scholarly journals Research on Influencing Factors of Current-carrying Temperature Rise on Connector Terminal of Current Circuit in UHVDC Converter Station

2021 ◽  
Vol 2083 (2) ◽  
pp. 022056
Author(s):  
Peng Liu ◽  
Jiajun Si ◽  
Jian Zhang ◽  
Lixian Zhou ◽  
Dongqing Li
Keyword(s):  
Contact Resistance ◽  
Contact Area ◽  
Contact Surface ◽  
Temperature Rise ◽  
Structure Type ◽  
Stable Operation ◽  
Obvious Effect ◽  
Contact Conditions ◽  
Alloy Plate ◽  
Tightening Torque

Abstract Relying on the high current temperature rise test, starting from three aspects of different materials, different structural strengths, and different contact conditions, the research on the current-carrying-temperature rise characteristics of the joint terminals of ±800kV UHVDC converter stations under different conditions is carried out. The results show that, for joint terminals of the same structure type and contact area, the difference in resistivity of joint terminals of different materials has a significant impact on the temperature rise level. When the material is the same, the temperature rise level can be reduced to a certain extent after the silver (tin) layer is added to the contact surface of the terminal. When the contact resistance of the joint terminal and the current density are the same, after increasing the contact area, the temperature rise and decrease level of the aluminum alloy plate lap type joint terminal is significantly better than other types of joint terminals. The contact resistance and temperature rise of the joint terminal decrease with the increase of the bolt tightening torque, and become stable when it reaches more than 80%. When the bolt tightening torque reaches more than 90%, the surface finish of the contact surface has no obvious effect on the contact resistance of the joint terminal. By controlling the material properties, structural strength, contact conditions, significantly reduces the temperature rise of the level of the joint terminal, effectively ensuring the safety ±800kV UHVDC converter station stable operation.

Experimental Study on the Drying Performance of the High Temperature Heat Pump Dryer

2012 ◽  
Vol 550-553 ◽  
pp. 3219-3223
Author(s):  
Xing Wang Zhu ◽  
Chun Xia Hu ◽  
Zhi Min Guo ◽  
Yu Gui Su
Keyword(s):  
High Temperature ◽  
Heat Pump ◽  
External Environment ◽  
Stable Operation ◽  
Obvious Effect ◽  
Electromagnetic Valve ◽  
Exhaust Temperature ◽  
Temperature Heat ◽  
High Temperature Heat Pump

In this paper，a high temperature heat-pump dryer and a corresponding semi-enclosed test drying room for using the dryer are built up respectively. While the average dry bulb of the external environment is 25°C and the relative humidity is 55%, the performance of the dryer is obtained when the dryer is running continuously for five hours. The results show that: the electromagnetic valve-capillary institution has an obvious effect on the lower the dryer exhaust temperature. It makes the suction temperature of compressor dropped 10 °C~15 °C, which can reduce the exhaust temperature and prevent compressor’s overheating. When the exhaust temperature keep at 100~110 °C, it can not only guarantee the temperature of wind coming from the dryer is high, but also can make sure the drying system’s long-term stable operation.

Ni-Al-Ti Ohmic Contacts with Preserved Form Factor and Few 10- 4 Ωcm2 Specific Resistance on 0.1-1 Ωcm p-Type 4H-SiC

2018 ◽  
Vol 924 ◽  
pp. 385-388 ◽  
Author(s):  
Roberta Nipoti ◽  
Maurizio Puzzanghera ◽  
Maria Concetta Canino ◽  
Giovanna Sozzi ◽  
Paolo Fedeli
Keyword(s):  
Form Factor ◽  
Contact Resistance ◽  
Contact Area ◽  
Room Temperature ◽  
Ohmic Contacts ◽  
Specific Resistance ◽  
Thickness Ratio ◽  
Specific Contact Resistance ◽  
Specific Contact ◽  
P Type

