• 한국의류학회지
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• 제35권3호
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• pp.292-303
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• 2011

This research suggested a draft proposal for a smart jacket design, which has applied wearable technologies to provide convenience in daily life. The smart jacket combined with a vest was the casual item for autumn and winter. The heating device was composed of the heating element, battery, controller, electric wire, connector, switch, and charger. A stable electronic conductor fiber of good heating effect with a flexible zigzag form has been selected for the heating element. The lighting device has been made in a way that attaches the LED and its power controller in the same mechanical device. As the result of the wearing test, the heating effect turned out to be effective in the order of: back, both the back and abdomen and only the abdomen. When wearing a smart jacket, the back and abdomen have been selected as favorable body parts for heating. Pockets and hems are selected as the adequate place to attach the LED lighting, and the brightness of LED lighting has turned out to be suitable and useful. Based on the test results, the first draft proposal has attached the heating element only in the back and its controller located in the inside pocket of the vest. In addition, the LED has been attached to the front pocket of the jacket. As to the second draft proposal, heating elements have been placed in the back and the abdomen. Each controller for the heating elements has been placed in the front and inside pocket of vest, and the LED lighting has been attached to the hem of the jacket. The smart jacket combined with a wearable device was assessed by functioning categories. The user showed a high satisfaction in the heating and illuminating function of a smart jacket.

• 한국산업융합학회 논문집
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• 제27권3호
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• pp.685-692
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• 2024

Currently used heating elements are metal and non-metal heating elements, including various types of heaters, and resistance line heating elements have a problem of decreasing thermal efficiency over time, so to solve this problem, a planar heating element using high-purity carbon materials and oxidation-resistant inorganic compounds was applied. Through the manufacture of planar heating elements using CNT, ruthenium composite materials, and ruthenium oxide, physicochemical performance and capacity were increased, and instantaneous responsiveness was increased. Through thick film technology applicable to various base bodies, fine patterns were formed by the screening method in consideration of the fact that the performance of the heat source depends on the viscosity and pattern shape. The heating element was manufactured by thick film printing technology by mixing ruthenium oxide, CNT, Ag, etc. The characteristics of each paste were analyzed through viscosity measurement, and STS 430 was used as a base. Surface temperature and efficiency were measured by testing heaters manufactured for small wind tunnels and real-vehicle experiments. The surface temperature decreased as the air volume increased, and the optimal system boundary was found to be about 200 mm. Among the currently used heating elements, this paper manufactured a planar heating element using thick film technology to find out the relationship between air volume and temperature, and to study the surface temperature.

• 대한조선학회 특별논문집
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• 대한조선학회 2007년도 특별논문집
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• pp.128-134
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• 2007

Induction heating process includes magnetic and thermal situations. In order to analyze the induction heating, material properties depending on temperature are considered. In this paper, three dimensional analysis of induction heating process for moving inductor is analyzed using moving coordinate. The skin effect is confirmed inside the steel plate in the electro-magnetic analysis. The heat generation at the initial state is different from that at the quasi-stationary state. Therefore, material properties depending on temperature must be considered. The results of finite element analysis agree well with the experimental temperature results.

• 한국세라믹학회지
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• 제55권5호
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• pp.440-445
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• 2018

To control the electrical properties of a SiC heating element, we sintered $SiC-ZrB_2$composites by using the spark plasma sintering method. The addition of $ZrB_2$ particles with lower electrical conductivity to the SiC matrices with comparatively higher electrical resistivity lowers the electrical resistivities of the composite material. The $ZrB_2$ particles aggregate to form large particles and 3-1, 3-2, and 3-3 networks, i.e., conduction paths. In our study, about $1-{\mu}m$-sized $ZrB_2$ powders start to form the conduction path at about 10 vol.% of addition, namely the threshold volume. The Joule heating experiment shows that 20 vol.% $ZrB_2$-added SiC heating element has outstanding heating efficiency.

• 융합신호처리학회논문지
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• 제12권4호
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• pp.355-361
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• 2011

기존 발열체의 전력제어는 On-Off 제어, 위상제어, PWM 제어를 사용해왔다. 최근 개발된 PTC 발열체를 기존의 방법으로 전력제어를 하였을 경우, 온도를 정밀하게 제어하지 못하고 인체에 유해한 전자파가 발생한다. 본 논문은 AC Cycles 가변을 이용한 PTC 열선의 전력 제어를 제안한다. 이것은 N개의 교류 cycle을 전력 제어의 단위로 간주하여, 각 cycle 마다 On-Off 여부를 결정하여 N cycles 내의 on-cycle 을 랜덤하게 배치하여 지속적으로 AC전력제어방법이다. 이 때 최소 전력량은 1/N이 되고 최대 전력량은 1이 되며 설정 값에 따라 on cycle의 수를 설정하여 N개의 단계로 일정하게 전력을 제어할 수 있다. PTC 열선과 온도센서를 사용한 발열 시스템에서 제안한 전력제어 방식이 전자파 발생과 온도제어 특성에서 우수함을 MATLAB simulation과 실험 및 측정을 통하여 확인하였다.

