• Journal of Institute of Control, Robotics and Systems
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• v.17 no.5
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• pp.444-450
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• 2011

Environmental change, labor shortage, and international trade politics make agricultural automation ever more important. The automation demands the highest technology due to the nature of agriculture. In this paper, autonomous pesticide spray robot system has been developed for rose farming in the glass house. We developed drive platform, navigation/localization system, atomization spray system, autonomous, remote, and manual operation system, and monitoring system. The robot will be a great contribution to automation of hazardous labor-demanding chore of pesticide control in glass houses.

• Journal of Biosystems Engineering
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• v.10 no.1
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• pp.13-23
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• 1985

Spraying method from the paddy-field levee is known to give insufficient penetration of the spray droplets to the rice stem of the densely grown plants, which is generally encountered at the last stage of rice growth. This study was intended to investigate the spraying system to solve this existing problem. As an approach, it was attempted to develop the boom-with-nozzle, between-the-row application system. Several types of nozzles and their different arrangements in the boom were tested in the field to measure the penetration-reaching distance and the uniformity of spray droplet distribution. The results of the study are summarized as follows: 1. Field experiments by the spraying method from the paddy-field levee showed to have practically no penetration of the spray droplets to the portion of the plant stem with the normal flow volume generally applied and thus need for improving present spraying method. 2. It was found that, considering both the uniformity of the spray droplet distribution and performance rate, the most efficient type of nozzle in the between-the-row boom-type spraying system was one that has core-insert hollow-cone with some clearance between the cone and tip. 3. When tested by applying the spraying method of between-the-row, the nozzle pressure did not affect the uniformity of spray droplet distribution. However, the nozzle pressure had a positive effect on the penetrating-reaching distance of the facing side of the rice stem and did not affect much on that of the opposite face of the stem. It was also found that the maximum pressure to affect the penetration-reaching distance was about $10kg/cm^2$. 4. The uniformity of the spray droplet distribution in the between-the-row system was greatly affected by the height and orientation of the nozzles in the boom. Based on experimental work for the different type of the boom-with-nozzle arrangements, it is recommended that the position of nozzle is set at about 0.45 m above the ground and two nozzles in the boom are oriented to be faced with each other with some angle such that the droplet stream from the nozzle would not directly face with each other.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.2
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• pp.55-63
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• 2013

For a large-scale semiconductor manufacturing clean room, the energy consumed in an outdoor air conditioning system to heat, humidify, cool and dehumidify incoming outdoor air is very large. In particular, the energy requirement to humidify outdoor air in the winter season is generally known to be high. Recently, in order to overcome the high energy consumption nature of a steam generator in a conventional steam humidification type outdoor air conditioning system, an air washer is often introduced instead of the steam generator in the outdoor air conditioning system, which can be called a water spray humidification type outdoor air conditioning system. Therefore, the assessment and comparison of the annual energy consumed in the steam humidification type and the water spray humidification type outdoor air conditioning systems deserves to be examined in order to reduce the outdoor air conditioning load of a clean room. In the present study, a numerical analysis was conducted to obtain the annual electric power consumption of the two outdoor air conditioning systems. It was shown from the comparison of the numerical results that the water spray humidification type outdoor air conditioning system can reduce about 30% of annual electric power consumption of the steam humidification type outdoor air conditioning system.

• Asian Journal of Atmospheric Environment
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• v.8 no.2
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• pp.89-95
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• 2014

There have been a lot of efforts to keep permissible emission standards and to reduce the amount of emitted air pollutants. There are several air pollution control equipments, however, wet scrubber is used to remove particulate matters and gaseous pollutants simultaneously, even if it has low collection efficiency in the particle size less than $5.0{\mu}m$. To overcome this problem, we introduced a spray tower scrubber with an electrospray system which a high voltage was indirectly applied. We found that collection efficiency of fine particles in the electrospray system was improved by increasing electrical field strength and the ratio of liquid-gas flow rate (from 41% to 84% for $0.3{\mu}m$ particles). In addition, a number of small droplets generated from an electrospray system led high collection efficiency, resulting from electrostatic attraction between droplets and particles and higher collision frequency. Therefore, we can conclude that the introduction of an electrospray system is quite effective to increase the particle removal efficiency of a spray tower scrubber.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.75-80
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• 2001

The present article deals with the numerical calculations for the inter-spray impingement of two diesel sprays under the conditions of high injection pressure. The Wave model involving the cavitation effect inside the nozzle was used for describing the atomization process. In particular, a hybrid model for drop collision was newly suggested in this study and compared with the O'Rourk's model, which has been widely used for diesel sprays. The impingement angles of 60 and 90 degrees were considered for simulation of non-evaporative diesel sprays. The calculated results for tip penetration were compared with experimental data and the Sauter Mean Diameter(SMD) characteristic was analyzed. It was concluded that the hybrid model slightly shows better agreement with experimental data than the O'Rourke's model. However, the more elaborate study should be needed for better understanding of spray-to-spray impingement phenomena.

