• Transactions of Materials Processing
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• v.20 no.6
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• pp.439-449
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• 2011

The temperature distribution and subsequent permanent deformation of SS400 carbon steel plate subjected to an induction-based line heating process were studied by a numerical method involving coupled 3-D electromagnetic-thermal-structural analysis. The numerical study revealed that the amount of permanent deformation is strongly related to the Joule loss caused by such process conditions as input power and moving speed of the heat source. To validate the numerical analysis results, line heating experiments were carried out with a high frequency(HF) induction heating(IH) equipment capable of bending thick plate with the moving accuracy of ${\pm}0.1mm$ in heating coil position. The amount of permanent deformation increased with decreasing moving speed and increasing input power.

• Journal of Biosystems Engineering
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• v.40 no.3
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• pp.250-260
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• 2015

Purpose: Dual cylindrical microwave chambers equipped with an ohmic heating tube were designed and fabricated to maximize the electric field strength for expeditious heat treatment of particulate foods. Methods: The efficacy of the combination heater was investigated by simulating the electric field distribution by using COMSOL Multiphysics software. Results: All components of the designed microwave heating unit were suitable for transmitting maximal microwave power to the load. The simulated electric field distribution implied that single-mode microwave heating would be sufficient for the steady generation of a highly localized heating zone in the cavity. During impedance matching, the calculated reflection coefficient ($S_{11}$) was small, possibly implying minimal power loss and wave reflection in the designed microwave heating chamber. Conclusions: This study demonstrates the possibility of concentrating the microwave power at the centerline for a single-frequency microwave, for thermal treatment of multiphase foods without attenuating the microwave power.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.1
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• pp.38-42
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• 2017

This study proposes an idea for energy saving in apartment machine rooms. A conventional district heating system is equipped with constant-flow pumps and bypass valves to regulate pump differential pressure. Each family unit is equipped with a constant-flow on/off valve. This leads to excessive hot water circulation and a high return temperature. To reduce energy loss, this study assumes that each family unit is renovated with a heating valve which regulates the return temperature at $35^{\circ}C$. The hot water supply pump is also replaced with a pump with an inverter to vary flow rate. Expected energy savings is then estimated from field test data. According to the results, pump electricity consumption was reduced by 6,100 kWh for a family unit building over about half a year. The supply temperature can also be lowered by $5^{\circ}C$, which can contribute to a production of electricity of 10.3 kWh/ton of hot water.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.5
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• pp.257-263
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• 2018

It is a small injection molding machine for table top considering the material heating mechanism and the design and structure stability by securing the mechanism that compresses the inside of the material heating tube by using the electric actuator and by providing space between the body and the material heating tube to reduce heat loss Develop body. An electric actuator suitable for applying pressure to the inside of a material heating tube is a mechanical system composed of a rigid structure. Since a large force is repeatedly applied to the electric actuator and the push rod, the interaction between the moving parts and the dynamic Maximum stress through analysis and prediction of fatigue life of critical parts The pushrod reflects the structural analysis results of the electric actuator and the push rod, and pushes the inside of the material heating tube by the push rod to inject the molten material from the nozzle into the mold. The pushrod operates by the operation of the electric actuator. The material heated by the coil heater is ejected through the nozzle by the pressure of the material heating tube, and the material heating tube and the nozzle are also lowered at the same time as the push rod is lowered, so that the material is closely adhered to the mold. We want to study the completion of the injection.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.1901-1907
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• 2018

This paper is a study for accurate iron loss calculation of a cylindrical linear machine for free piston engine. This study presents that it is possible to accurately predict power loss in ferromagnetic laminations under magnetic flux by specially considering the dependence of hysteresis, classical, and excess loss components on the magnetic induction derivative. Significant iron loss in the armature core will not only compromise the machine efficiency, but may also result in excessive heating, which could lead to irreversible deterioration in the machine performance. Thus, correct prediction of power losses under a distorted flux waveform is therefore an important prerequisite to machine design, particularly when dealing with large apparatus where stringent efficiency standards are required. Finally, it will be discussed about the iron loss in various materials of cylindrical linear electric machine by geometric and electrical parameters. It will give elaborate information about the perfect design and design rules of cylindrical linear machine and in parallel tools for the calculation, simulation and design will be available.

