• Title/Summary/Keyword: Heat sensor

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An Experimental Study on Calibration Method of Heat Flux Sensor by using Helium Gas (헬륨을 이용한 열유속센서 검정방법의 실험적 연구)

  • Yang, Hoon-Cheul;Song, Chul-Hwa;Kim, Moo-Hwan
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1219-1224
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    • 2004
  • The objective of this study is to propose an experimental calibration facility in which a heat flux sensor can be calibrated under conductive condition by using helium gas. The heat flux calibration facility was designed, simulated and manufactured for use in a high heat transfer condition. It delivers heat fluxes up to a maximum of 35 KW $m^{-2}$. A copper block heated electrically with 3.5 KW power is designed to produce uniform temperature up to 600 K across its face. High heat fluxes are provided between hot plate and cold plate by 1 mm height helium filled gap. A cold plate is maintained around 300 K through pool boiling using a refrigerant and water-cooled heat exchanger. A simulation was conducted to verify the design of the main test section. To verify the performance of calibration facility, a heat flux sensor was examined. The measured heat fluxes were compared to the calculated one.

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The Micro Heat Flux Sensor using Electroplated Copper layers (구리 도금층을 이용한 미세 열유속 센서)

  • 오석환;전재철;김무환;이승섭
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.7
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    • pp.226-231
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    • 2000
  • New types of the micro heat flux sensor are designed and fabricated using SU-8 and Cu electroplating. And then calibrated under convection environment. The thermal path was made by SU-8 structure and electroplated Cu layers. The bottom surface of the micro heat flux sensor receives the heat flux from the wall, Then the heat flows along the Cu layers and drains out to the environment with producing the temperature difference at the upper layer of Cu. By measuring this temperature difference, the heat flux from the wall can be obtained. The temperature difference is measured by thermopile which is composed of Ni-Cr pairs or Al-chromel pairs. The calibration is accomplished under convection environment because it is most frequent situation. The range of the sensitivity is 0.11~2.02$\mu$V/(㎽/$\textrm{cm}^2$) for the various heat flux and Reynolds numbers.

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Development of Micro-machined Heat Flux Sensor by using MEMS technology (MEMS를 이용한 미세 열유속센서의 개발)

  • Yang, Hoon-Cheul;Song, Chul-Hwa;Kim, Moo-Hwan
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1364-1369
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    • 2004
  • New method for the design, fabrication, and calibration of micro-machined heat flux sensor has been developed. Two types of micro-machined heat flux sensor having different thicknesses of the thermal-resistance layer are fabricated using the MEMS technique. Photo-resist patterning using a chrome mask, bulk-etching and copper-nickel sputtering using a shadow mask are applied to make heat flux sensors, which are calibrated in the convection-type heat flux calibration facility. The sensitivity of the device varies with thermal-resistance layer, and hence can be used to measure the heat flux in heat-transfer phenomena.

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Theoretical study of flow and heat transfer around silicon bridge in a flow sensor (유속 센서의 실리콘 브리지 주위의 유동 및 열전달 수치해석에 관한 연구)

  • Hwang, Ho-Yeong;Kim, Ho-Yeong;Jeong, Jin-Taek
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.4
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    • pp.1376-1384
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    • 1996
  • Measuring the velocity of fluid flow, semiconductor flow sensors are widely used in the various fields of engineering and science such as the semiconductor manufacturing processes and electronic control engines for automobiles. In the near future, this type of sensors will replace present hot wire type sensors or other type flow sensor due to its low price, easy handling and small size. To develop the advanced semiconductor flow sensor, it is necessary to obtain characteristics of the flow and the heat transfer around the sensor in advance. In the present study, the theoretical analysis including mathematical modeling and numerical calculation to predict the characteristics of heat transfer and flow field around the sensor was carried out. The main parameters for optimum design of the flow sensor are the free stream velocity, the heat generation rate of silicon arm and the distance between arms. Effects of these parameters on flow and heat transfer around the sensor and the temperature difference between arms are examined.

Fabrication and evaluation of a micro heat flux sensor using thermopile (열전대를 이용한 미세 열유속 센서의 제작 및 평가)

  • Kim Jung-Hoon;Kim Bum-Seok;Cho Hyung-Hee;Kim Yong-Jun
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1210-1213
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    • 2005
  • Micro heat flux sensor is used in various industries to measure heat flux. In this study, a micro heat flux sensor is fabricated using the MEMS (Micro Electro Mechanical Systems) techniques. The fabricated sensor is composed in thermopile for sensor and SU-8 for thermal resistance layer. The new method of fabrication SU-8 is proposed in this study. The sensitivity is $44\;\mu{V/(W/cm^2)}$ at steady state and Reynolds number is 91322.

