• 제목/요약/키워드: Solid height

검색결과 272건 처리시간 0.032초

탱크로리에서의 유체-고체 연성거동특성연구 (A Study on the characteristics of fluid-solid coupling behavior of the tanker-lorry)

  • 김현수;이영신
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 추계학술대회논문집
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    • pp.1097-1100
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    • 2004
  • In this study the fluid-solid coupling(sloshing) behavior of the tanker-lorry during turning are investigated numerically. The ALE numerical method is used as sloshing analysis algorithm and numerical simulation is conducted for the various fluid filling height 25%, 50% and 75%. The forces for radial and vertical direction are calculated and compared for various fluid-filling heights. From the analysis results, in case of 25% filling, the sloshing effect is the most highest.

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높은이랑재배에 의한 하우스 밀감의 품질향상 (Effects of Ridge-up Bed Cultivation on the Fruit Quality of Satsuma Mandarin ('Miyagawa Wase') in a Plastic Film House)

  • 김용호;김창명;정순경
    • 원예과학기술지
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    • 제18권5호
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    • pp.599-604
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    • 2000
  • 이랑높이가 하우스밀감의 품질에 미치는 영향을 구명하고자 이랑높이를 0, 20cm, 40cm, 60cm로 하여 궁천조생과 흥진조생을 공시하고, 토양수분 및 품질의 변화를 조사하였다. 하우스밀감의 고품질 생산에 필요한 토심 30cm에서의 토양수분포테셜이 -1.4Mpa이 되기까지는 평휴에서 100일 이상, 20cm에서 100일, 40cm에서 60일, 60cm에서 30일이 소요되었다. 착색도 a는 이랑높이가 높아질수록 증가되어 평휴에 비해 60cm 이랑에서 11이나 증가되어 이랑높이에 따른 착색 촉진효과가 현저하였으며, a/b도 이와 유사한 경향을 나타내었으나, 품종간에는 차이를 인정할 수 없었다. 포도당과 과당으로 조성된 환원당은 이랑이 높아질수록 증가되는 경향이 뚜렷하였고 포도당에 비해 과당 함량이 많은 편이었다. 자당은 환원당과 유사한 경향을 나타내었으나 환원당에 비해서는 낮은 편이었으며, 품종간에는 이랑높이에 따른 차이가 없었다. 실제적으로 하우스밀감의 품질을 대표하는 당도는 평휴, 20, 40, 60cm 이랑에서 각각 11.4, 12.1, 12.5, $12.8^{\circ}Brix$로 평휴에 비해 60cm 이랑에서 $1.4^{\circ}Brix$나 증가되는 효과를 가져왔으며, 산도도 이와 유사한 경향을 보였다.

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Hydrodynamic coupling distance between a falling sphere and downstream wall

  • Lin, Cheng-Chuan;Huang, Hung-Tien;Yang, Fu-Ling
    • Coupled systems mechanics
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    • 제7권4호
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    • pp.407-420
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    • 2018
  • In solid-liquid two phase flow, the knowledge of how descending solid particles affected by the presence of downstream wall is important. This work studies at what interstitial distance the velocity of a vertically descending sphere is affected by a downstream wall as a consequence of wall-modified hydrodynamic forces through a validated dynamic model. This interstitial distance-the hydrodynamic coupling distance ${\delta}_c-is$ found to decay monotonically with the approach Stokes number St which compares the particle inertia to viscous drag characterized by the quasi-steady Stokes' drag. The scaling relation ${\delta}_c-St-1$ decays monotonically as literature below the value of St equal to 10. However, the faster diminishing rate is found above the threshold value from St=10-40. Furthermore, an empirical relation of ${\delta}_c-St$ shows dependence on the drop height which clearly indicates the non-negligible effect of unsteady hydrodynamic force components, namely the added mass force and the history force. Finally, we attempt a fitting relation which embedded the particle acceleration effect in the dependence of fitting constants on the diameter-scaled drop height.