• Journal of ILASS-Korea
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• v.13 no.3
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• pp.149-155
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• 2008

An experimental study was performed to understand spray characteristics of the rotary atomizer for the slinger combustor. In this fuel injection system, fuel is injected and atomized in the combustor by centrifugal forces to engine shaft. The experimental apparatus consists of a high speed rotational spindle, rotary atomizer, pressure tank and acrylic case. The droplet size and velocity were measured by PDPA (phase Doppler particle analyzer), and spray was visualized by using high speed camera and Nd:Yag laser-based flash photography. From the test results, the droplet size (SMD) is largely affected by rotational speed, mass flow rate and the number of orifice. As the experimental results, we could understand the spray characteristics of the rotary atomizer for the slinger combustor and obtain the optimum shape of the rotary atomizer which is suitable for the small gas turbine engine.

• Journal of ILASS-Korea
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• v.4 no.2
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• pp.40-46
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• 1999

Experimental investigation of unsteady impinging diesel spray on the flat plate have been carried out using high speed camera and Malvern system. The density ratios of ambient gas to diesel fuel were varied using $N_2$ and Ar gas in the case of 14.9, 21.2, 28.4, 35.1, 40.4, and 50.1. With the increase of gas density ratio, the radial penetration is decreased due to the resistance of the ambient gas. With the increase of the gas density ratio and the distance between nozzle tip and flat plate, the height of spray is increased due to the entrance and circulation. With the increase of gas density ratio, SMD is decreased on the nearby position at the center of flat plate, but SMD is increased on the far position. As the distance between nozzle tip and flat plate is increased, SMD is always decreased.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.1
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• pp.118-130
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• 1995

Fuel spray in a gasoline engine is a significant factor for the decision of engine power, pollutant emission and the design of intake manifold system. Three kinds of fuel which has other physical properties are chosen in this study, and it is observed using an image processing method that the mechanism and structure of free fuel spray with a throttle type gasoline injector, and the detailed characteristics of droplet size and velocity distributions are obtained by macro and micro-scopic measuring method respectively. It is verified that the initial breakup behaviors are depended on We like the result of Reitz's study, and also observed that the spray of octane and solvent with Re of 210~330 and 270~330 respectively are better than ethanol which has relatively high density and viscosity.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.5
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• pp.97-104
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• 2007

The object of this work is to analyze the macroscopic spray performance and atomization characteristics between diesel and biodiesel fuels. In this study, the effects of mixture ratios of biodiesel fuel on the spray tip penetration, fuel injection rate, spray cone angle, and the atomization characteristics such as droplet size, droplets distribution, and spray arrival time according to the axial distance were investigated at various injection parameters. It is revealed that the injection rate is more affected by injection pressure than mixture ratio. And, the spray development process is closely matched between diesel and biodiesel fuels. However, the droplet atomization characteristics of biodiesel shows deteriorated results as the mixture ratio of biodiesel increased because of the high viscosity and density.

• Journal of ILASS-Korea
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• v.6 no.1
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• pp.9-17
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• 2001

The effect of air entrainment in twin-fluid spray structure is investigated experimentally by varing the amount of itemizing air. The air entrainment is expected to affect on droplet size and velocity, droplet number density, turbulent kinetic energy and vorticity. PDA(Phase Doppler Anemometer) and PIV(Particle Image Velocimetry) system are used to measure those important factors in analyzing spray structure. The results show that spray structure consists of three distinctive regions ; the atomizing region near nozzle, characterizing strong convective effect, the central core region where droplets are accelerated, and the spray sheath region where droplets are decelerated due to air entrainment. The local air entrainment rate is largest near nozzle, characterizing strong turbulent kinetic energy and vorticity but deceases along axial distance.