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Experimental and Numerical Analysis of Heat Transfer Phenomena in a Sensor Tube of a Mass Flow Controller (질량 유량계 센서관에서의 열전달 현상에 대한 수치적 해석 및 실험적 연구)

  • Jang, Seok-Pil;Kim, Sung-Jin;Choi, Do-Hyung
    • Proceedings of the KSME Conference
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    • 2000.04b
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    • pp.154-161
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    • 2000
  • As a mass flow controller is widely used in many manufacturing processes for controlling a mass flow rate of gas with accuracy of 1%, several investigators have tried to describe the heat transfer phenomena in a sensor tube of an MFC. They suggested a few analytic solutions and numerical models based on simple assumptions, which are physically unrealistic. In the present work, the heat transfer phenomena in the sensor tube of the MFC are studied by using both experimental and numerical methods. The numerical model is introduced to estimate the temperature profile in the sensor tube as well as in the gas stream. In the numerical model, the conjugate heat transfer problem comprising the tube wall and the gas stream is analyzed to fully understand the heat transfer interaction between the sensor tube and the fluid stream using a single domain approach. This numerical model is further verified by experimental investigation. In order to describe the transport of heat energy in both the flow region and the sensor tube, the Nusselt number at the interface between the tube wall and the gas stream as well as heatlines is presented from the numerical solution.

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A Study on Calibration of Heat Flux Sensor by using Convective Heat Transfer (대류방식을 이용한 열유속센서의 검정에 관한 연구)

  • Yang, Hoon-Cheul;Song, Chul-Hwa;Kim, Moo-Hwan
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1358-1363
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    • 2004
  • The objective of this work is to propose calibration facility in which a thin film type heat flux sensor can be calibrated under convective flow condition by using a small wind tunnel with the constant temperature plate condition. A small wind tunnel has been built to produce a boundary layer shear flow above a constant temperature copper plate. 12-independent copper blocks, thin film heaters, insulators and temperature controllers were used to keep the temperature of flat plate constant at a specified temperature. Three commercial thin film-type heat flux sensors were tested. Convective calibrations of these gages were performed over the available heat flux range of $1.4{\sim}2.5kW/m^2$. The uncertainty in the heat flux measurements in the convective-type heat flux calibration facility was ${\pm}2.07%$. Non-dimensional sensitivity is proposed to compare the sensitivity calibrated by manufacturer and that of experiment conducted in this study.

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Study on Optimal Structure of Low Power Microheater to Remain Stability at High Temperature (고온에서 안정한 저전력 마이크로히터 구조 최적화 연구)

  • Lim, Woonhyun;Kondalkar, Vijay;Lee, Keekeun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.68 no.1
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    • pp.69-76
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    • 2019
  • Microheaters with different structures were fabricated and compared to find an optimal configuration enhancing the performances of $C_2H_2$ gas sensor. Three temperature sensors were integrated on the surface of the insulation layer over the microheater, and resistance changes were observed to check the generated heat from the microheater. A low operating voltage of 1mV was applied to the temperature sensor to minimize any influence of thermal heat from the resistance type temperature sensor, whereas high voltages in the range between 10 and 20V were applied to the microheater. A microheater structure generating maximum heat at low voltage was determined. The generated heat was verified by the temperature sensors on the top of the $Si_3N_4$ and infrared camera. A long term stability and accuracy of the microheater were observed. The developed microheater was applied to enhance the performances of $C_2H_2$ gas sensor and successfully confirmed that the developed microheater greatly contributes to the improvement of sensitivity and selectivity of gas sensor.

Evaluation about Dielectric Property of Heat Transfer Fluids for Fuel Cell Vehicle using Cylindrical Multi-Terminal Capacitive-Conductive Sensor (원통형 다전극식 정전용량-전기전도도 센서를 이용한 연료전지 차량용 냉각수의 유전특성 평가)

  • Kim, Jae-Hoon;Kim, Ju-Han;Kim, Yoon-Hyung;Choi, Kang-Wal;Han, Sang-Ok;Yong, Gee-Joong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.6
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    • pp.1087-1094
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    • 2010
  • We have developed a cylindrical multi-terminal capacitive-conductive sensor that could be attached to the internal surface of cooling system pipe to evaluate capacitance and conductivity of heat transfer fluid. It was used as measuring system to diagnose insulating condition, by which was kept a insulating resistance of inner stack and at the same time was cooled electrochemical heat of reaction of FCEV(fuel cell electric vehicle) stack that used a compressed hydrogen gas reacting with oxygen in accordance with variation on thermal degradation of nonconductive heat transfer fluid. Also to assess diagnosis characteristics of heat transfer fluid, i.e. coolant, we have performed accelerated aging test using developed sensor attached to cooling system. Consequently, it was measured dielectric and electric resistance of coolant to estimate and analyse for dielectric properties by degradation condition.