가변금형을 이용한 스트레치 성형장치 개발 (Development of Stretch Forming Apparatus using Flexible Die)

  • 서영호;허성찬;박중원;구태완;송우진;김정;강범수
    • 소성∙가공
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    • 제19권1호
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    • pp.17-24
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    • 2010
  • A stretch forming method has been widely used in sheet metal forming process. Especially, this process has been adopted in aircraft and high-speed train industries for skin structure forming having a variety of curvature. Until now, solid dies, which are designed with respect to the specific shapes and manufactured as a single piece, have been usually applied to stretch forming process. Therefore, a great number of solid dies has to be developed according to the shapes of the curved skin structure. Accordingly, a flexible die is proposed in this study. It replaces the conventional solid dies with a set of height adjustable punch array. A usefulness of the flexible die is verified through a formability comparison with the solid die using finite element method considering an elastic recovery and the stretch forming apparatus with the flexible die is developed.

인산가용화 사상균 Penicillium sp. PS-113의 고체배양 (Solid Culture of Phosphate-solubilizing Fungus, Penicillium sp. PS-113)

  • 강선철;최명철
    • 한국미생물·생명공학회지
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    • 제27권1호
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    • pp.1-7
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    • 1999
  • A fungus, Penicillium sp. PS-113, isolated from soil showed the high phosphate-solubilizing activity in patato dextrose broth-rock phosphate to produce free phosphates to the culture broth with the concentrations of 585 ppm against rock phosphate. In this medium, the optimum temperature and initial pH to solubilize rock phosphate were 30$^{\circ}C$ and pH 7.5, respectively. In order to make the mass production of the conidia from this fungus, we cultured in on various solid-based media like barley, corn, wheat, rice, rice bran, and compost. As a result, the fungus highly produced conidia ranging from 2.1 to $5.1{\times}10_9$ conidia/g${\cdot}$media on these solid media except compost-based medium, which was 0 times less than others. Effects of inoculation of the phosphate solubilizing fungus as a biofertilizer were studied in perlite-based pot cropped with Zea mays Suwon 19. Inoculation of Penicillium sp. PS-113 increased in plant height (1.4 times), plant weight (5.2~8.1 times) and root length (1.1~1.2 times) at 60-day cultivation, compared to Hogland solution either without $NH_4H_2PO_4$ or displace $NH_4H_2PO_4$ to powdered rock phosphate, a phosphorus source for plant growth.

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기 - 액 - 고 3상계 교반조내의 고-액간 물질이동 (Solid-Liquid Mass Transfer in Gas-Solid-Liquid 3-Phase System Agitated Vessel)

  • 이영세;加藤禎人;鈴木純一郞
    • 공업화학
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    • 제17권5호
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    • pp.509-516
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    • 2006
  • Rushton turbine, paddle and propeller 임펠러 등 표준적인 임펠러가 부착된 기-액-고 3상교반조에서 고-액간 물질이동계수 $k_L$를 측정하였다. 표준적인 임펠러들에 대한 부유화한계회전수 $N_{js}$는 임펠러 높이와 가스유속에 따라 변했다. 입자부유가 통기에 의존한 Rushton turbine 임펠러의 물질이동계수는 Pgv에만 상관하였다. Rushton turbine, paddle and propeller 임펠러에 대한 물질이동계수 $k_L$은 임펠러의 종류에 의하지 않고 임펠러 위치에 영향을 받았다.

An experimental study on pool sloshing behavior with solid particles

  • Cheng, Songbai;Li, Shuo;Li, Kejia;Zhang, Ting
    • Nuclear Engineering and Technology
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    • 제51권1호
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    • pp.73-83
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    • 2019
  • It is important to clarify the mechanisms of molten-fuel-pool sloshing behavior that might be encountered during a core disruptive accident of sodium-cooled fast reactors. In this study, motivated by acquiring some evidence for understanding the characteristics of this behavior at more realistic conditions, a number of experiments are newly performed by injecting nitrogen gas into a water pool with the accumulation of solid particles. To achieve comprehensive understanding, various parameters including particle bed height, particle size, density, shape, gas pressure along with the gas-injection duration, were employed. It is found that due to the different interaction mechanisms between solid particles and the gas bubble injected, three kinds of regimes, termed respectively as the bubble-impulsion dominant regime, the transitional regime and the bed-inertia dominant regime, could be identified. The performed analyses also suggest that under present conditions, all our experimental parameters employed can have noticeable impact on the regime transition and resultant sloshing intensity (e.g. maximum elevation of water level at pool peripheries). Knowledge and fundamental data from this work will be used for the future verifications of fast reactor severe accident codes in China.

