• Title/Summary/Keyword: Heat flowmeter method

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A Study on the Metering and the Rating Methods of Heat in Apartment Houses with Centralized Heating System (중앙집중난방방식 공동주택의 난방열량 계량 및 요금부과방안 연구)

  • Lee, Tae-Won;Kim, Yong-Ki
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.27-32
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    • 2009
  • The measuring apparatus such as heat meter is legally obliged to be installed and used for heat rating with heat or flow rate in residential buildings in Korea. There are two kinds of apparatus to measure heat consumed at each households, i.e., heat meter and hot water flowmeter. Contrast to the most of buildings with hot water flowmeter well being used for rating, heat meters have been used only 42.6% in the buildings with central heating system. But there is a critical problem in the course of using hot water flowmeter for heat rating, yielding distorted and unfair result which is different from the real value of heat supplied. Experiments with several parameters were carried out in this study to analyze this phenomenon quantively and alternative methods were proposed for rational heat rating.

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A Study of the Experiment and the Calculation Method on the Coolant Flow Rate of Engine and Vehicle Cooling System (엔진 및 차량냉각계의 냉각수유량 측정실험 및 계산방법에 관한 연구)

  • 오창석;유택용;이은현;최재권
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.6
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    • pp.1-7
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    • 1999
  • In this study, the prediction method of coolant flow rates has been developed and applied to an engine and vehicle cooling system. The flow rate passing through each component of the system is very important parameter to evaluate the heat transfer process form the combustion gas to the coolant and the heat rejection process form the radiator /heater to the ambient air. However, the present study reveals that the measurement using the flowmeter fails to give practical flow rates due to its additive resistance. In contrast, the present method which uses the parallel and serial relationship of flow resistance proved to be a good tool to predict the real flow rates. It can be also used to design the cooling system in the incipient stage of engine/vehicle development . The procedure was coded to the computer program so as to use it flexibly and, in the future, to expand it into an independent design tool of the whole cooling system including the heat release and rejection.

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Design and Evaluation of Ultrasonic Flow Meter for High Temperature by Using Finite Element Method (유한요소법을 이용한 고온용 초음파 유량센서의 설계 및 평가)

  • Lee, Joo-Hee;Kim, Chang-Il;Paik, Jong-Hoo;Cho, Jeong-Ho;Jeong, Young-Hun;Lee, Young-Jin;Nahm, Sahn
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.11
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    • pp.859-864
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    • 2011
  • An operation temperature of $Pb(Zr,Ti)O_3$ based piezoelectric ultrasonic flowmeter was generally restricted to below 200$^{\circ}C$ due to a low depoling temperature of its ceramic material. Thus, a new designed piezoelectric ultrasonic flowmeter was fabricated in order to protect from the extremely hot fluid. Its structure is optimized by a finite element method to effectively stop heat flowing along a waveguide. Various materials such as Cu, Al, SUS were examined as a multi-plate radiation shield to enhance the performance of piezoelectric ultrasonic flowmeter. The SUS was evaluated as the most effective material to enhance the performance of piezoelectric ultrasonic flowmeter. As the number of plates of the radiation shield increased, the temperature at piezoelectric transducer away from the hot fluid was constantly decreased with a ratio of 3.12$^{\circ}C$ per the plate number.

Signal processing method based on energy ratio for detecting leakage of SG using EVFM

  • Xu, Wei;Xu, Ke-Jun;Yan, Xiao-Xue;Yu, Xin-Long;Wu, Jian-Ping;Xiong, Wei
    • Nuclear Engineering and Technology
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    • v.52 no.8
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    • pp.1677-1688
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    • 2020
  • In the sodium-cooled fast reactor, the steam generator is a heat exchange device between sodium and water, which may cause leakage, resulting in a sodium-water reaction accident, which in turn affects the safe operation of the entire nuclear reactor. To this end, the electromagnetic vortex flowmeter is used to detect leakage of the steam generator and its signal processing method is studied in this paper. The hydraulic experiment was carried out by using water instead of liquid sodium, and the sensor output signal of the electromagnetic vortex flowmeter under different gas injection volumes was collected. The bubble noise signal is reflected by the base line of the sensor output signal. According to the relationship between the proportion of the bubble noise signal in the sensor output signal and the gas injection volume, a signal processing method based on the energy ratio calculation is proposed to detect whether the water contains bubbles. The gas injection experiment of liquid sodium was conducted to verify the effectiveness of the signal processing method in the detection of bubbles in sodium, and the minimum detectable leak rate of water in the steam generator was detected to be 0.2 g/s.

