• Title/Summary/Keyword: Spraying time

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Electrostatic Interference Model of EHD Spraying from an Array of Cone Jets in Electrospray Micro-Thruster

  • Quang Tran Si Bui;Byun Do-Young;Kim Man-Young;Dat Nguyen Vu
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.11a
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    • pp.30-33
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    • 2006
  • Onset voltage plays a crucial role in the design of a spray microthruster. This paper presents an analytical electrostatic model to predict the behavior of onset voltage in an array of emitters. The basic idea of this method is to superimpose the electric potentials obtained from each individual emitter in an array of emitters. The results show that if one emitter operates and the other neighboring emitters are dry, the potential required for cone-jet spraying generally increases as the emitter spacing decreases (due to electrical shielding). However at very close spacing the potential can decrease. If all emitters operate at the same time, the phenomenon that even at very close spacing the onset voltage required for cone-jet spraying increases merely as the emitter spacing decreases.

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Experimental study on the Formation and Growth of Silica Particles in $H_2/O_2$ Diffusion Flame by Electro-Spraying Method and Evaporation ($H_2/O_2$확산화염에서 전기수력학적 방법과 증발기에 의해 발생된 입자의 성장 비교에 관한 실험적 연구)

  • Sohn, S.H.;Yook, S.J.;Ah, K.H.;Choi, M.S.
    • Proceedings of the KSME Conference
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    • 2000.11b
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    • pp.168-173
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    • 2000
  • Flame aerosol synthesis technology refers to the formation of fine particles from gases in flame and is widely used in practical materials processing. In this paper, an experimental investigation was performed on growth of the silica particles that were generated in $H_2/O_2$ Diffusion Flame by the direct injection or TEOS using Electro-spraying method. in this flame aerosol synthesis, four main parameters or nos interaction (flame temperature, residence time or particle in flame, TEOS flow rate, applied voltage) for particle generation and growth was investigated along the axial direction above the burner. A fairly monodisperse non-aggregated particles were successfully obtained.

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A Study of Correlation between DCA and WHS in Fin-and-Tube Heat Exchanger (핀-관 열교환기에서 동적접촉각과 물맺힘량과의 상관관계에 관한 연구)

  • 황준현;고영환;신종민
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.10
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    • pp.786-791
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    • 2002
  • An experimental study on the behavior of the water hold-up by spraying of a fin-and-tube heat exchanger with regard to the surface characteristics, i.e., contact angles, was conducted. The dynamic contact angles (DCA) were measured, and water hold-up by spraying (WHS) was conducted in the experiment. It is found that heat exchanger surface characteristics, spray pressure, spray water temperature and heat exchanger surface temperature play an important role in WHS. In order to evaluate relationship between WHS and surface characteristics, test conditions are determined through a contour analysis. A correlation was proposed to predict WHS as a function of DCA. With its test efficiency and consuming time, the prediction method can be used to evaluate WHS performance.

Development of Fitting Process for Extra Long Stainless/Composite Material Pipes (초장축 스테인레스/복합재료 파이프의 피팅 공정 개발)

  • Park, S.H.;Lee, C.M.
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.2
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    • pp.77-82
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    • 2008
  • Rubbing-roller is used for manufacturing liquid crystal display, and static displacement of the rubbing-roller becomes bigger as length of the rubbing roller made of aluminum is getting longer. Therefore, material of the rubbing-roller is changed from aluminum to CFRP(Carbon Fiber Reinforced plastic). Recently thermal spraying is applied to manufacturing process of long rubbing-roller. The thermal spraying has disadvantages such as increment of manufacturing time and fraction defective caused by density of stainless steel particle. In this study, fitting process by drawing was suggested and FEM analysis with Tsai-Wu failure theory and fitting experiments are carried out to find adequate shrink allowance. The suggested shrink allowance gives proper adhesive force, and CFRP failure is not occurred. Furthermore, the fitting process is applied to long rubbing-roller and availability of the fitting process is studied by measurement of roundness, straightness and shear strength.

Improvement of Multiply Board Properties with Starch Spraying (전분 분무기술을 통한 다층지의 물성개선)

  • Lee, Hak-Lae;Ryu, Jeong-Yong
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.39 no.3
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    • pp.12-23
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    • 2007
  • Frequently spraying of natural starch slurry onto the formed wet web has been adopted to improve properties of paperboards. This conventional starch spraying technique, however, becomes less effective in strength improvement. In this study the effects of various factors including wet web dryness, quantity of starch slurry sprayed, and drying temperature on paperboard properties were investigated. Migration of starch granules into the webs appeared to cause a reduction in plybond strength when the web dryness was lower than this level. Wet webs should contain enough water to swell the starch granules, and at the same time they should be heated to a temperature high enough for complete cooking of the sprayed starches to occur. This suggested that preheating of the wet web can be employed to improve the plybond strength.

