• Title/Summary/Keyword: Particle size measurement

Search Result 441, Processing Time 0.022 seconds

A study on distribution of drop size and injection rate of air-shroud injector sprays under steady and transient injection condition (정상.과도 분사 조건에서의 에어슈라우드 인젝터 분무의 입경.분사량 분포에 관한 연구)

  • Lee, C.H.
    • Journal of ILASS-Korea
    • /
    • v.9 no.4
    • /
    • pp.17-23
    • /
    • 2004
  • Spray characteristics of a twin-hole air shrouded nonle designed for gasoline injectors was investigated by using laser diffraction particle analyzer (LDPA) and tomography reconstruction- A confined spray chamber which is optically accessible through a pair of glass windows was made to simulate the fuel injection condition in intake manifold of gasoline engine. The measurement was applied to the twin hole injector with and without an air shroud. It demonstrates that for the case with an air shroud, fine atomization is achieved and there exists a large number of fine droplets between the region of the main spray streams, which conforms with the spray visualization. The drop size distribution was investigated as a function of elapse time after fuel injection. The distribution was greatly affected by the measurement position from the injector exit. Also, the spatially resolved spray volume fraction and Sauter Mean Diameter (SMD) from line-of-sight data of the LDPA are tomographically reconstructed by Convolution Fourier transformation under the steady injection condition.

  • PDF

Characteristics of Black Carbon Particles in Ambient Air Using a Single Particle Soot Photometer (SP2) in May 2013, Jeju, Korea (SP2 (Single Particle Soot Photometer)를 이용한 제주도 5월 Black Carbon 특성)

  • Oh, Jun;Park, Jinsoo;Lee, Sanguk;Ahn, Joonyoung;Choi, Jinsoo;Lee, Sangdeok;Lee, Yonghwan;Kim, Hyunjae;Hong, Youdeog;Hong, Jihyung;Kim, Jeongho;Kim, SangWoo;Lee, Gang-Woong
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.31 no.3
    • /
    • pp.255-268
    • /
    • 2015
  • Single particle soot photometer (SP2) is an advanced instrument capable of real-time measurement of concentration, coating thickness, and size distribution of individual BC particle using laser-induced incandescence. So far, there have been insufficient studies examining the real-time characteristics of BC in Korea. In this study, we examined temporal variations in BC concentration and mass size distribution of BC in volume equivalence diameter at a background site of Aewol, Jeju in May. Average concentration and mass median diameter (MMD) of BC particles measured during the study period (06~ 16 May 2013) were $0.69{\pm}0.48{\mu}g/m^3$ and $196{\pm}17nm$, respectively. The BC concentration measured in Aewol was very similar to that observed in the spring of 2012 in Baengnyeong island, and showed diurnal profiles similar to those in other background areas. MMD of BC ranged from 172 to 222 nm. It was found that the mass size distribution of BC varied depending on the location (ground-based), season, types of air masses, and altitude (aircraft-based).

Comparison of the Viscosity of Ceramic Slurries using a Rotational Rheometer and a Vibrational Viscometer (회전형 레오미터와 진동형 점도계를 이용한 세라믹 슬러리의 점도 비교)

  • Ji, Hye;Lim, Hyung Mi;Chang, Young-Wook;Lee, Heesoo
    • Journal of the Korean Ceramic Society
    • /
    • v.49 no.6
    • /
    • pp.542-548
    • /
    • 2012
  • The viscosity of a ceramic slurry depends on the slurry concentration, particle shape and size, hydrodynamic interactions, temperature, shear rate, pre-treatment condition and the method of measurement with the selected equipment. Representative ceramic slurries with low to high viscosity levels are selected from colloidal silica, barium titanate slurry and glass frit paste. Rotational rheometers and vibrational viscometers are used to compare the measured viscosity for various ceramic slurries. The rotational rheometer measured the viscosity according to the change of the shear rate or the rotational speed. On the other hand, the vibrational viscometer measured one point of the viscosity in a fixed vibrational mode. The rotational rheometer allows the measurement of the viscosity of a ceramic paste with a viscosity higher than 100,000 cP, while the vibrational viscometer provides an easy and quick method to measure the viscosity without deformation of the ceramic slurry due to the measurement method. It is necessary to select suitable equipment with which to measure the viscosity depending on the purpose of the measurement.