This study shows that a thin Ni film on Al/Ti/4H-SiC metal pads allows to preserve the pad form factor during a 1000 °C/2 min treatment, provided that the Al and Ti film thicknesses are sufficiently thin. Moreover, by reducing the Al to Ti thickness ratio, droplet formation in the contact area is avoided and a mirror-like appearance is obtained. This optimal contact morphology corresponds to a specific contact resistance of few 10-4Ωcm2at room temperature on p-type 4H-SiC with resistivity in the range 0.1 – 1 Ωcm.

scholarly journals Analysis of the Actual Contact Surface of Selected Aircraft Tires with the Airport Pavement as a Function of Pressure and Vertical Load

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 591
Author(s):  
Mariusz Wesołowski ◽  
Krzysztof Blacha ◽  
Paweł Pietruszewski ◽  
Paweł Iwanowski
Keyword(s):  
Contact Area ◽  
Contact Surface ◽  
Load Capacity ◽  
Surface Friction ◽  
Vertical Load ◽  
Tire Pressure ◽  
Wheel Load ◽  
Friction Tester ◽  
Flight Operations ◽  
Research Studies

The contact surface of the wheel with the airport surface is important for the safety of flight operations in the ground manoeuvring area. The area of the contact surface, its shape and stress distribution at the pavement surface are the subject of many scientists’ considerations. However, there are only a few research studies which include pressure and vertical load directly and its influence on tire-pavement contact area. There are no research studies which take into account aircraft tires. This work is a piece of an extensive research project which aims to develop a device and a method for continuous measurement of the natural airport pavement’s load capacity. One of the work elements was to estimate the relationship between wheel pressure and wheel pressure on the surface, and the area of the contact surface. The results of the research are presented in this article. Global experience in this field is cited at the beginning of the article. Then, the theoretical basis for calculating the wheel with the road surface contact area was presented. Next, the author’s research views and measurement method are presented. Finally, the obtained test results and comments are shown. The tests were carried out for four types of tires. Two of them were airplane tires from the PZL M28 Skytruck/Bryza and Sukhoi Su-22 aircraft. Two more came from the airport ASFT (airport surface friction tester) friction tester-one smooth ASTM; the other smooth retreaded type T520. The tires were tested in a pressure range from 200 to 800 kPa. The range of vertical wheel load on the pavement was 3.23–25.93 kN for airplane tires, and 0.8–4.0 kN for friction tester tires. The tests proved a significant influence of the wheel pressure value and wheel pressure on the surface on the obtained contact surface area of the wheel with the surface. In addition, it was noted that the final shape and size of the contact surface is affected by factors other than wheel pressure, tire pressure and dimensions.

scholarly journals Resistive-nanoindentation: contact area monitoring by real-time electrical contact resistance measurement

2019 ◽  
Vol 9 (3) ◽  
pp. 1008-1014 ◽  
Author(s):  
Solène Comby-Dassonneville ◽  
Fabien Volpi ◽  
Guillaume Parry ◽  
Didier Pellerin ◽  
Marc Verdier
Keyword(s):  
Contact Resistance ◽  
Real Time ◽  
Contact Area ◽  
Electrical Contact ◽  
Resistance Measurement ◽  
Electrical Contact Resistance ◽  
Image Position ◽  
Area Monitoring

Abstract

Experimental and Simulation Studies of Thermal Distribution on Modified Connector of Li-Ion Battery for Electric Vehicles Application

2016 ◽  
Vol 6 (5) ◽  
pp. 2064
Author(s):  
Agus Risdiyanto ◽  
Umar Khayam ◽  
Noviadi A. Rachman ◽  
Maulana Arifin
Keyword(s):  
Contact Resistance ◽  
Contact Area ◽  
Fire Hazard ◽  
Lithium Ion ◽  
Maximum Temperature ◽  
Silver Coating ◽  
Li Ion Battery ◽  
Steady State Condition ◽  
Li Ion ◽  
Dc Current

