• Title/Summary/Keyword: Fluid Measure

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Performance evaluation of bubble pump used on solar water heating system

  • Xuesong, Li;Park, Gi-Tae;Kim, Pil-Hwan;Chung, Han-Shik;Jeong, Hyo-Min
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.416-422
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    • 2007
  • The application analysis of bubble pump on the domestic solar water heater system is presented. The system investigated in this study is a passive device, self pumping and self regulating. It was test to use the bubble pump on solar water heater system. The test experiment has been taken on the existed vacuum tube about the efficiency, working fluid temperature and pressure and circulated power. In order to check the working temperature and working pressure effectively, the bubble pump was test separated from the solar water heater. The equipment consists of the bubble pump, heater and heat exchanger. The main structure of bubble pump was design depend on the character of two phase flow. The complete system was instrumented to measure pressures, temperatures and their relationship with the solar radiation intensity. The theory analysis of design bubble pump has been given and the experiment result analysis has been included in the paper.

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Thermal Conductivity measurement of Binary Nanofluids by the Transient Hot-wire Method (비정상 열선법을 이용한 이성분 나노유체의 열전도도 측정)

  • Cho, Chang-Hwan;Sul, Hea-Youn;Koo, June-Mo;Kang, Yong-Tae
    • Proceedings of the SAREK Conference
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    • 2008.11a
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    • pp.165-169
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    • 2008
  • Binary nanofluids(Binary mixture + nanoparticles) have been extensively paid attention for application in absorption system as a new working fluid. Thermal property evaluation of the new refrigerants is inevitable to apply them for actual system. The objectives of this paper are to measure the thermal conductivity of the binary nanofluids by the transient hot-wire method, and to assess the application possibility of the binary nanofluids for absorption system. It was found that the thermal conductivity of the binary nanofluids ($H_2O/LiBrAl_2O_3$) increased with increasing the concentration of the nanoparticles ($Al_2O_3$) and enhanced up to 27% at 0.1 vol % of the nanoparticles.

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An Experimental Study on the Pumping Characteristics of Diffuser-Nozzle Based Thermopneumatic Micropumps with Different Input Voltages and Frequencies (디퓨져와 노즐을 이용한 열공압형 마이크로 펌프의 입력 전압과 주파수에 따른 펌핑 특성에 관한 실험적 연구)

  • Jeong, Jin;Chae, Hee-Moon;Kim, Chang-Nyung
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.19 no.9
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    • pp.654-661
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    • 2007
  • This study has been conducted to investigate the pumping characteristics of diffuser-nozzle based thermopneumatic micropumps with different input voltages and frequencies. In this study, the displacements of the membrane have been obtained changing the input voltage and frequency in load-free state because it is very difficult to measure the displacement of the membrane in an actual load state. It has been found that the amplitude of the membrane displacement increases as the input voltage increases. The pressure head of the thermopneumatic micropump increases almost linearly over some range of the input voltage and decreases almost linearly as the frequency increases. Also, the results show that the thermopneumatic micropump can pump the fluid over a certain input voltage. This study can be utilized as basic data for design and evaluation of thermopneumatic micropumps.

Experimental Study on the Opening Characteristics for Swing Check Valves (스윙형 역지 밸브의 열림 특성에 관한 실험적 연구)

  • Song, Seok-Yoon;Kim, Yang-Seok;Park, Sung-Keun;Hong, Sung-Yull
    • 유체기계공업학회:학술대회논문집
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    • 2003.12a
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    • pp.555-561
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    • 2003
  • The experimental apparatus is designed and installed to measure the disc positions with flow velocity, $V_{open}\;and\;V_{min}$ for 3 inch and 6 inch swing check valves. The minimum flow velocity necessary to just open the disc at a full open position is referred to as $V_{open}\;and\;V_{min}$ is defined as the minimum velocity to fully open the disc and hold it without motion. In the experiments, $V_{min}$ is determined as the minimum flow velocity at which the back stop load begins to increase after the disc is idly opened or the oscillation level of disc is reduced below $1^{\circ}$. The results show that the $V_{min}$ velocities for 3 inch and 6 inch swing check valves are about 15.6% and 4.8% higher than the $V_{open}$ velocities, respectively. Although the experiments were done with the stable uniform flow, additional experiments will be performed to determine the effects of the upstream disturbances.

