• Journal of the Korean Society of Industry Convergence
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• v.22 no.5
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• pp.553-559
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• 2019

Various types of nozzles have been used to cope with fire in ships. However, in Korea, precise nozzles that perform fine spraying function are required for fire fighting in case of fire in a ship, and most of these nozzles depend on imports. Therefore, in this study, we developed various types of nozzles to develop the water spray nozzle for evolving fire in the engine room of the ship, and developed an optimal nozzle through flow analysis and fire test. For this purpose, we selected the materials that can satisfy the characteristics of existing nozzle materials and developed the design technology and processing technology in the nozzle considering fluid flow to achieve optimal water spraying performance. In order to develop an optimal nozzle, the flow through the finite element analysis was first analyzed and the nozzle was manufactured. As a result of flow analysis of the developed nozzle, the maximum velocity at the outlets of four holes at 0.3 MPa was about 3m/s and about 0.15 MPa. In addition, when the pressure at the inlet was 1.8 MPa, it showed the outlet speed of about 18m/s and a pressure of 1.2 MPa.

• Journal of the Korean Society of Safety
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• v.18 no.1
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• pp.28-32
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• 2003

The present study investigates the spray characteristics of water mist nozzle with mid-low pressure for fire suppression. The examined nozzle types are swirl and spiral nozzle. The result shows that K factor of water mist nozzle is much smaller than those of general sprinkler. Spray angle of spiral nozzle is largest and more than $150^{\circ}$. SMD(Sauter Mean Diameter) of water mist nozzles is ranged between 100 and 200$\mu\textrm{m}$through measuring by image processing method. The spray pattern of spiral nozzle represent that water flux of first stream is 2 times larger than that of second stream. This study will contribute better understandings of the water-mist spray characteristics and useful daia for developing the water-mist nozzles.

• International Journal of Computer Science & Network Security
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• v.22 no.12
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• pp.178-184
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• 2022

Renewable energy sources based on solar radiation, wind energy, geothermal energy, and biomass energy have now reached the level of industrial application. A new way to generate electricity using low-potential heat is to install a hydro-steam turbine. In hydro-steam turbines, hot water is supplied directly to turbine rotor nozzles without prior separation into steam and water in separators, which significantly increases the efficiency of hot water energy use. Such turbines are suggested to be used as autonomous energy sources in geothermal heating systems, heating water boilers and cooling systems of chemical reactors, metallurgical furnaces, etc. The authors conclude that the installation of hydro-steam turbines in heating plants and process boiler plants can also be effective if the used exhaust steam-water mixture at the turbine outlet is used to heat the network water or as return water.

• Journal of Biosystems Engineering
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• v.29 no.3
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• pp.225-232
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• 2004

A new type of garlic peeling chamber has been developed which separates and peels garlic cloves using high-Pressure water Jets. The cylindrically-shaped chamber was fabricated with stainless steel plate and has a number of drilled holes, which function as solid-stream spray nozzles, on its interior wall. The chamber was divided into upper and lower section so that water can be applied at different pressures from each section. Three chambers of similar design were tested to evaluate their performances according to various pressure levels. The strongest correlation was observed between the pressure difference(lower-upper) and the proportion of unseparated and completely-peeled garlic cloves. Hanji-type garlic required higher or pressure difference to separate cloves from garlic bulbs than nanji-type garlic. On the other hand, protective leaves(skin) from the cloves were peeled more easily in case of hanji-type garlic. As a result of three consecutive peeling operations, the proportion of completely-peeled garlic cloves changed in the order of 80.1, 82.6, 84.1% in case of hanji-type, and 19.6, 29.1, 40.2% in case of nanji-type garlic.

• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.1060-1068
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• 2019

This work aims to establish a model of a primary water stress corrosion crack growth rate of Alloy 690 material for the head penetration nozzles of Korean pressurized water reactors. The test material had an inhomogeneous microstructure with bands of fine-grains and intragranular carbides in the matrix of coarse-grains, which was similar to the archive materials of the head penetration nozzles. The crack growth rate was measured from the strain-hardened materials as a function of the stress intensity factor in simulated primary water at various temperatures and dissolved hydrogen contents. The effects of strain-hardening, temperature, and dissolved hydrogen on the crack growth rate were analyzed independently, and were then introduced as normalizing factors in the crack growth rate model. The crack growth rate model proposed in this work provides a key element of the tools needed to assess the progress of a stress corrosion crack when detected in thick-wall Alloy 690 components in Korean reactors.

