• Title/Summary/Keyword: pressure housing

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FEM/BEM Modeling of the Top Cap of Scroll Compressors for Analysis of Noise Radiation (스크롤 압축기 상부 캡의 방사 소음 해석을 위한 유한 요소/경계 요소 모델링)

  • Ahn, Jae-Hong;Song, Jae-Soo;Kim, Sung-Won
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.346-350
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    • 2000
  • In scroll compressors, there are two major noise sources. Sturctural path: excitation of the compressor housing by unbalance forces and forces generated by compression cycle. Gas cavity path: excitation of top cap by discharge gas pulsation. In this study, in order to analyze the radiated noise generated by the discharge gas pulsation, FEM/BEM model of the top cap is established. Measured pressure of discharge pulsation is introduced in the FEM model as the excitation and vibration response is calculated. Radiated sound pressure is then obtained by BEM method based on this vibration response. Results are compared with the measured data. It is shown that the trend of the noise radiation can be predicted in this approadch.

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COMPUTATIONAL FLUID DYNAMICS ANALYSIS OF THE CANADIAN DEUTERIUM URANIUM MODERATOR TESTS AT THE STERN LABORATORIES INC.

  • KIM, HYOUNG TAE;CHANG, SE-MYONG
    • Nuclear Engineering and Technology
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    • v.47 no.3
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    • pp.284-292
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    • 2015
  • A numerical calculation with the commercial computational fluid dynamics code CFX-14.0 was conducted for a test facility simulating the Canadian deuterium uranium moderator thermal-hydraulic. Two kinds of moderator thermal-hydraulic tests at Stern Laboratories Inc. were performed in the full geometric configuration of the Canadian deuterium uranium moderator circulating vessel, which is called a calandria tank, housing a matrix of horizontal rod bundles simulating calandria tubes. The first of these tests is the pressure drop measurement of a cross flow in the horizontal rod bundles. The other is the local temperature measurement on the cross section of the horizontal cylinder vessel simulating the calandria system. In the present study, the full geometric details of the calandria tank are incorporated in the grid generation of the computational domain to which the boundary conditions for each experiment are applied. The numerical solutions are reviewed and compared with the available test data.

A Study on the Strength Variation According to the Air Pressure Using the Independent Bubble Type Foaming Agent (독립기포형태 기포제를 활용한 기압에 따른 강도 변화에 대한 논문)

  • You, Nam Gyu;Hong, Sang Hun;Seo, Eun-Seok;Kim, Han-Nah;Kim, Bong Joo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2018.11a
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    • pp.19-20
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    • 2018
  • As energy related problems continue to arise, Korea's thermal insulation market for the zero energy homes is also demanding major changes, but there are no realistic countermeasures. Also, interest in inorganic insulation is growing as damage from multifamily housing fire using flammable insulation materials is increasing. On the other hand, many studies have been conducted on lightweight foam concrete, which implies a sufficient possibility as an insulation material by generating a large amount of air bubbles. However, studies of existion bubble concrete are not quantified by the experimental difficulty of using bubbles when compared. Therefore, in this study, the change in strength due to air pressure using a bubble foam, one of the types of air bubbles for the development of light foam concrete.

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Simulation of injection-compression molding for thin and large battery housing

  • Kwon, Young Il;Lim, Eunju;Song, Young Seok
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1451-1457
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    • 2018
  • Injection compression molding (ICM) is an advantageous processing method for producing thin and large polymeric parts in a robust manner. In the current study, we employed the ICM process for an energy-related application, i.e., thin and large polymeric battery case. A mold for manufacturing the battery case was fabricated using injection molding. The filling behavior of molten polymer in the mold cavity was investigated experimentally. To provide an in-depth understanding of the ICM process, ICM and normal injection molding processes were compared numerically. It was found that the ICM had a relatively low filling pressure, which resulted in reduced shrinkage and warpage of the final products. Effect of the parting line gap on the ICM characteristics, such as filling pressure, clamping force, filling time, volumetric shrinkage, and warpage, was analyzed via numerical simulation. The smaller gap in the ICM parting line led to the better dimensional stability in the finished product. The ICM sample using a 0.1 mm gap showed a 76% reduction in the dimensional deflection compared with the normal injection molded part.

Settlement Characteristics of Soft Ground Applying the Suction Drain Method (석션드레인공법을 적용한 연약지반의 침하 특성)

  • Han, Sang-Jae;Yoo, Han-Kyu;Kim, Byung-Il;Kim, Soo-Sam
    • Journal of the Korean Geotechnical Society
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    • v.29 no.3
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    • pp.15-27
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    • 2013
  • A vacuum pressure method has been developed to solve many problems in the conventional surcharge method such as embankments, and its application has increased in the country. Recently, to control target settlements in the field, there have been many studies on the comparison of settlements between vacuum pressure method and surcharge load method in the same conditions. In this study, the settlement characteristics of soil subjected to vacuum pressure and surcharge pressure are discussed. The results indicate that if vacuum pressure is applied to the improvement of soft ground, there will be inward lateral displacement and the vacuum pressure will induce generally less settlement than a surcharge load of the same magnitude. The range of settlement reduction ratio is 0.54~0.67 based on Hooke's law, 0.91 based on field cases, 0.81 based on laboratory oedometer tests, 0.75 based on the theory of elasticity and coefficient of volumetric compressibility and 0.77~0.93 in its recent applications to the thick soft ground.