• 한국도로학회논문집
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• 제18권2호
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• pp.73-82
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• 2016

PURPOSES: The national highways and expressways in Korea constitute a total length of 17,951 km. Of this total length of pavement, the asphalt pavement has significantly deteriorated, having been in service for over 10 years. Currently, hot in-place recycling (HIR) is used as the rehabilitation method for the distressed asphalt pavement. The deteriorated pavement becomes over-heated, however, owing to uncontrolled heating capacity during the pre-heating process of HIR in the field. METHODS: In order to determine the appropriate heating method and capacity of the pre-heater at the HIR process, the heating temperature of asphalt pavement is numerically simulated with the finite element software ABAQUS. Furthermore, the heating transfer effects are simulated in order to determine the inner temperature as a function of the heating system (IR and wire). This temperature is ascertained at $300^{\circ}C$, $400^{\circ}C$, $500^{\circ}C$, $600^{\circ}C$, $700^{\circ}C$, and $800^{\circ}C$ from a slab asphalt specimen prepared in the laboratory. The inner temperature of this specimen is measured at the surface and five different depths (1 cm, 2 cm, 3 cm, 4 cm, and 5 cm) by using a data logger. RESULTS: The numerical simulation results of the asphalt pavement heating temperature indicate that this temperature is extremely sensitive to increases in the heating temperature. Moreover, after 10 min of heating, the pavement temperature is 36%~38% and 8%~10% of the target temperature at depths of 25 mm and 50 mm, respectively, from the surface. Therefore, in order to achieve the target temperature at a depth of 50 mm in the slab asphalt specimen, greater heating is required of the IR system compared to that of the gas. CONCLUSIONS : Numerical simulation, via the finite element method, can be readily used to analyze the appropriate heating method and theoretical basis of the HIR method. The IR system would provide the best heating method and capacity of HIR heating processes in the field.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.478-480
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• 2002

Heating by RF wave is divided into dielectric heating and induction heating. Dielectric heating and induction heating from outside the body have the compensatory heating pattern. While surface fat layer is heated by dielectric heating, it is not heated by induction heating. While the peripheral part at the middle of the electrodes is not heated by dielectric heating, it is heated by induction heating. By the simultaneous application both modalities, heating pattern seems to be more uniform and improved. Computer simulation of Finite Element Method (FEM) using ANSYS was conducted to dielectric heating with the results of above-mentioned feature. Theoretical considerations by the uniform RF magnetic field in a cylinder and textbooks support the feature of the above-mentioned heating pattern of induction heating. Further computer simulation of FEM using ANSYS will be conducted to simultaneous application of dielectric heating and induction heating to verify and will be reported.

• Journal of Welding and Joining
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• 제25권1호
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• pp.24-29
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• 2007

Finite element analysis for induction heating process including magnetic and thermal situations is presented. Because magnetic and thermal material properties vary with the temperature, material properties depending on temperature are considered. As the inductor moves, the solution domains corresponding to the inductor change into those of the air and the solution domains corresponding to the air change into those of the inductor. For these reasons, modeling of induction heating process is very difficult with a general purpose commercial programs. In this paper, three dimensional analysis of induction heating process for moving inductor is analyzed using moving coordinate. The skin effect is confirmed inside the steel plate in the electro-magnetic analysis. The distribution of heat generation at the initial state is different from that at the quasi-stationary state. Therefore, material properties depending on temperature must be considered. The calculated results of finite element analysis agree well with the experimental temperature results. This approach is suitable to solve magneto-thermal coupled problems.

• 한국정밀공학회지
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• 제10권3호
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• pp.198-204
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• 1993

The study is concerned with finite element analysis and design of axisymmetric deep drawing by local heating. When the bottom shape of a cup is not flat but in complex-shaped, i.e., hemispherical, the cup cannot be drawn in one or two processes in the conventional deep drawing process and the limit drawing ratio is limited as well. By introducing local heating selectively with regards to the heating position, the formability of the sheet metal can be greatly increased with the reduced number of processes. In the Process analysisthe rigid- viscoplastic finite element method is employed and the temperature effect is incorporated. Bishop's step-wise decoupled method is employed to analyze the thermomechanical interaction between deformation and heat transfer. Axisymmetric deep drawing of a hemisphere-bottomed cup has been analyzed for various combinations of heat application in the punch and the die. At the first stage of deep drawing stretch forming is practically carried out by firmly pressing the blankholder with the punch and the die heated at various levels of temperature. Then at the second stage the same cup is drawn for the saame or different combination of temperature. From the computation, it has thus been shown that the fromability of a cup is greatly increased in two-stage deep drawing with increased limet drawing ratio.

• 전자공학회논문지
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• 제53권11호
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• pp.151-159
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• 2016

본 논문에서는 다량의 온수가 필요하지 않는 세면을 목적으로 개발된 세라믹 발열체 기반 비저장식 순간 전기온수기를 제안한다. 입력되는 물을 가열하여 온수로 출수시키는 히팅모듈은 유량센서를 이용하여 입력되는 물을 감지하고 세라믹 히팅 모듈을 동작시킨다. 히팅 모듈 내부는 분당 1.5리터로 입수되는 물의 온도 대비 약 $15^{\circ}C$정도로 가열된 온수로 입수 2초 내에 출수시키기 위해 1 path 유로로 설계하였고 또한 설계의 타당성을 검증하기 위해 히팅모듈 내부 물의 흐름과 온도변화에 대한 열유동해석을 수행하였다. 기본 설계를 기초로 내부에 막대형 세라믹 발열체 1개가 내장된 히팅모듈을 제작하였다. 히팅모듈 제작 후 3단계로 온도 세팅 기능을 가지는 온수기 시제품을 제작하였다. 제작된 시제품을 분당 1.5리터의 물을 공급하는 상수도관에 연결하고 출수되는 물의 온도 및 시간을 측정한 실험에서 물 공급 후 2초 후에 온수기 3단 기준으로 공급되는 물 온도 대비 $18.3^{\circ}C$로 가열된 온수를 출수할 수 있음을 확인하였다. 그리고 대기전력 1w 미만, 순간 전력도 일반가정에서의 허용범위를 넘지 않는다. 성능 측정 결과들을 통해 제안된 비저장식 순간 전기온수기가 겨울철 세면용으로 가정, 고속도로휴게소, 공장 등의 세면대에 적용이 가능함을 확인하였다.