Measurements of Ultrasound Attenuation Coefficient at Various Suspended Sediment Concentrations (부유물 농도 변화에 따른 초음파 신호의 감쇠계수 측정)

  • Lee, Changil;Choi, Jee Woong
    • The Journal of the Acoustical Society of Korea
    • /
    • v.33 no.1
    • /
    • pp.1-9
    • /
    • 2014
  • Coastal water including estuaries has distinctive environmental characteristics where sediments are transported and deposited by flowing river water, providing an environment in which fluid mud layers can be formed. Acoustic method is mostly used to detect or monitor the fluid mud layer. However, since sound propagating in this layer suffers severe attenuation, it is important to estimate the accurate attenuation coefficient for various concentrations of fluid mud layer for the successful use of the acoustic method. In this paper, measurement results of attenuation coefficient for 3.5, 5, and 7.5 MHz ultrasounds were presented. The measurements were made in a small-size water tank in which suspended sediment samples with various sediment concentrations were formed using kaolinite powder. The results were compared to the model predictions obtained by attenuation coefficient model in which the mean grain size (called as Mass-median-diameter, D50) was used as input parameter. There were reasonable agreements between measured attenuation coefficients and model outputs predicted using the particle range of D50 ${\pm}20%$. The comparison results imply that although the suspended sediments consist of various-sized particles, sound attenuation might be greatly influenced by amount of particle with a size which has a larger attenuation than that of any particle in the suspended sediments for the frequency used.

Size Distributions of Trace Elements in Airborn Particulates Collected using Drum impactor at Gosan, Jeju Island : Measurements in Springtime 2002 (DRUM impactor를 이용한 대기 입자상 물질 중 원소성분의 입경분포 특성 : 제주도 고산지역의 2002년 봄철 (3.29-5.30) 측정 연구)

  • 한진석;문광주;류성윤;안준영;공부주;홍유덕;김영준
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.20 no.4
    • /
    • pp.555-569
    • /
    • 2004
  • Size -segregated measurements of aerosol composition using 8-stage DRUM impactor are used to determine the transport of natural and anthropogenic aerosols at Gosan site from 29 March to 30 May in 2002. Separation of ambient aerosols by DRUM impactor offers many Advantages over other standard filtration techniques. Some of the most important advantages are the ability to segregate into details by particle tire, to better preserve chemical integrity since the air stream doesn't pars through the deposit, to collect samples as a function of time, and to have a wide variety of impaction surfaces available to match analytical needs. Although the transport of Yellow sand is a well-known phenomenon in springtime, the result of measurement shows that not only soil dust but also anthropogenic aerosols, including sulfur, enriched trace metals such as Pb, Ni, Zn. Cu, Cr, As, Se, Br, are transported to Gosan in springtime. This study combines the size- and time-resolved aerosol composition measurements with isentropic, backward air-mass trajectories in order to identify some potential source regions of anthropogenic aerosols. As a result, during the NYS period, the average concentration of PM$_{10}$ was 46$\mu\textrm{g}$/㎥, Si, Al. S, Fe, Cl, K, Ca were higher than 1,000 ng/㎥ and Ti was about 100 ng/㎥. The concentrations of Zn, Mn, Cu. Pb, Br, Rb, V, Cr, Ni. At, Se ranged between 1 and 70 ng/㎥. More than 50% typical soil elements, tuck as Al, Si, Fe, Cd. Ti, Cr, Cu, Br. were distributed in a coarse particle range(5.0-12${\mu}{\textrm}{m}$). In other hand, anthropogenic pollutants, luck as S, N, Vi, were mainly distributed in a fine particle range (0.09-0.56${\mu}{\textrm}{m}$). During the YS period, PM$_{10}$ increased about 8 times than NYS period, and main soil elements, such as Al, Si, S, K, V, Mn, Fe also doubled in coarse particle range (1.15-12${\mu}{\textrm}{m}$). But Zn, As, Pb, Cu and Se, which distributed in the time aerosols (0.09-0.56${\mu}{\textrm}{m}$), were on the same level with or decreased than NYS period. Finally. except the YS Period, coarse particles (2.5-12${\mu}{\textrm}{m}$) are inferred to be influenced by soil, coal combustion, waste incineration, ferrous and nonferrous sources through similar pathways with Yellow Sand. But fine particles have different sources, such as coal combustion, gasoline vehicle, biomass burning, oil or coal combustion, nonferrous and ferrous metal sources, which are transported from China, Korea peninsula and local sources.ces.