Experimental investigation on the high frequency flow-induced vibration and pressure drop of cylindrical tube bundle with plate type supporting structures (플레이트형 지지구조체로 지지된 실린더형 관 군의 고주파 유동유발진동 및 압력손실에 대한 실험적 고찰)

  • Lee, Kang-Hee;Kim, Hyung-Kyu;Yoon, Kyung-Ho;Eom, Kyong-Bo;Kim, Jin-Sun;Suh, Jung-Min
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1367-1372
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    • 2008
  • A plate type supporting structure of a tube bundle in axial flow generates a certain band of a high frequency periodic excitation of a vortex shedding and/or a flow separation due to sharp edge of the plate thickness and a severe pressure drop due to a cross-sectional area of the supports. With a design consideration of the low vibration and a small flow resistance, the analysis method is uniquely confined to an experimental approach because a complex geometry of a cylindrical tube bundle and/or physical phenomena related to the fluid-structure interaction of tube bundle in a flow impede a theoretical or a numerical approach. A 5x5 cylindrical tube bundle with 5 supports which were discretely located along the bundle's axis was tested in the FIVPET hydraulic test loop for a design evaluation and an analysis perspectives. A high frequency flow-induced vibration of the supporting structures of the cylindrical tube bundle was measured at a outer surface of a supporting structure through a transparent flow housing by the laser dopper vibrometer. Pressure drop in-between three measurement distances was measured by the differential pressure transmitter. High frequency vibration and pressure drop fairly depends on the geometric design of supporting structure. So, these two parameters would be used as a qualitative design variables for design evaluation and analysis.

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A Study for Numerical Analysis of Flow Variation on Low Pressure Fuel Pump Fluid using Excavator Engine (굴삭기 엔진용 저압연료펌프 유체의 유동변화에 대한 수치해석적 연구)

  • Lee, IL Kwon;Kim, Seung Chul
    • Journal of the Korean Institute of Gas
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    • v.19 no.6
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    • pp.47-53
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    • 2015
  • This paper is to study applying for numerical analysis method for flow field, velocity and pressure of fuel on the low pressure pump using excavator. The pressure distribution of fuel pump certified the linear variation according to rotation angle of rotor. Especially, it knew the fact that the pressure in rotation angle $40^{\circ}$ appeared high outlet and low inlet of fuel pump. Also, this range angle can seek the fact that the leakage flow and velocity are the most increasing. And the more rotor rotation of fuel pump, the more mean outlet flow rate increased in linear. Whenever the gap size decrease with rotor and housing, the discharge flow rate could seek the approaching 0.0712kg/s that consider with theory discharge flow rate calculated from displacement between rotor gear and idle gear.

A Study on the Safety Improvement of City Gas Pressure Regulators in Apartment Housing (공동주택 등에 설치하는 도시가스 압력조정기의 안전성 향상에 관한 연구)

  • Youngman Yun;Yongchai Kwon;Kyungho Kim;Jihyun Jang
    • Journal of the Korean Institute of Gas
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    • v.27 no.2
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    • pp.86-94
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    • 2023
  • This study was conducted with the purpose of preparing an alternative to improving the safety of civil pressure regulators installed instead of gas governors to supply city gas to apartment houses. First, problems were derived and solutions were presented by investigating the safety standards and installation status of domestic pressure regulators. In addition, using the DNV Phast-Safeti program, a quantitative risk assessment solution, risks such as gas leakage contained in pressure regulators installed in apartment houses and surrounding gas facilities were evaluated in terms of individual risks and societal risks, and measures were derived to reduce the risks in the installation and management of the pressure regulators.

Spray Behavior and Atomization Characteristics of Air-Assist Type Gasoline Fuel Injector (공기보조형 가솔린 연료 분사기의 분무거동 및 미립화 특성)

  • 노병준;강신재;김원태
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.3
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    • pp.187-197
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    • 1998
  • To investigate the spray behavior and atomization characteristics using an air-assist injector, spray visualization and PDPA measurements were carried out under the various assisted air pressures and the fixed fuel pressure. The air assist pintle type injector employed in this study is consisted of the air assist adaptor and an injector housing using the gasoline fuel and air as the working fluids. As results, increasing pressure of assisted air, the growth of spray tip penetration is gradually reduced at the end of spray and spray angle is steadily increased at the main spray region except from the early spray. For the air assist pressure of 25㎪ in a spray downstream, it is doncluded that droplet size distribution shows the peak of 10${\mu}{\textrm}{m}$ and most of the droplet sizes are less than 50${\mu}{\textrm}{m}$. Also, the air-assist injector extremely improves fuel atomization in order to produce much finer droplets, it shows that approximately, in this case, 50% decreade of SMD than without air assit.

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A Study on the Calibration Method for Dynamic Shock Sensor Using Hopkinson Pressure Bar System (홉킨슨 압력봉(Hopkinson pressure bar)을 이용한 동적 충격센서 보정기술 연구)

  • Oh, Se-Wook;Min, Gyeong-Jo;Cho, Sang-Ho
    • Explosives and Blasting
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    • v.38 no.1
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    • pp.23-29
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    • 2020
  • The measurement technique with dynamic shock sensor was widely used in academic experiment for blasting and impact. However, most of dynamic sensors are expensive so that it needs to be protected by external housing structures or damping devices. In this study, the calibration method for dynamic shock sensor under the distortion by external structures. Hopkinson pressure bar system was adopted to measure the input acceleration to the sensor, and it was compared to the acceleration measured by accelerometer with customized damping device. Consequently, it is conclued that this method can be useful to calibrate the dynamic shock sensor under the linear distortion.