• Food Science of Animal Resources
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• v.33 no.1
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• pp.103-108
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• 2013

This study was carried out to observe the effect of superheated steam combined with oven heating on the physico-chemical and sensory properties of chicken meat. Specially, chicken breasts and thighs were heated for 40 min in various heating formulations such as oven heating, superheated steam heating or a combination of two kinds of heating. In the physical properties measurement, the shear force was increased as superheated steam heating time and chicken thighs were higher than chicken breasts in all treatments (p<0.05). The highest level of water holding capacity was solely superheated steam treated chicken for 40 min (p<0.05). The $L^*$ value was decreased but $a^*$ value or $b^*$ value were increased after cooking. Chicken breast exhibited a higher colour value than chicken thigh. Superheated heating was effective to reduce heating loss as 22.64% (p<0.05). However, pH was not different depending on the heating formulation or part of the chicken meat (p>0.05). In the sensory test, the combination of 10 min oven heating and 30 min superheated steam heating was effective to create a good flavour of chicken meat. In this study, an optimum formulation was developed which was a combination of 10 min oven heating and 30 min superheated steam heating. It was more effective to improve the quality of chicken meat than the single heat treatment of chicken meat.

• Composites Research
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• v.30 no.3
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• pp.181-187
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• 2017

The effect of nanoscopic and microscopic Fe, $Fe_3O_4$, and Ni particles and their shapes and substrate materials on the heating behavior of thermoplastic polyurethane (TPU) adhesive films was investigated via induction heating. The heat generation tendency of $Fe_3O_4$ particles was higher than that shown by Fe and Ni particles in the TPU adhesive films. When the Fe and Ni particle size was larger than the penetration skin depth, the initial heating rate and maximum temperature increased with an increase in the particle size. This is attributed to the eddy current heat loss. The heating behavior of the TPU films with Ni particles of different shapes was examined, and different hysteresis heat losses were observed depending on the particle shape. Consequently, the flake-shaped Ni particles showed the most favorable heat generation because of the largest hysteresis loss. The substrate materials also affected the heating behavior of the TPU adhesive films in an induction heating system, and the thermal conductivity of the substrate materials was determined to be the main factor affecting the heating behavior.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.4
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• pp.307-314
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• 1998

A novel high power factor Dual Half Bridge Series Resonant Inverter (DHB-SRI) for an induction heating appliance with multiple loads is proposed to remove the interferential acoustic noise caused by the difference between operating frequencies of adjacent loads. The circuit enables independent full power range control of two induction heating elements by one inverter circuit and has minimum switching losses due to the zero voltage switching characteristic. According to the mode analysis, I will explain the operation of the proposed circuit. To evaluate the required cooling capacity, loss analysis is performed through deriving some loss equations. In order to obtain the power factor correction capability and to lessen the system size, suitable design guides are given. Using the designed values, the proto-type circuit with 2.8kW power consumption for each induction heating element is built and tested to verify the operation of the proposed circuit.

• Advances in materials Research
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• v.5 no.1
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• pp.21-34
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• 2016

Fire is one of the most destructive powers to which a building structure can be subjected, often exposing concrete elements to elevated temperatures. The relative properties of concrete after such an exposure are of significant importance in terms of the serviceability of buildings. Unraveling the heating history of concrete and different cooling regimes is important for forensic research or to determine whether a fire-exposed concrete structure and its components are still structurally sound or not. Assessment of fire-damaged concrete structures usually starts with visual observation of colour change, cracking and spalling. Thus, it is important to know the effect of elevated temperatures on strength retention properties of concrete. This study reports the effect of elevated temperature on the mechanical properties of the concrete specimen with polypropylene fibres and cooled differently under various regimes. In the heating cycle, the specimen were subjected to elevated temperatures ranging from $200^{\circ}C$ to $800^{\circ}C$, in steps of $200^{\circ}C$ with a retention period of 1 hour. Then they were cooled to room temperature differently. The cooling regimes studied include, furnace cooling, air cooling and sudden cooling. After exposure to elevated temperatures and cooled differently, the weight loss, residual compressive and split tensile strengths retention characteristics were studied. Test results indicated that weight and both compressive and tensile strengths significantly reduce, with an increase in temperature and are strongly dependent on cooling regimes adopted.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.8
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• pp.1073-1082
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• 1998

When thermal diffusivity is measured by laser flash method, the thermal diffusivity call be calculated front the assumption of the uniformly heated whole surface of the specimen. It has been known that the approximate 5% error is made by the non-uniform energy distribution on the specimen surface of laser pulse heat source. In this study, to obtain the highly-uniformed laser beam, which has both the low non-uniform heating error from non-uniform laser beam and the energy loss, research was carried out on no transmitting loss by optical fiber and high repetitions. In addition, heating error and thermal diffusivity were measured as the measuring positions were varied and compared with the results using the uniform and the non-uniform laser beams. In addition, dole to using the uniformalized laser beam, the whole surface of the specimen was heated uniformly and as a result, it was the thought that this was very effective to reduce the variations of the errors of the thermal diffusivity as the measuring positions were varied. It can be obtained that when the thermal diffusivity of POCO-AXM-5Q1 of SRM in NBS was measured with both the uniform and the non-uniform laser beams, the dispersion error of the former was from 2 to 2.5%, which was more improved than that of the latter.