The Effect of Ionic Group and MMA Contents on the Physical Properties of PU/PMMA Hybrids (PU/PMMA Hybrids의 물성에 대한 이온성기와 MMA함량의 영향)

  • Jeong, Chang Nam;Cho, Hang Kyu;Noh, Si Tae
    • Applied Chemistry for Engineering
    • /
    • v.8 no.4
    • /
    • pp.575-581
    • /
    • 1997
  • UDs were synthesized from two different polyols(PTMG, PBEAG), ionic chain extender(DMPA), EDA with $H_{12}-MDI$. PU/PMMA hybrids were prepared with free radical polymerization of MMA monomer in MMA-swelled PUD. PUD particle size and film properties were investigated ionic content and polyol type. Mechanical and thermal properties of PU/PMMA hybrid film were studied in terms of PU's ionic content and the venation of PU/PMMA compositions. As DMPA content increased from 2wt% to 10wt% in PUD, particle size of PUD decreased. PUD's particle size with ester type polyol was found to be smaller then ether type polyol used. Phase separation between hard segment(HS) and soft segment(SS) with ionic contents in PU was shown by the thermal, mechanical property measurement. Although the composition of MMA was changed from 0 to 40 wt% in PU/PMMA hybrid, the particle size of the hybrid did not increase. Using the ester type polyol, tensile strength of hybrid was found to increase by 2wt% - 6wt% DPMA content, but as higher content the strength of hybrid decreased. Moreover with the ether type polyol, tensile strength of hybrid was observed to increase by 2wt% - 4wt% DMPA content, while decreasing at higher content. PU and PMMA polymer molecule being mixed in molecular level was confirmed from the pattern of $T_g$ in DSC thermogram.

  • PDF

A Study on the Effect of Automotive Engine Performance by Using Carbon Nano Colloid Cooling Water (탄소나노콜로이드 냉각수를 사용하여 자동차 엔진성능의 향상에 관한 연구)

  • Yi, Chung-Seob;Lee, Byung-Ho
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.19 no.5
    • /
    • pp.134-142
    • /
    • 2011
  • Although combustion is essential in most energy generation processes, it is one of the major causes of air pollution. Exhaust pipes with circular fin were designed to study the effect of cooling the recirculated exhaust gases (EGR) of Diesel engines on the chemical composition of the exhaust gases and the reduction in the percentages of pollutant emissions. The gases examined in this study were oxides of nitrogen (NOx), carbon dioxide ($CO_2$) and carbon monoxide (CO). In addition, $O_2$ concentration in the exhaust was measured. The designs adopted in this study were about exhaust pipes with solid and hollow fins around them direct surface force measurement in water using a nano size colloidal probe technique. The direct force measurement between colloidal surfaces has been an essential topic in both theories and applications of surface chemistry. As particle size is decreased from micron size down to true Carbon nano Colloid size (<10 nm), surface forces are increasingly important. Nano particles at close proximity or high solids loading are expected to show a different behavior than what can be estimated from continuum and mean field theories. The current tools for directly measuring interaction forces such as a surface force apparatus or atomic force microscopy (AFM) are limited to particles much larger than nano size. This paper use Water and CNC fluid at normal cooling system of EGR. Experimental result showed all good agreement at Re=$2.54{\times}10^4$ by free convection and Re=$3.36{\times}10^4$ by forced air furnace.

