• Elastomers and Composites
• /
• v.36 no.3
• /
• pp.153-161
• /
• 2001

The rubber pads era tank which undergo dynamic deformations with the sufficient amplitudes and frequencies lead to a considerable internal temperature rise due to the heat generation. The heat generation which is dependent on the viscoelastic characteristics or a rubber is due to the conversion of partial mechanical energy into thermal energy identical to the area oi hysteresis loop. Heat generation without adequate heat dissipation leads to heat build-up and the excessive temperature rite exerts a bad influence upon the performance and the life of rubber products. In this paper, temperature distributions of the rubber pads of a tank track subjected to dynamic loads are obtained under the assumption of the steady state. Heat generation rates used in this finite element analysis are acquired through experiments and the computed temperature fields are displayed in isothermal contour regions.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.3
• /
• pp.166-175
• /
• 2002

Tank track rubbers, which undergo dynamic stresses and strains under various road conditions, leads to a result of considerable internal temperature rise due to the heat generation. Since rubber materials are not fully elastic, a part of the mechanical energy is converted into heat because of the hysteresis loss. Heat generation without adequate heat dissipation leads to heat build-up, i.e. internal temperature rise which, if excessive, exerts a bad influence upon the performance and the life of the tank track rubbers. The purpose of this paper is to predict temperature distributions of the rubber components off tank track subjected to complex dynamic loads under various read conditions. In steady state analysis temperature fields are displayed in contour shapes, and in unsteady analysis the temperature variations of some important nodes are represented graphically with respect to the running time of the tank.

• Fire Science and Engineering
• /
• v.34 no.2
• /
• pp.54-63
• /
• 2020

Although fires caused by heat generation due to Cu₂O breeding in wire connections are well-known among fire investigators, there are few papers on the analysis and introduction of fire cases by heat generation due to Cu₂O breeding. This study analyzed fire statistics caused by heat generation in electrical connections and the phenomena and features of heat generation due to Cu₂O breeding. Then, a fire which occurred in the wire connection in a university lab by heat generation due to Cu₂O breeding was analyzed in more detail. This fire case could reach a conclusion that heat generation due to Cu₂O breeding caused a fire in the wire connection through the fire pattern investigation of fire origin, the visual investigation of wire connection, 3D CT, power-on-test, and stereoscopic microscopy, SEM and EDS analysis.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1997.10a
• /
• pp.137-142
• /
• 1997

From the results of study on the electrical characteristics of heat-generation mortar used graphite as fine aggregates is summerized as following. The primary purpose of this study is the mixing ratio of graphite (35%, 50%/Sg), curing conditions (autoclave, steam, surface, underwater) and shape change (length, section of the electric heat-generation mortar). In case of the test condition with the steam curing condition appearance to most excellent heat-generation reproducibility. And temperature a coefficient of electric heat-generation mortar change from is in inverse proportion to the temperature a coefficient of direct proportion as the ratio of graphite mixing increased.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.13 no.5
• /
• pp.422-430
• /
• 2001

In the present study, an evaporative generation process of ammonia-water solution film on the vertical plate was analysed. For the utilization of waste heat, hot water of low temperature was used as the heat source. The continuity, momentum, energy and diffusion equations for the solution film and vapor mixture were formulated in integral forms and solved numerically. Counter-current solution-vapor flow resulted in the refrigerant vapor of the higher ammonia concentration than that of co-current flow. Eve the rectification of refrigerant vapor was observed near the inlet of solution film in counter-current flow. For the optimum operation of generator using hot water, numerical experiments, based on the heat exchange and generation efficiencies. revealed the inter-relationships among the Reynolds number of the solution film and hot water, and the length of generator. Enhancement of heat and mass transport in the solution film was found to be very effective for the improvement of generation performance, especially at high solution flow rate.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.29 no.1
• /
• pp.10-14
• /
• 2009

Heat generation mechanism of ultrasound infrared thermography is still not well understood, yet and there are two reliable assumptions of heat generation, friction and thermo-mechanical effect. This paper investigates the principal cause of heat generation at fatigue crack with experimental and numerical approach. Our results show most of heat generation is contributed by friction between crack interface and thermo-mechanical effect is a negligible quantity.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2005.05a
• /
• pp.9-12
• /
• 2005

This paper investigated the temperature history of mass concrete mock up structure considering different heat generation by varying with mixture proportion. Setting time difference between high early strength mixture (E-P) and retarding mixture (R-F30) was 14.5hours. Incorporation of $30\%$ of fly ash contributed to $10^{\circ}C$ of hydration heat reduction. In generally used C and D combination, bottom concrete shows earlier hydration, while E-J combination showed reverse tendency and thus, this method can reduce the crack occurrence. Therefore, heat generation difference method has beneficial effect on reducing crack induced by hydration heat resulting from heat generation difference between surface and center section.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.5
• /
• pp.596-603
• /
• 2013

The increase of distributed power generation is closely related to interest in microgird including renuable energy sources such as photovoltaic (PV) systems and fuel cell. By the growing interest of microgrid all over the world, many studies on microgrid operation are being carried out. Especially operation technique which is core technology of microgrid is to supply heat and electricity energy simultaneously. Optimal microgrid scheduling can be established by considering CHP (Combined Heat and Power) generation because it produce both heat and electricity energy and its total efficiency is high. For this reason, CHP generation in microgrid is being spotlighted. In the near future, wide application of microgrid is also anticipated. This paper proposes a mathematical model for optimal operation of microgrid considering both heat and power. To validate the proposed model, the case study is performed and its results are analyzed.

• Korean Chemical Engineering Research
• /
• v.52 no.3
• /
• pp.294-301
• /
• 2014

This study focuses on analysis and comparison of entropy generation in various cross-sectional ducts along with fully developed laminar flow and constant uniform wall heat flux. The obtained results were compared in ducts with circular, semicircular, and rectangular with semicircular ends, equilateral triangular, and square and symmetrical hexagonal cross-sectional areas. These results were separately studied for aspect ratio of different rectangular shapes. Characteristics of fluid were considered at average temperature between outlet and inlet ducts. Results showed that factors such as Reynolds number, cross section, hydraulic diameter, heat flux and aspect ratio were effective on entropy generation, and these effects are more evident than heat flux and occur more in high heat fluxes. Considering the performed comparisons, it seems that semicircular and circular cross section generates less entropy than other cross sections.

• Journal of Electrochemical Science and Technology
• /
• v.13 no.3
• /
• pp.323-338
• /
• 2022

Heat generation and temperature of a battery is usually presented by an equation of current. This means that we need to adopt time domain calculation to obtain thermal characteristics of the battery. To avoid the complicated calculations using time domain, 'state of charge (SOC)' can be used as an independent variable. A SOC based calculation method is elucidated through the comparison between the calculated results and experimental results together. Experiments are carried for rapid resistive discharge of a large-capacitive lithium secondary battery to evaluate variations of cell potential, current and temperature. Calculations are performed based on open-circuit cell potential (SOC,T), internal resistance (SOC,T) and entropy (SOC) with specific heat capacity.