고액분리 통합이론에서 pd의 역할: 간섭침전, 케이크 여과, 압착에서 케이크 두께를 중심으로 (The Role of pd in the Unified Theory on Solid-Liquid Separation: Especially on the Cake Thickness at Hindered Sedimentation, Cake Filtration and Expression)

  • 임성삼;송연민
    • Korean Chemical Engineering Research
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    • 제50권2호
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    • pp.334-342
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    • 2012
  • 새로 개발된 '고액분리 통합이론'의 핵심 개념인 '케이크 첫 입자층이 받는 압력 $p_d$'의 역할을 인식하기 위해, 고압축성 케이크에 대해 다음과 같은 세 가지 고액분리 분야를 새로운 개념으로 분석하였다. 첫째, 침전된 플럭의 케이크 여과에서 여과 대상이 되는 침전 플럭의 두께 계산에서 $p_d$의 역할과, 케이크의 형성 두께 계산에서의 $p_d$의 역할. 둘째, 압착 과정에서의 $p_d$의 역할, 그리고 마지막으로 간섭침전 결과 쌓이는 높이에 미치는 $p_d$의 역할과 간섭침전 과정에서의 $p_d$의 중요성을 보였다. 이로써 고액분리 통합이론의 적용 가능성과, 그에 있어 $p_d$의 중요성을 밝힐 수 있었다. 이 과정을 통하여 케이크 여과, 압착, 간섭침전의 이론적인 새로운 정의가 가능해졌다.

Dynamic response of a base-isolated CRLSS with baffle

  • Cheng, Xuansheng;Liu, Bo;Cao, Liangliang;Yu, Dongpo;Feng, Huan
    • Structural Engineering and Mechanics
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    • 제66권3호
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    • pp.411-421
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    • 2018
  • Although a rubber isolation cushion can reduce the dynamic response of a structure itself, it has little influence on the height of a sloshing wave and even may induce magnification action. Vertical baffles are set into a base-isolated Concrete Rectangular Liquid Storage Structure (CRLSS), and baffles are opened as holes to increase the energy dissipation of the damping. Problems of liquid nonlinear motion caused by baffles are described using the Navier-Stokes equation, and the space model of CRLSS is established considering the Fluid-Solid Interaction (FSI) based on the Finite Element Method (FEM). The dynamic response of an isolated CRLSS with various baffles under an earthquake is analyzed, and the results are compared. The results show that when the baffle number is certain, the greater the number of holes in baffles, the worse the damping effects; when a single baffle with holes is set in juxtaposition and double baffles with holes are formed, although some of the dynamic response will slightly increase, the wallboard strain and the height of the sloshing wave evidently decrease. A configuration with fewer holes in the baffles and a greater number of baffles is more helpful to prevent the occurrence of two failure modes: wallboard leakage and excessive sloshing height.

열처리조건이 두 NASICON 조성의 소결 및 전기적특성에 미치는 영향 (Effects of Heat-treatment Condition on the Characteristics of Sintering and Electrical Behaviors of Two NASICON Compounds)

  • 강희복;조남희;김윤호
    • 한국세라믹학회지
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    • 제34권7호
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    • pp.685-692
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    • 1997
  • Effects of sintering temperature and time on the phase formation, the characteristics of sintering and electrical behaviors of NASICON compounds with Na3Zr2Si2PO12 and Na3.2Zr1.3Si2.2P0.8O10.5 compositions synthesized by solid state reaction were investigated. Maximum relative densities of 96% and 91% were obtained for Na3Zr2Si2PO12 and Na3.2Zr1.3Si2.2P0.8O10.5 compounds, respectively. Complex impedance analysis in a frequency range below 4 MHz was performed to measure the ionic conductivity and migration barrier height of the compounds at RT-30$0^{\circ}C$. The maximum ionic conductivity and the minimum migration barrier height were 0.45 ohm-1cm-1 and 0.07 eV, respectively. The migration barrier height of the high temperature form (space group : R3c) is about 30-40% of that of the low temperature form (space group : C2/c) in two NASICON compounds. Ionic conductivity increases with increasing sinterability, and the presence of glass phase in Na3.2Zr1.3Si2.2P0.8O10.5 compounds lowers significantly ionic conductivity at temperatures above 14$0^{\circ}C$.

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