Operating Performance of Solenoid Valve and Nozzle Sets for Target Selectable Sprayers (이동형 국소 분무장치용 전자 밸브와 노즐 조합 작동특성)

  • Suh, S.R.;Kim, H.O.;Kim, Y.T.;Choi, Y.S.;Yoo, S.N.
    • Journal of Biosystems Engineering
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    • v.31 no.1 s.114
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    • pp.39-45
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    • 2006
  • Fundamental informations on performance of sets of solenoid valve and nozzle were necessary to develop a target selectable spraying system. The experiments were performed for the sets of solenoid valves and flat spraying nozzles at 3 levels of the operating pressures, and the obtained results are as follows; Rise time of the system pressure to reach up to 90% of the operating pressure after the valve turned was affected by nozzle size and operating pressure. Maximum overshoot of the system pressure was about 170% not affected by the sets of valve and nozzle and operating pressure. The system pressure after its settle down within 5% of the set pressure showed good uniformity in any condition of the experiment as less as 2.3% of its coefficient of variation. Time requirement to lower the system pressure down to 50% after the valve power turned off was affected by valve and nozzle set and operating pressure.

Effects of PP333 Spraying on Growth of Soybean (PP 333 처리가 대두 생육에 미치는 영향)

  • 정병관
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.32 no.2
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    • pp.181-187
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    • 1987
  • The objectives of the study were to reduce lodging during the stormy rain period of soybean growing season in Korea, and to find out the most efficient foliar spraying of pp 333 solution in order to increase tolerance to lodging of soybean plants. The concentration of the pp 333 solution were three, five and eight percent and the time of spraying were 35th day after seeding and at flowering time. The most efficient foliar spraying practice was to spray five percent solution of pp 333 on the 35th day after seeding, resulting in reduced stem length damage of soybeans alone with shortened plant height and stabilized yield of soybean grains.

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A Study on Drone Nozzle Design for Greenhouse Shading (온실차광을 위한 드론 전용노즐 설계에 관한 연구)

  • Ungjin Oh;Jin-Taek Lim
    • Journal of the Institute of Convergence Signal Processing
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    • v.24 no.4
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    • pp.249-254
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    • 2023
  • Recently, the distribution of drones is being activated by saving farmers' working time and protecting them from harmful human bodies from pesticides due to the mission of spraying pesticides using drones. It is possible to compensate for various shortcomings derived from the existing pesticide spraying method, wide-area control and helicopter control. Recently, the smart farm expansion policy has actively used it to generate profits for farmers by increasing harvests by monitoring growth information of various crops based on IoT in real time and collecting big data on key variables, and related drone industry technologies are also being developed. In this study, drones were applied to the work of shading greenhouses to secure diversity in agricultural application fields, and basic research on the greenhouse environment was conducted to materialize the technology related to shading. In order to provide high-quality light in consideration of the internal and external environment of the green house, basic research was conducted to enable light-shielding missions using drones through nozzle design for uniform spraying of nozzles of drones, light-transmitting rate analysis of green houses, and light-shielding agent application experiments.

Analysis of Machined Surface Morphology According to Changes of Surface Condition in Micro Particle Blasting (미세입자 분사가공 시 표면 조건 변화에 따른 가공 표면 형상 분석)

  • Choi, Sung-Yun;Hwang, Cheol-Ung;Kwon, Dae-Gyu
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.5
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    • pp.70-75
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    • 2018
  • This study analyzes the change of Al 6061-T6 specimen surface shape when undergoing microparticle spraying and analyzes the influence of factors on the experiment. Fine particle spraying is applied to the specimen and the surface shape of the processed surface is measured through a surface shape measuring device. The measured data was analyzed by the ANOVA method to investigate the effect of factors such as particle, nozzle diameter, pressure, injection height, and injection time on the injection depth and injection diameter.

Effect of preharvest aminoethoxyvinylglycine spraying time on fruit quality of 'Nagasawa Hakuho' peach (Prunus persica Batsch) during shelf-life (Aminoethoxyvinylglycine 처리시기가 복숭아 '장택백봉'의 유통 중 품질에 미치는 영향)

  • Wang, Mao-Hua;Lee, Ug-Yong;Oh, Kwang-Suk;Lee, Eun-Gu;Ahn, Young-Jik;Hwang, Yong-Soo;Chun, Jong-Pil
    • Korean Journal of Agricultural Science
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    • v.39 no.4
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    • pp.503-509
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    • 2012
  • This research aimed to investigate the effect of preharvest spray of aminoethoxyvinylglycine (AVG) on fruit quality of 'Nagasawa Hakuho' peach (Prunus persica Batsch). The efficacy of various concentrations of AVG (75 and 150 mg/L), which inhibits the ethylene biosynthesis, was evaluated under field conditions. Treatments were performed 21, 14 and 7 days before harvest, respectively. Fruit weight, flesh firmness, soluble solids content, acidity, ethylene production, respiration rate and skin color difference were determined at harvest time and during shelf-life at $25^{\circ}C$. Results indicated that the most appropriate timing of AVG spraying was 21 days before harvest at the concentration of 75 mg/L as shown higher firmness at harvest time and lower ethylene production and respiration rate during shelf-life. Spraying of AVG during near harvest period (14 to 7 days before harvest) inhibited fruit growth slightly, independent of concentration and did not affect fruit quality in 'Nagasawa Hakuho' peach.