• Title/Summary/Keyword: rosin size

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Dilutant flow characteristics model of coarse particle suspensions with uniform size distribution

  • Ookawara, Shinichi;Ogawa, Kohei
    • Korea-Australia Rheology Journal
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    • v.15 no.1
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    • pp.35-41
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    • 2003
  • It is expected that particle size distribution of any portion obtained through screening, is of more uniform than that of the original mixture, typically following such as log-normal, Rosin-Rammler distributions and so on. In this study, therefore, a new relation between parameters of the uniform distribution and flow characteristics of the coarse particle suspensions is derived based on the continuous polydisperse model (Ookawara and Ogawa, 2002b), which is derived from the discrete polydisperse model (Ookawara and Ogawa,2002a). The derived model equation predicts a linear increase of viscosity with shear rate, viz., dilutant flow characteristics. Further, the increase of viscosity is expected to be proportional to the square of volume fraction of particles, and to show the linear dependency on density and average diameter of particles. It is also shown that the uniform distribution model includes additional term that expresses the effect of distribution width. For verification of the model, the experimental results of Clarke (1967) are cited as well as in our previous work for the monodisperse model (Ookawara and Ogawa,2000) since most parameters were varied independently in his work. It is suggested that the newly introduced term expands the applicable range compared with the monodisperse model.

A Study on Droplet Distribution of Bio Diesel Fuels Using Immersion Sampling Method (액침법에 의한 바이오디젤유의 액적분포에 관한 연구)

  • Kim, M.S.;Doh, H.C.;Koh, D.K.;Ahn, S.K.
    • Journal of Power System Engineering
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    • v.10 no.4
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    • pp.5-10
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    • 2006
  • The purpose of this study is to measure the droplet distribution and Sauter mean diameter(SMD) of biodiesel fuel, using the immersion sampling method. This method involves using an optical microscope and a CCD camera, to take an image of the droplets. These images are then measured by using a 'Sigma Scan' processing program. The results of the above experiment are summarized as followed ; (1) There can be as much as a 10% error rate when measuring the diameter of these droplets, using the image processing method and the naked eye. (2) The result of droplet size distribution test, TVO(transesterified vegetable oil) big size droplet distribution were increased at ambient pressure $6kg/cm^2$. (3) When ambient pressure increased $6kg/cm^2$ above, SMD variation of TVO and UVO(used vegetable oil) 30 are small. (4) On Rosin-Rammler analysis, droplets size distribution of UVO(used vegetable oil) 30 uniform more than TVO 20 on ambient pressure $1kg/cm^2$.

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An Experimental Study on Droplet Size according to Discharge Coefficient of Sprinkler Head (스프링클러 헤드의 방수상수에 따른 물방울 크기에 관한 실험적 연구)

  • Hur, Min Noung;Shin, Changsub
    • Journal of the Korean Society of Safety
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    • v.32 no.4
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    • pp.16-21
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    • 2017
  • The sprinkler system is a basic fire extinguishing system that uses water as an extinguishing agent. In order to evaluate the fire extinguishing performance of the sprinkler system, information such as the discharge angle, discharge speed, discharge pressure, flow rate, and water droplet size of the installed head are required. However, there is a lack of research on droplets size compared to other requirements. In this study, to evaluate the extinguishing characteristics of sprinkler system, the droplet size distribution was measured for various types of sprinkler heads actually used. The size of the droplet was measured using laser diffraction method. The 50% cumulative volume distribution ($D_{v50}$) according to discharge coefficient(K factor) was $540{\mu}m{\sim}695{\mu}m$ for K50, $542{\mu}m{\sim}1,192{\mu}m$ for K80, $980{\mu}m{\sim}1,223{\mu}m$ for K115 and $1,188{\mu}m{\sim}1,234{\mu}m$ for K202. Based on the measured results, the vaeiance of the droplet particle distribution and the distribution ($D_{v50}$) according to discharge coefficient(K factor) was $540{\mu}m{\sim}695{\mu}m$ for K50, $542{\mu}m{\sim}1,192{\mu}m$ for K80, $980{\mu}m{\sim}1,223{\mu}m$ for K115 and $1,188{\mu}m{\sim}1,234{\mu}m$ for K202. Based on the measured results, the vaeiance of the droplet particle distribution and the Rosin-Rammler index value are presented. As a result of the fire simulation with FDS, it was confirmed that the performance difference occurs according to the water droplet size distribution even when the same amount of water is used. Therefore, the extinguishing performance of the sprinkler system should be evaluated considering the droplet size distribution according to the sprinkler head type.