<p>One of the several failure cases in electric vehicle could be occured at the Lithium-ion (Li-ion) battery connectors when loaded by high current. This failure caused by bad contact of connectors so that the contact resistance increase and lead to high power losses, overheating, and it can even cause a fire hazard. This paper presents a thermal distributions of  Li-ion battery connectors on different coating material in relation to the value of contact resistance. There were two test samples of modeled: copper connection without coating and copper connection with silver coating. Each sample was loaded by the DC current of 350A, and temperature at the connection was measured until steady state condition reached and simulated by Solidwork software. The results show that the temperature at the inside contact area was higher than the outside contact area of connection that appears caused by higher of the contact resistance. Both measurement and simulation results have same tendency that copper connection with silver coating having lower contact resistance, lower maximum temperature, and lower losses about 32 % than copper connection without  coating. Silver coating can be considered as other alternative to prevent overheating, high losses, and failure in Li-ion battery connector.</p>

Thermal Contact Resistance at a Metal Foam-Solid Surface Interface

2011 ◽  
Author(s):  
Ehsan Sadeghi ◽  
Scott Hsieh ◽  
Majid Bahrami
Keyword(s):  
Thermal Conductivity ◽  
Contact Resistance ◽  
Effective Thermal Conductivity ◽  
Contact Area ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Metal Foams ◽  
Real Contact Area ◽  
The Real ◽  
Real Contact

Accurate information on heat transfer and temperature distribution in metal foams is necessary for design and modeling of thermal-hydraulic systems incorporating metal foams. The analysis of this process requires determination of the effective thermal conductivity as well as the thermal contact resistance (TCR) associated with the interface between the metal foams and adjacent surfaces/layers. In the present study, a test bed that allows the separation of effective thermal conductivity and thermal contact resistance in metal foams is described. Measurements are performed in a vacuum under varying compressive loads using ERG Duocel aluminum foam samples with different porosities and pore densities. Also, a graphical method associated with a computer code is developed to demonstrate the distribution of contact spots and estimate the real contact area at the interface. Our results show that the porosity and the effective thermal conductivity remain unchanged with the variation of compression in the range of 0 to 2 MPa; but TCR decreases significantly with pressure due to an increase in the real contact area at the interface. Moreover, the ratio of real to nominal contact area varies between 0 to 0.013, depending upon the compressive force, porosity, and surface characteristics.

Nano-Watt Heat Flux Sensor Considering Contact Resistance at Thermopile Junctions

2011 ◽  
Author(s):  
Sung-Ki Nam ◽  
Su-Heon Jeong ◽  
Sun-Kyu Lee
Keyword(s):  
Heat Flux ◽  
Contact Resistance ◽  
Contact Region ◽  
Complementary Metal Oxide Semiconductor ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Heat Flux Sensor ◽  
Contact Conditions ◽  
In Series ◽  
Flux Sensor

This paper presents design and fabrication procedures for nano-Watt resolution of heat flux sensor. To enhance the resolution, a contact resistance of thermopile is especially focused. CMOS (Complementary Metal-Oxide Semiconductor-compatible) process was used for deposition of gold and chromium which are composed of thermopile. The most important part of thermopile is the contact region of the junctions which generate electrical noises as well as thermoelectric power. The effect of contact conditions at junction point was investigated. The fabricated sensor has 100 thermocouples connected in series and its active junction is on the membrane which directly affects the sensitivity. Developed sensor system provides 0.0629V/nW of sensitivity and 1nW of high resolution.

Viscoelastic Contact of a Half-Plane Sliding Over a Slightly Wavy Rigid Surface

2014 ◽  
Author(s):  
N. Menga ◽  
C. Putignano ◽  
T. Contursi ◽  
G. Carbone
Keyword(s):  
Contact Problem ◽  
Contact Area ◽  
Analytical Procedure ◽  
Sliding Contact ◽  
Rigid Surface ◽  
Viscoelastic System ◽  
Contact Conditions ◽  
Partial Contact ◽  
Full Contact ◽  
Viscoelastic Contact

In this paper, the sliding contact of a rigid sinusoid over a viscoelastic halfplane is studied by means of an analytical procedure that reduced the original viscoelastic system to an elastic equivalent one, which has been already solved in [1]. In such a way, the solution of the original viscoelastic contact problem requires just to numerically solve a set of two integral equations. Results show the viscoelasticity influence on the solution by means of a detailed analysis of contact area, pressure and displacement distribution. A particular attention is paid to the transition from full contact to partial contact conditions.

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