Synthesis of Carbon Nanotubes Supported PtCo Electrocatalysts and Its Characterization for the Cathode Electrode of PEMFC (탄소나노튜브에 담지된 PtCo 촉매 제조 및 PEMFC Cathode 전극 특성)

  • Jung, Dong-Won;Park, Soon;Kang, Jung-Tak;Kim, Jun-Bom
    • Korean Journal of Materials Research
    • /
    • v.19 no.5
    • /
    • pp.233-239
    • /
    • 2009
  • The electrocatalytic behavior of the PtCo catalyst supported on the multi-walled carbon nanotubes (MWNTs) has been evaluated and compared with commercial Pt/C catalyst in a polymer electrolyte membrane fuel cell(PEMFC). A PtCo/MWNTs electrocatalyst with a Pt:Co atomic ratio of 79:21 was synthesized and applied to a cathode of PEMFC. The structure and morphology of the synthesized PtCo/MWNTs electrocatalysts were characterized by X-ray diffraction and transmission electron microscopy. As a result of the X-ray studies, the crystal structure of a PtCo particle was determined to be a face-centered cubic(FCC) that was the same as the platinum structure. The particle size of PtCo in PtCo/MWNTs and Pt in Pt/C were 2.0 nm and 2.7 nm, respectively, which were calculated by Scherrer's formula from X-ray diffraction data. As a result we concluded that the specific surface activity of PtCo/MWNTs is superior to Pt/C's activity because of its smaller particle size. From the electrochemical impedance measurement, the membrane electrode assembly(MEA) fabricated with PtCo/MWNTs showed smaller anodic and cathodic activation losses than the MEA with Pt/C, although ohmic loss was the same as Pt/C. Finally, from the evaluation of cyclic voltammetry(CV), the unit cell using PtCo/MWNTs as the cathode electrocatalyst showed slightly higher fuel cell performance than the cell with a commercial Pt/C electrocatalyst.

Research on the Dispersion Stability and Scale up of Carbon Slurry Fuel (카본슬러리 연료의 분산안정성 개선 및 scale up 제조연구)

  • Jo, Min-Ho;Yang, Mun-Kyu;Lee, Ik-Mo;Cho, Joon-Hyun;Kwon, Tae-Soo;Jeong, Byung-Hun;Han, Jeong-Sik
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2008.11a
    • /
    • pp.459-462
    • /
    • 2008
  • In manufacture of slurry fuel, the effects of process parameters on the carbon dispersion stability have been investigated. The particle size and contents of the carbon slurry taken from 3 (top, medium, bottom) positions in fuel reservoir were analyzed to estimate the dispersion of the carbon in Jet A-1. Through the application of various additives, it was found that NB463S84 additive showed the best dispersion and stability of carbon at accelerated gravity condition. The mixer performance was compared by the observation of height change of carbon-containing layer and measurement of particle sizes at the same conditions. Application of the mixing conditions obtained from the lab-scale to bench scale manufacture confirmed the practical feasibility of our research.

  • PDF

Preparation of Fine Titanium Nitride Powders from Titanium Trichloride (염화티타늄(III)으로부터 질화티타늄 미분체의 합성)

  • 이진호;장윤식;박홍채;오기동
    • Journal of the Korean Ceramic Society
    • /
    • v.27 no.7
    • /
    • pp.916-924
    • /
    • 1990
  • The preparatin of the fine TiN powders by reduction-nitridation of TiCl3-Al-N2 system was attempted in the temperature range from 350$^{\circ}$to 100$0^{\circ}C$. The formation mechanism and kinetics of TiN were examined, and the resultant TiN powder was characterized by means of XRD, PSA and SEM-EPMA methods. TiN was formed at temperatrue higher than $600^{\circ}C$. As an intermediate phase, AlTi was obtained. The apparent activation energy for the formation of TiN was approximately 4.2kcal/mole(600$^{\circ}$~90$0^{\circ}C$). The crystallite size and lattice constnat of TiN powder obtained in the temperature range from 600$^{\circ}$to 100$0^{\circ}C$ for 2h at the Al/TiCl3 molar ratio of 1.0 were 160~255A and 4.231~4.239A, respectively. According to PSA measurement, the mean particle size ranged from 14.0 to 14.8${\mu}{\textrm}{m}$.

  • PDF