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Development of Design Formulas for Pipe Loops Used in Ships Considering the Structural Characteristics of Curved Portions (곡선부의 구조 특성을 고려한 선박용 파이프 루프 설계식 개발)

  • Park, Chi-Mo;Bae, Byoung-Il
    • Journal of Ocean Engineering and Technology
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    • v.26 no.5
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    • pp.87-93
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    • 2012
  • Many longitudinally-arranged pipes in ships are equipped with loops as a measure to reduce stresses caused by displacement loads conveyed from the hull girder bending and/or thermal loads of carried fluid of non-ambient temperature. But as the loops have some negative effects such as causing extra manufacturing cost and occupying extra space, the number and the dimensions of the loops need to be minimized. In the meanwhile, a design formula for pipe loops has been developed by modeling them as a spring element of which stresses and axial stiffness are calculated based on the beam theory. But as the beam theory turns out to be inappropriate to deal with the complex structural behavior in the curved corner portion of the loop, this paper aims at improving the previously developed design formula by adopting correction factors which can allow for the gap between the results of beam theory and a more accurate analysis. This paper adopts a finite element analysis with two-dimensional shell elements with some validation work for it. The paper ends with a sample application of the proposed formulas showing their accuracy and efficiency.

The Volume Measurement of Air Flowing through a Cross-section with PLC Using Trapezoidal Rule Method

  • Calik, Huseyin
    • Journal of Electrical Engineering and Technology
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    • v.8 no.4
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    • pp.872-878
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    • 2013
  • In industrial control systems, flow measurement is a very important issue. It is frequently needed to calculate how much total fluid or gas flows through a cross-section. Flow volume measurement tools use simple sampling or rectangle methods. Actually, flow volume measurement process is an integration process. For this reason, measurement systems using instantaneous sampling technique cause considerably high errors. In order to make more accurate flow measurement, numerical integration methods should be used. Literally, for numerical integration method, Rectangular, Trapezoidal, Simpson, Romberg and Gaussian Quadrature methods are suggested. Among these methods, trapezoidal rule method is quite easy to calculate and is notably more accurate and contains no restrictive conditions. Therefore, it is especially convenient for the portable flow volume measurement systems. In this study, the volume measurement of air which is flowing through a cross-section is achieved by using PLC ladder diagram. The measurements are done using two different approaches. Trapezoidal rule method is proposed to measure the flow sensor signal to minimize measurement errors due to the classical sampling method as a different approach. It is concluded that the trapezoidal rule method is more effective than the classical sampling.

Flow Distribution and Pressure Loss in Subchannels of a Wire-Wrapped 37-pin Rod Bundle for a Sodium-Cooled Fast Reactor

  • Chang, Seok-Kyu;Euh, Dong-Jin;Choi, Hae Seob;Kim, Hyungmo;Choi, Sun Rock;Lee, Hyeong-Yeon
    • Nuclear Engineering and Technology
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    • v.48 no.2
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    • pp.376-385
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    • 2016
  • A hexagonally arrayed 37-pin wire-wrapped rod bundle has been chosen to provide the experimental data of the pressure loss and flow rate in subchannels for validating subchannel analysis codes for the sodium-cooled fast reactor core thermal/hydraulic design. The iso-kinetic sampling method has been adopted to measure the flow rate at subchannels, and newly designed sampling probes which preserve the flow area of subchannels have been devised. Experimental tests have been performed at 20-115% of the nominal flow rate and $60^{\circ}C$ (equivalent to Re ~ 37,100) at the inlet of the test rig. The pressure loss data in three measured subchannels were almost identical regardless of the subchannel locations. The flow rate at each type of subchannel was identified and the flow split factors were evaluated from the measured data. The predicted correlations and the computational fluid dynamics results agreed reasonably with the experimental data.

