• Title/Summary/Keyword: Absorption fluid

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Operating Characteristics of a Bubble Pump for Diffusion-Absorption Refrigerator (확산형 흡수식 냉동기용 기포펌프의 운전특성에 관한 연구)

  • 이현경;김선창;이재헌
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.9
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    • pp.878-887
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    • 2001
  • Experimental investigation has been carried out to examine the operating characteristics of a bubble pump for diffusion absorption refrigerator. The effects of heat input and delivery height on generation rate of refrigerant vapor and circulation rate of solution have been investigated. as a result heat input and delivery height increase, circulation rate of solution increases. And the smaller the tube diameter, the larger the circulation rate of solution. Pumping ratio increases to a critical point and then decrease with the increase of heat input, and it increases with the increase in delivery height. In this paper, Marcus's analytical theory was also examined. It was found that the Marcus\`s analytical theory of a bubble pump was not appropriate for a bubble pump using ammonia aqueous solution as a working fluid.

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Characteristics of Absorption Heat Transfer on Micro-Scale Hatched Tubes with Different Surface Roughness (미소해칭 전열관의 표면거칠기에 따른 흡수열전달 특성)

  • 조현철;김춘동;김익생;박찬우;강용태
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.8
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    • pp.641-647
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    • 2002
  • Objectives of this paper are to investigate the effect of roughness of micro-hatching tubes on the absorption performance and to develop on experimental correlation of Nusselt as a function of the roughness. Three different micro-scale hatched tubes and a bare tube were tested in the present experiment. $H_{2}O/LiBr$ solution is used as working fluid. It was found that absorption performance of micro-scale hatched tubes were improved upto 2 times with an error band of ${\pm}25%$ compared with the bare tube. An experimental correlation of Nusselt was developed as a function of the roughness.

Analysis of Thermodynamic Design Data for Heating of Double - Effect Solar Absorption System using LiBr - water and Ethylene Glycol Mixture (에틸렌글리콜 혼합액을 사용하고, 태양열을 보조열원으로 하는 이중효용 흡수식 시스템의 난방 특성해석)

  • Won, S.H.
    • Journal of the Korean Solar Energy Society
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    • v.22 no.4
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    • pp.51-61
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    • 2002
  • Analysis of thermodynamic design data of double effect solar absorption heat pump system for heating has been done to find the property of Libr-water + ethylene Glycol mixture for working fluid by computer simulation. Derived thermodynamic design data. enthalpy based coefficient of performance and flow ratio for possible combinations of operating temperature for water - LiBr and Ethylene Glycol mixture (H2O: CHO ratio 10:1 by mole) by computer simulation. The obtained results, COP and mass flow ratio of the water-lithium bromide-ethylene glycol system, are compared with data for the water-Libr pair solution.

Numerical Modeling of a Rectangular Type Inductively Coupled Plasma System (사각형 유도 결합 플라즈마 시스템의 수치 모델링)

  • Joo, Jung-Hoon
    • Journal of the Korean institute of surface engineering
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    • v.45 no.4
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    • pp.174-180
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    • 2012
  • Low pressure inductively coupled plasma characteristics of argon and oxygen are numerically simulated for a 400 mm rectangular type system with a plasma fluid model. The results showed lower power absorption profile at the corner than a circular one in a 13.56 MHz driven 1.5 turn antenna system with a drift-diffusion and quasi-neutrality assumption. Ions controlled by electric field are more non-uniform than metastables and the power absorption profile of oxygen plasma is affected by horizontal gas flow pattern to show 25% lower power absorption at the pumping flange side. Oxygen negative ions which are generated in electron collisional dissociation of oxygen molecules was calculated as 0.1% of oxygen atoms with similar spatial profile.

A CASE REPORT OF MULTIPLE CYSTS IN THE JAWS (다발성 낭종의 증예보고)

  • Park Tae Won;Lee Sang Rae
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.3 no.1
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    • pp.35-38
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    • 1973
  • The authors have interpreted one patient's full mJuth intra-oral films, oblique- lateral film of the left mandible and orthopantomograph which revealed 6 radicular and 1 residual cysts. As a results of interpretation of these serial films, we have drawn following conclusions: 1. Radicular cyst arose from the cell rests contained in an apical granuloma which was sequel to advanced pulpitis due to dental caries. 2. Residual cyst was developed from remaining cell rests after the extraction of a tooth with such a radicular cyst or apical dental granuloma. 3. Cyst grew in size by absorption of fluid into cystic cavity due to difference in osmotic pressure between the cystic fluid and adjacent tissue fluid.