Prediction of Pressure Drop in Venturi Scrubber Using the Eulerian - Lagrangian Method (오일러-라그랑지 방법을 이용한 벤튜리 스크라버의 압력강하 계산)

  • Pak S, I.;Moon Y. W.;Chang K. S.
    • 한국전산유체공학회:학술대회논문집
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    • 2004.03a
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    • pp.190-195
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    • 2004
  • The pressure drop in a Venturi Scrubber is predicted using the Eulerian-Lagrangian Method, which is one of the numerical methods to solve the dispersed two-phase flow. KIVA-3V Code is modified to solve the coupled gas-liquid two-phase flow field. The liquid is assumed to be injected through the nozzles with the Rosin-Rammler drop size distribution. The computational results shows good agreement with the experimental data.

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Comparison between heavy oil combustion test and numerical analysis of combustion phenomena subject to changes in injection characteristics (분무특성에 따른 중유연소 수치해석의 결과와 실험과의 비교)

  • Lee, S.S.;Kim, H.J;Kim, J.J.;Choi, K.S.
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.338-343
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    • 2003
  • Computations were performed to investigate the spray characteristics of the twin fluid nozzle in three stage heavy-oil combustion burner. The burner geometry and flow conditions were provided by a burner company. The goal of the study is to estimate mean droplet size, initial velocity and spread factor of the nozzle through comparison between experiments and numerical analyses. Air stage ratio is 2:4:4 by mass, and O2 in exhaust gas is about 4 % by volume. Here, the agreement between the experiment and numerical analyses is evaluated by NOx generation. Spray characteristics will be linearly interpolated between fuel consumption rate l20L/h and 240 L/h.

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An Experimental Study on the Drop Distribution and the Combustion Characteristics with different Bluff-body Geometries (보염기 형상에 따른 연료액적분포와 연소특성에 관한 실험적 연구)

  • Hwang, S.H.;Kim, D.J.
    • Journal of ILASS-Korea
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    • v.9 no.2
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    • pp.1-8
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    • 2004
  • This work was performed to investigate the distribution of the fuel droplet size around the bluff-body and the combustion characteristics. The geometry of the bluff-body influenced the spray shape and the combustion characteristics. Diameters of the bluff-body in this experiment are 6, 8, and 10 mm and the impingement $angles({\theta})\;are\;30^{\circ},\;60^{\circ},\;and\;90^{\circ}$. The measurement points were at the distances of 20 and 30 mm axially from the nozzle. The SMD and Rosin-Rammler distribution was acquired by image processing technique (PMAS), and the mean temperatures were measured by thermocouple. The results obtained are as follows; In the condition of ${\theta}=60^{\circ}$, the values of SMD are not greatly varied compared to the other conditions. As the impingement angle of bluff-body was increased, the high temperature region was wider along radial direction. When the air-fuel ratio was increased, the CO concentration was decreased.

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Total sizing system (총 사이징 시스템)

  • Proverb, Robert J.;Pawlowska, Lucyna;Komarowska, Kasia;Garro, Gina;Dilts, Kimberly
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • 2004.07a
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    • pp.19-42
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    • 2004
  • Sizing properties in paper are generally developed through the application of both internal and surface sizes. Rosin, wax, and synthetic sizes including ASA, AKD, and stearic anhydride are and have been used to provide wet-end sizing to paper. In many cases, the use of some of these sizes leads to runnability problems that are inherent in the wet-end operation. Variability in furnish, fines, broke, filler, water chemistry, conductivity, and pH control impacts the wet-end operation. Size press chemicals including starch and polymers such as styrene-acrylic, styrene-maleic, and styrene acrylate emulsions are used in conjunction with internal sizes to improve the paper surface for printing and strength properties, porosity, and opacity improvement. This paper will discuss results from a new, proprietary formulation and process that allows application of sizing chemistry more totally at the size press with reduced emphasis on wet end sizing. Runnability issues are thus minimized at the wet-end, chemical usage is more efficient, and significant cost savings can be realized. Case histories will be presented illustrating the advantages of this new application in commercial trials.