Study on magnetorheological damper stiffness shift

  • Jafarkarimi, Mohammad H.;Ghorbanirezaei, Shahryar;Hojjat, Yousef;Sabermand, Vahid
    • Smart Structures and Systems
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    • v.25 no.3
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    • pp.279-284
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    • 2020
  • Electrical current is usually used to change the damping force of Magnetorheological Dampers (MRDs). However, changing the electrical current could shift the stiffness of the system, the phenomenon that was not considered carefully. This study aims to evaluate this shift. A typical MRD was designed, optimized, and fabricated to do some accurate and detailed experimental tests to examine the stiffness variation. The damper is equipped with a circulating system to prevent the deposition of particles when it is at rest. Besides that, a vibration setup was developed for the experimental study. It is capable of generating vibration with either constant frequency or frequency sweep and measure the amplitude of vibration. The damper was tested by the vibrating setup, and it was concluded that with a change in electrical current from 0 to 1.4 A, resonant frequency would change from 13.8 Hz to 16 Hz. Considering the unchanging mass of 85.1 kg, the change in resonant frequency translates as a shift in stiffness, which changes from 640 kN/m to 860 kN/m.

The Study on the Physicochemical Properties of Fluid under High Pressure (1). Effects of Pressure and Temperature on the Pentamethyl Benzene-Iodine Charge Transfer Complex in n-HexaneⅠ

  • Kim, Jeong-Rim;Kwun, Oh-Cheun
    • Bulletin of the Korean Chemical Society
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    • v.6 no.2
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    • pp.74-79
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    • 1985
  • The stabilities of the charge transfer complexes of pentamethyl benzene with iodine in n-hexane have been investigated by UV-spectrophotometric measurements at 25, 40 and 60$^{\circ}C$ up to 1600 bars. The equilibrium constant of the complex formation was increased with pressure while being decreased with temperature raising. Changes of volume, enthalpy, free energy and entropy for the formation of the complexes were obtained from the equilibrium constants. The red-shift at higher pressure, the blue-shift at higher temperature, and the relation between pressure and oscillator strength have been discussed by means of thermodynamic functions. In comparison with the results in the previous studies, the absolute values of ${\Delta}$V at each temperature were increased with the number of methyl groups of polymethyl benzene. However, it can be seen that both ${\Delta}$H and ${\Delta}$S show extreme behaviors in durene near atmospheric pressure but they are negatively increased with the number of methyl groups near 1600 bar. This order of the thermodynamic parameters may be a measure of the relative basicities of polymethyl benzenes toward iodine under each pressure, and these phenomena are explained in terms of a positive inductive effect and a steric hindrance effect of the polymethyl benzene molecule.

Measurement of Velocity Field Change around Stern of LNG Carrier Double Body Model by Propeller (프로펠러에 의한 LNG 운반선 이중모형 선미의 속도변화 계측)

  • Kim, Byong-June;Choi, Soon-Ho;Kim, Hyoung-Tae;Van, Suak-Ho
    • Journal of the Society of Naval Architects of Korea
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    • v.42 no.5 s.143
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    • pp.448-457
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    • 2005
  • The experiment was performed at the large wind tunnel of the Chungnam National University to measure the velocity distribution around the stern of a Liquefied Natural Gas Carrier model. The data, mean velocity vectors of turbulent shear flows at the stern and near-wake including the propeller plane, were obtained by a five-hole Pilot tube for the double body model fixed inside the wind tunnel test section. The present result of the double body model shows a close agreement with the result of the lowing tank experiment performed by the KRISO for the same ship model. The characteristics of the LNG stern flow are discussed based on the measured velocity distribution. The data can be very useful for the validation of some numerical methods in computational fluid dynamics.