• Journal of computational fluids engineering
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• v.11 no.4 s.35
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• pp.56-61
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• 2006

Numerical simulation has been performed to investigate the characteristics of the mist flow through the fire suppression nozzles. The commercial CFD software, FLUENT with the proper modeling was applied for analyzing both the internal and external flow of the spray nozzles. Computations were made for the full cone nozzle in the operation range of the low pressure and high flow-rate. To validate the present computational procedure, numerical results are compared with measurements in terms of K-factor, SMD, axial spray velocity and spray angles. Numerical results suggested that the present numerical model can be used as an adequate tool for a design purpose of mist-spray nozzles.

• Journal of Bio-Environment Control
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• v.8 no.4
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• pp.223-231
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• 1999

The one of basic functional conditions of suspended overhead sprayer, which is openly made use of irrigating on bedding plants in greenhouse, is to be kept the growing uniformity of bedding plants by making uniformly the spraying irrigation depending on the distribution of sprayed water. This study was performed to find out the optimum position of sector formed injection nozzle which is placed from the top of plant 0 the tip of the nozzle to keep spraying uniformity. The test of spraying distribution using a overhead sprayer, which was installed in a row of sector formed injection nozzles, was performed The measuring factor to represent spraying distribution was the water weight filled in each cup when the overhead sprayer was moving across the upside of the cups which were placed directly under the nozzles on keeping the distance from nozzle tip. The test results were as following , The standard mr of weights of each cup filled with spraying water was lower values at Position far from more than 60cm under nozzle tip. The driving speed variation of sprayer was not effected on spraying uniformity but the spraying water weight was inversely proportioned to the speed. To make best spraying uniformity, it was represented that the tip of the nozzle is positioned to keep the distance which the top of plants is placed at the second cross point of each injection sector of nozzles.

• Korean Journal of Metals and Materials
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• v.48 no.5
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• pp.424-429
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• 2010

In the RH process, it is possible to obtain quicker processing times by enhancing the decarburization rates at a low carbon range of steel melt through Ar gas injection into the vacuum vessel. The RH decarburization reaction was simulated through a dissolved oxygen removal reaction by injecting nitrogen into a 1/8 scale RH water model system. The gas nozzles for the N$_{2}$ injection into the vacuum vessel were located at the lowest level of the vessel's outer wall. The nitrogen bubbling in the vacuum vessel resulted in an increase in the reaction rate constant, which rose in accordance with an increase in the bubbling flow rate and number of nozzles used. However, there was almost no variation in the reaction rate constant, which depended on the horizontal positions of the bubbling nozzles.

• Journal of Biosystems Engineering
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• v.41 no.3
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• pp.201-207
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• 2016

Purpose: A water-spraying type automatic glochids removal system for cactus (Opuntia humifusa) stem was developed, and its performance was evaluated. The system was developed to reduce intensive human labor in removing glochids from cactus stem skin without inducing damage prior to further processing into value-added products. Methods: The developed system consists of conveyor and water-spraying systems. The conveyor system delivers cactus stems through water-spraying compartments and finally to a collecting box. In order to remove the glochids, rotating nozzles spray water over all areas (i.e., front and back faces and sides) of the cactus skin under controlled water pressure. Operating conditions such as conveyor speed, water pressure, angle of water-spraying nozzles, distance between conveyor belt and rotating nozzles, and angle of cactus flipping slide were adopted from our previous study and applied on the system design and manufacturing. The performance of glochids removal was evaluated by counting the number of glochids on the cactus stem before and after processing on the system. Results: The developed system performed efficiently and effectively under the pre-studied operating conditions except for the angle of cactus flipping slide. The new system had a glochids removal ratio of 94.1% without damaging the cactus skin. Considering the original number (approximately 30-60) of glochids, the remaining number was low (1-4), and most of them were found at the side edge of the cactus stem. This system can remove glochids from 360 cactus stems in 1 hr regardless of cactus size. Conclusions: The performance of the new system in glochids removal without damaging cactus skin is superior to any other existing device (i.e., brush type, rubber-friction type, and agitation type). The system is expected to be applied in cactus (O. humifusa) processing facilities.

• Journal of ILASS-Korea
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• v.9 no.3
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• pp.15-21
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• 2004

The removal of the dusts in the subway stations, tunnels, factories and buildings becomes issue for comfortable indoor and outdoor conditions. There has been used an automatic self-cleaning filter system to collect the dusts. In general, the collected particles are removed by water spray nozzles. The new design for improving the cleaning efficiency of collected dusts and reducing the supplied water is the concept of the plane array of demister filters and the twin-fluid nozzle for mixing compressed air and water in the automatic self-cleaning filter system. Results show that the cleaning efficiency of twin-nozzle filter systems is 99.1%, compared to 47% in the conventional filter system. Therefore the automatic self-cleaning filter system using twin-fluid nozzle filter systems reduces water supplied in the filter system, and increases cleaning efficiency and drying efficiency.