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Fluid-structure interaction simulation of a floating wave energy convertor with water-turbine driven power generation

  • Zullah, Mohammed Asid;Lee, Young-Ho
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.8
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    • pp.710-720
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    • 2016
  • The Floating Wave Energy Convertor (FWEC) mooring design has an important requirement associated with the fact that, for a wave energy converter, the mooring connections may interact with their oscillations, possibly modifying its energy absorption significantly. It is therefore important to investigate what might be the most suitable mooring design according to the converter specifications and take into account the demands placed on the moorings in order to assure their survivability. The objective of this study is to identify a computational fluid dynamics method for investigating the effects of coupling a wave energy device with a mooring system. Using the commercial software ANSYS AQWA and ANSYS FLUENT, a configuration was studied for different displacements from the equilibrium position, load demands on the moorings, and internal fluid motion. These results and findings form a basis for future efforts in computational model development, design refinement, and investigation of station keeping for FWEC units.

Effect of Abrasion and Absorption on the Handle of Nonwovens for disposable diaper (기저귀용 부직포의 촉감에 미치는 마찰과 함수의 영향)

  • 홍경화;강태진;오경화
    • Journal of the Korean Society of Clothing and Textiles
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    • v.28 no.1
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    • pp.112-118
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    • 2004
  • Recently, as the percentage of women employment has been growing, the demand for various facilities and services regarding household duties and infant rearing is increasing and so do the amount of the disposable diaper used. Among the components of disposable diaper, the top sheet contacting with infant skin directly is usually made with nonwoven textiles. Therefore, the mechanical and surface characteristics of the nonwovens used in disposable diaper are important for the skin health of infants. In this study, we have explored the mechanical and surface properties, such as friction coefficient, fluid permeability and strength, of the nonwovens used for disposable diaper top sheet and observed the variation of their properties with abrasion cycles. Nonwoven materials examined in this study are 100% cotton spunlace, 100% tencel spunlace, 100% polypropylene (PP) thermal bonding and 100% PP air through (Thru-air bonded carded web). From the result of KES-F analysis, we've found that 100% PP air through type nonwoven had a low friction coefficient and showed a little change in surface properties as increasing abrasion cycles. Moreover, it revealed superior fluid permeability and quick-drying character. On the other hand, though showing an excellent absorption force, the spun lace type nonwoven made of 100% cotton and 100% tencel displayed relatively low abrasion strength especially in wetting condition.

A Numerical Analysis on the Heat Transfer and Pressure Drop Characteristics of Welding Type Plate Heat Exchangers (용접형 판형열교환기의 열전달 및 압력강하특성에 관한 수치해석)

  • Jeong, Jong-Yun;Nam, Sang-Chul;Kang, Yong-Tae
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.9
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    • pp.676-682
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    • 2008
  • Numerical analysis was carried out to examine the heat transfer and pressure drop characteristics of plate heat exchangers for absorption application using Computational Fluid Dynamics(CFD) technique. A commercial CFD software package, FLUENT was used to predict the characteristics of heat transfer, pressure drop and flow distribution within plate heat exchangers. In this paper, a welded plate heat exchanger with the plate of chevron embossing type was numerically analyzed by controlling mass flow rate, solution concentration, and inlet temperatures. The working fluid is $H_2O$/LiBr solution with the LiBr concentration of 50-60% in mass. The numerical simulation shows reasonably good agreement with the experimental results. Also, the numerical results show that plate of the chevron shape gives better results than plate of the elliptical shape from the view points of heat transfer and pressure drop. These results provide a guideline to apply the welded PHE for the solution heat exchanger of absorption systems.

Simulation of $H_2O/LiBr$ Triple Effect Absorption Systems with a Modified Reverse Flow

  • Jo, Young-Kyong;Kim, Jin-Kyeong;Kang, Yang-Tae
    • International Journal of Air-Conditioning and Refrigeration
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    • v.15 no.3
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    • pp.114-121
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    • 2007
  • In this study, a modified reverse flow type, one of the triple effect absorption cycles, is studied for performance improvement. The cycle simulation is carried out by using EES(Engineering Equation Solver) program for the working fluid of $H_2O/LiBr$ solution. The split-ratios of solution flow rate, UA of each component, pumping mass flow rate of solution are considered as key parameters. The results show that the optimal SRH (split ratio of high side) and SRL (split ratio of low side) values are 0.596 and 0.521, respectively. Under these conditions, the COP is maximized to 2.1. The optimal pumping mass flow rate is selected as 3 kg/s and the corresponding UAEV A is 121 kW/K in the present system. The present simulation results are compared to the other literature results from Kaita's (2002) and Cho's (1998) triple effect absorption systems. The present system has a lower solution temperature and a higher COP than the Kaita's modified reverse flow, and it also gives a higher COP than the Cho's parallel flow by adjusting split ratios.