scholarly journals Effect of Ceramic Coating on Indoor Thermal Conditions of Wooden House during Winter

2021 ◽  
Vol 46 (1) ◽  
pp. 19-24
Author(s):  
Takahisa Nakai ◽  
Keisuke Toba ◽  
Kenta Watanabe ◽  
Jianbo Huang ◽  
Susumu Kawamura
Author(s):  
Ozer Unal

Interest in ceramics as thermal barrier coatings for hot components of turbine engines has increased rapidly over the last decade. The primary reason for this is the significant reduction in heat load and increased chemical inertness against corrosive species with the ceramic coating materials. Among other candidates, partially-stabilized zirconia is the focus of attention mainly because ot its low thermal conductivity and high thermal expansion coefficient.The coatings were made by Garrett Turbine Engine Company. Ni-base super-alloy was used as the substrate and later a bond-coating with high Al activity was formed over it. The ceramic coatings, with a thickness of about 50 μm, were formed by EB-PVD in a high-vacuum chamber by heating the target material (ZrO2-20 w/0 Y2O3) above its evaporation temperaturef >3500 °C) with a high-energy beam and condensing the resulting vapor onto a rotating heated substrate. A heat treatment in an oxidizing environment was performed later on to form a protective oxide layer to improve the adhesion between the ceramic coating and substrate. Bulk samples were studied by utilizing a Scintag diffractometer and a JEOL JXA-840 SEM; examinations of cross-sectional thin-films of the interface region were performed in a Philips CM 30 TEM operating at 300 kV and for chemical analysis a KEVEX X-ray spectrometer (EDS) was used.


2018 ◽  
pp. 155-162 ◽  
Author(s):  
Sergei S. Kapitonov ◽  
Anastasia V. Kapitonova ◽  
Sergei Yu. Grigorovich ◽  
Sergei A. Medvedev ◽  
Taher Sobhy

In the article, the electrical and thermal processes in the LED lamp with varied parameters are investigated. Voltage and current measurements on all LEDs of the luminaire are carried out in the nominal operating mode. The power allocated to each LED is determined. The calculation of the LED crystal temperature was carried out using the developed thermal LED model based on the results of the measurements and by using “Multisim” program. It has been established that the temperature of the crystals of individual LEDs in the luminaire differ significantly, which leads to unfavourable thermal conditions for them and an increased likelihood of premature failure.


2017 ◽  
Vol 191 ◽  
pp. 176-195 ◽  
Author(s):  
Igor D. Rostov ◽  
Elena V. Dmitrieva ◽  
Alexander A. Vorontsov

2020 ◽  
Vol 38 (9A) ◽  
pp. 1257-1275
Author(s):  
Wisam M. Mareed ◽  
Hasanen M. Hussen

 Elevated CO2 rates in a building affect the health of the occupant. This paper deals with an experimental and numerical analysis conducted in a full-scale test room located in the Department of Mechanical Engineering at the University of Technology. The experiments and CFD were conducted for analyzing ventilation performance. It is a study on the effect of the discharge airflow rate of the ceiling type air-conditioner on ventilation performance in the lecture room with the mixing ventilation. Most obtained findings show that database and questionnaires analyzed prefer heights between 0.2 m to 1.2 m in the middle of an occupied zone and breathing zone height of between 0.75 m to 1.8 given in the literature surveyed. It is noticed the mismatch of internal conditions with thermal comfort, and indoor air quality recommended by [ASHRAE Standard 62, ANSI / ASHRAE Standard 55-2010]. CFD simulations have been carried to provide insights on the indoor air quality and comfort conditions throughout the classroom. Particle concentrations, thermal conditions, and modified ventilation system solutions are reported.


2018 ◽  
pp. 15-27 ◽  
Author(s):  
V. A. Gribkov ◽  
◽  
A. S. Demin ◽  
N. A. Epifanov ◽  
E. E. Kazilin ◽  
...  

2020 ◽  
pp. 75-86
Author(s):  
Sergio Antonio Camargo ◽  
Lauro Correa Romeiro ◽  
Carlos Alberto Mendes Moraes

The present article aimed to test changes in cooling water temperatures of males, present in aluminum injection molds, to reduce failures due to thermal fatigue. In order to carry out this work, cooling systems were studied, including their geometries, thermal gradients and the expected theoretical durability in relation to fatigue failure. The cooling system tests were developed with the aid of simulations in the ANSYS software and with fatigue calculations, using the method of Goodman. The study of the cooling system included its geometries, flow and temperature of this fluid. The results pointed to a significant increase in fatigue life of the mold component for the thermal conditions that were proposed, with a significant increase in the number of cycles, to happen failures due to thermal fatigue.


Author(s):  
Boris A. Sokolov ◽  
Pavel A. Shcherbina ◽  
Ivan B. Sishko ◽  
Aleksandr V. Shipovskiy Aleksandr ◽  
Aleksandr A. Lyapin ◽  
...  

The paper demonstrates the feasibility of using iodine as propellant for thrusters with closed electron drift and its economic viability. It describes a test setup for running experiments. It provides the results of experimental studies of the stationary plasma thruster using iodine as its propellant with xenon gas-passage hollow cathode, as well as of the operational mode of the thruster where a mixture of xenon and iodine is used. During tests gas dynamic and electrical properties of the thruster were analyzed. Thermal conditions in the iodine storage and supply system were studied. Conclusions were drawn on how the test object could be improved and upgraded. The paper describes the option to use a thermionic non-flow cathode as the compensator cathode for the operation of the iodine thruster. The paper provides the results of an experimental study of the prototype non-flow compensator cathode in diode mode. Based on the results of the studies an experimental facility was built for testing a thruster with non-flow compensator cathode. Key words: cathode, compensator cathode, thruster with closed electron drift, stationary plasma thruster, iodine.


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