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Effects of Limestone Powder on the Fluidity of Ordinary Portland Cement Paste (보통 포틀랜드 시멘트 페이스트의 유동특성에 미치는 석회석 미분말의 영향)

  • Lee, Seung-Heun;Park, Jeong-Soo;Lee, Jeong-In;Cho, Jae-Woo
    • Journal of the Korean Ceramic Society
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    • v.50 no.2
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    • pp.149-156
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    • 2013
  • This study examines the effects of limestone's factors on the fluidity of cement paste when of up to 15%. As the substitution ratio of limestone powder increases, the fluidity of the paste is also improved; however, it has no correlation to the $CaCO_3$ content of the limestone, fineness of the limestone, and fluidity of the pastes. Regardless of clay content of the limestone, it showed a similar mini-slump, so there was no correlation between the clay content and the fluidity of the paste. Also, the total organic carbon content of the limestone and the fluidity of the paste showed no correlation. Regardless of the limestone's grade or fineness, n value of powder gained by using the Rosin-Rammler distribution function showed that the fluidity of the paste increased as the n value reduced. It was also shown that particle size distribution of ordinary Portland cement with limestone powder had a major effect on the fluidity of the paste.

Studies on Oyster Mushroom (Pleurotus ostreatus) Packed in Various Environmental Friendly Trays (환경 친화적 포장재를 이용한 느타리버섯의 저장성 연구)

  • 신동화;안용선;강진하;오승원
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.29 no.1
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    • pp.85-92
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    • 2000
  • This study was carried out to storage of Pleurotus ostreatus packed in various trays made by different matrials-expanded polystyrene (EPS), rice straw pulp(RP), and RP trays coated with starch, carboxyl methyl cellulose (CMC), polyacrylamide (PAM), alkylketen dimer (AKD), rosin size (RS) and polyethylene glycol (PEG) at 8~1$0^{\circ}C$ and 70~80% relative hymidity for 6 days. At 6 days storage, weight increase of RP and CMC tray was lower (p<0.05) than those of others and the weight of oyster mushroom packed in RP, CMC and AKD tray decreased lower(p<0.05) than those of others. Carbon dioxide contents in trays were increased from 0.5% to 5.5%~8.6% within 1 day storage. Oxygen contents in trays were sharply decreased from 20% to 0.8%~8.2% within 1 day storage. Lightness of oyster mushroom increased all trays. Off flavor appeared stronly in oyster mushroom packed in EPS, AKD and PEG during storage, but was not detected in mushroom packed in starch and CMC until 4 days storage.

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Reflow Behavior and Board Level BGA Solder Joint Properties of Epoxy Curable No-clean SAC305 Solder Paste (에폭시 경화형 무세정 SAC305 솔더 페이스트의 리플로우 공정성과 보드레벨 BGA 솔더 접합부 특성)

  • Choi, Han;Lee, So-Jeong;Ko, Yong-Ho;Bang, Jung-Hwan;Kim, Jun-Ki
    • Journal of the Microelectronics and Packaging Society
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    • v.22 no.1
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    • pp.69-74
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    • 2015
  • With difficulties during the cleaning of reflow flux residues due to the decrease of the part size and interconnection pitch in the advanced electronic devices, the need for the no-clean solder paste is increasing. In this study, an epoxy curable solder paste was made with SAC305 solder powder and the curable flux of which the main ingredient is epoxy resin and its reflow solderability, flux residue corrosivity and solder joint mechanical properties was investigated with comparison to the commercial rosin type solder paste. The fillet shape of the cured product around the reflowed solder joint revealed that the curing reaction occurred following the fluxing reaction and solder joint formation. The copper plate solderability test result also revealed that the wettability of the epoxy curable solder paste was comparable to those of the commercial rosin type solder pastes. In the highly accelerated temperature and humidity test, the cured product residue of the curable solder paste showed no corrosion of copper plate. From FT-IR analysis, it was considered to be resulted from the formation of tight bond through epoxy curing reaction. Ball shear, ball pull and die shear tests revealed that the adhesive bonding was formed with the solder surface and the increase of die shear strength of about 15~40% was achieved. It was considered that the epoxy curable solder paste could contribute to the improvement of the package reliability as well as the removal of the flux residue cleaning process.