A Comparison Study of Heat Loss Characteristics in Monofilament and Multifilament Superconducting Coils Driven with AC Currents (단일필라멘트와 다중필라멘트 초전도 코일의 교류 전류에 의한 발열 특성 비교 평가)

  • Hwang, S.M.;Kim, K.;Kang, C.S.;Lee, S.J.;Lee, Y.H.
    • Progress in Superconductivity
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    • v.13 no.2
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    • pp.111-116
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    • 2011
  • Since superconducting wires have no resistance, electromagnets based on the superconducting wires produce no resistive heating with DC current as long as the current does not exceed the critical current of the wire. However, unlike resistive wires, superconducting wires exhibit AC heat loss. Embedding fine superconducting filaments inside copper matrix can reduce this AC loss to an acceptable level and opens the way to AC-capable superconducting coils. Here, we introduce an easy and accurate method to measure AC heat loss from sample superconducting coils by measuring changes in the rate of gas helium outflow from the liquid helium dewar in which the sample coil is placed. This method provides accurate information on total heat loss of a superconducting coil without any size limit, as long as the coil can fit inside the liquid helium dewar. With this method, we have evaluated AC heat loss of two superconducting solenoids, a 180-turn solid NbTi wire with 0.127 mm diameter (NbTi coil) and a 100-turn filamented wire with 1.4 mm diameter where 7 NbTi filaments were embedded in a copper matrix with copper to NbTi ratio of 6.7:1 (NbTi-Cu coil). Both coils were wound on 15 mm-diameter G-10 epoxy tubes. The AC heat losses of the NbTi and NbTi-Cu coils were evaluated as $53{\pm}4.7\;{\mu}W/A^2Hzcm^3$ and $0.67{\pm}0.16\;{\mu}W/A^2Hzcm^3$, respectively.

Cooling characteristics of the multichip module using paraffin slurry (파라핀 슬러리를 사용한 다칩모듈의 냉각특성)

  • Jo, Geum-Nam;Choe, Min-Gu
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.6
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    • pp.888-898
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    • 1998
  • The present study investigated the effects of the experimental parameters on the cooling characteristics of the multichip module cooled by the indirect liquid cooling method using water and paraffin slurry. The experimental parameters are mass fraction of 2.5 ~ 7.5% for paraffin slurry, heat flux of 10 ~ 40 W/cm$^{2}$ for the simulated VLSI chips and Reynolds numbers of 5,300 ~ 15,900. The apparatus consisted of test section, paraffin slurry maker, pump, constant temperature baths, flowmeter, etc. The test section made of in-line, four-row array of 12 heat sources for simulating 4 * 3 multichip module which was flush mounted on the top wall of a horizontal rectangular channel with the aspect ratio of 0.2. The inlet temperature was 20 deg. C for all experiments. The size of paraffin slurry was constant as 10 ~ 40 .mu.m befor and after the experiment. The chip surface temperatures for paraffin slurry with the mass fraction of 7.5% showed lower by 16 deg. C than those for water when the heat flux is 40 W/cm$^{2}$. The local heat transfer coefficients for the paraffin slurry with the mass fraction of 7.5% were larger by 17 ~ 25% than those for water at the first and the fourth row. The local heat transfer coefficients reached to a row-number-independent, thermally fully developed value approximately after the third row. The local Nusselt numbers at the fourth row for paraffin slurry with the mass fraction of 7.5% were larger by 23 ~ 29% than those for water.