allowed maintaining the thermal comfort of a person when performing work with a load equivalent to 4 - 6 MET.

Modeling of Heat Transfer in Nanoscale Multilayer Solid-State Structures

2008 ◽  
Author(s):  
Shih-Kuo Wu ◽  
Ya-Wen Chou
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Thermal Conductivity ◽  
Solid State ◽  
Layer Thickness ◽  
Thermoelectric Materials ◽  
Radial Direction ◽  
Dissimilar Materials ◽  
Interface Condition ◽  
Solid State Structures

Modeling of heat transfer in nanoscale multilayer solid-state structures is presented in this article to seek a potential design of thermoelectric materials. The phonon radiative heat conduction equation is used to describe the heat transport behavior in nanoscale multilayer solid-state structures and the diffuse mismatch model is utilized to simulate the interface condition between two dissimilar materials. In this paper, the thermal conductivity of thin film superlattices, nano wire superlattices and nano tube superlattices were calculated. Then, size effects on the performance of thermoelectric micro coolers were examined in detail. The results show that the effective thermal conductivity of thermoelectric materials in superlattice structures decreases as the layer thickness decreases. In addition, the thermal conductivities of nano wire and nano tube superlattices are less than that of thin film superlattices when they have the same layer thickness. It is noted that the restriction on the radial direction not only decreases the thermal conductivity in radial direction but also in axial direction. Thus, nano wire and nano tube superlattices are potential materials for high performance thermoelectric devices.

Thermal Properties of Thin Films

1992 ◽  
Vol 284 ◽  
Author(s):  
J. C. Lambropoulos ◽  
S.-S. Hwang
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Resistance ◽  
Interfacial Thermal Resistance ◽  
Bulk Solid ◽  
Ceramic Films ◽  
Film Substrate ◽  
Conductivity Of Thin Films

ABSTRACTWe summarize various measurements of the thermal conductivity of thin ceramic films which show that the thermal conductivity of thin films with thickness in the micron and sub-micron range may be up to two orders of magnitude lower than the thermal conductivityof the corresponding bulk solid. The reduction in the thin film effective thermal conductivity is attributed to the interfacial thermal resistance across the film/substrate interface.

Supersonic Two-Phase Impinging Jet Heat Transfer

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Richard R. Parker ◽  
James F. Klausner ◽  
Renwei Mei
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Removal ◽  
Jet Impingement ◽  
Impinging Jet ◽  
High Heat Flux ◽  
Two Phase ◽  
Air Jet

The experimental heat transfer rates from a supersonic two-phase impinging air jet with disperse droplets are presented. The experimental configuration consists of an expanding disperse mixture of air and water through a converging–diverging nozzle, designed for Mach 3.26 with a liquid to air mass flow ratio ranging from 1.28% to 3.83%, impinging upon a thin film heater constructed of nichrome. The spatially varying heat transfer coefficient is measured, and peak values are on the order of 200,000 W/m2K. Two distinct regions of heat transfer are identified, one dominated by the jet impingement flow and another dominated by thin film heat transfer. The heat transfer coefficient of an impinging jet with dry air and no droplets is measured during the investigation as well. The heat transfer results are compared, and it is demonstrated that the addition of disperse water droplets to the jet significantly increases the heat removal capability of the jet as well as smoothing the spatial temperature distribution of the heater surface. As much as an order of magnitude increase in heat transfer coefficient is observed near the centerline of the jet and a factor of 3–5 increase is seen at a distance of approximately 4 nozzle diameters from the jet. The fundamental heat transfer coefficient measurements should benefit applications involving supersonic two-phase jets for high heat flux thermal management.

HEAT TRANSFER IN GAS-FILLED POWDERS AT LOW TEMPERATURES

1965 ◽  
Vol 43 (12) ◽  
pp. 2344-2360 ◽  
Author(s):  
D. E. Brodie ◽  
C. F. Mate
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Particle Size ◽  
Low Temperatures ◽  
High Pressures ◽  
Cell Model ◽  
Boundary Resistance ◽  
Kapitza Resistance ◽  
Helium Gas ◽  
A Cell

A cell model is developed for the discussion of heat transfer in uniform gas-filled powders at low temperatures. Calculations from the model are compared with measurements of the (average) thermal conductivity of powdered alumina in helium gas, at helium temperatures, under varying conditions of particle size, gas pressure, temperature, and load supported by the powder. The results at high pressures suggest the presence of a boundary resistance, similar to the Kapitza resistance, at the gas–solid interfaces within the powder.

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