• Journal of Aerospace System Engineering
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• v.15 no.3
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• pp.79-86
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• 2021

For a preliminary study on a thrust-throttleable Variable Flow Ducted Rocket, a gas generator and flow control valve were developed, and ground combustion tests were performed. The gas generator and flow control valve operated at the required performance level for parameters, such as heat-resistance, combustion-time, pressure, and temperature. The combustion characteristics of a fuel-rich solid propellant mixed with Boron/MgAl/AP, etc., were also analyzed. A Plunger-type flow control valve was designed to control the discharge flow area, and it was confirmed that the flow control valve was able to control the combustion gas flow rate and pressure. However, due to the reduction of the discharge flow area caused by adhesion of combustion products, the combustion pressure continuously increased. The analysis of the pressure increase is covered in Part 2 of this paper.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.605-612
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• 2016

A numerical analysis was performed on the effect of the design parameters of a bubble jet type microactuator on its liquid flow characteristics. The numerical models included the ink flow from the reservoir, bubble formation and growth, ejection through the nozzle, and dynamics of the refilling process. Because the bubble behavior is a very important parameter for the overall actuator performance, the bubble growth and collapse phenomena in an open pool were simulated in the present study. The drop ejection and refill process were numerically predicted for various geometries of the nozzle, chamber, and restrictor of the bubble jet microactuator. The numerical results from varying the design parameters can help with predicting the performance and optimizing the design of a microactuator.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.11
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• pp.806-812
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• 2012

Air curtains are widely used in commercial and public buildings to replace solid doors where traffic of people is predicted. At doorways where the solid door is open continuously or intermittently, an air curtain may be installed in order to reduce the flow of heat and moisture from the enclosed space to the outside. The purpose of this paper is to predict isolation performance of the single-sided air curtain when the wind is blowing. For the study, a numerical simulation is used to find the influence of various jet velocities on the efficiency of the single-sided air curtain device which is mounted at the side of the doorway. The isolation performance of the single-sided air curtain is evaluated by sealing efficiency which provides the assessment of the infiltration air ratio. According to the result of this study, the single-sided air curtain has lower sealing efficiency than downward-blowing air curtain. Therefore, for energy conservation in heating space, the single-sided air curtain is not recommended because of its low effectiveness.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.4
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• pp.129-134
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• 2024

In this paper, This paper is a liquid droplet discharge system using a water level sensor that can linearly detect changes in water level through experiments with an infrared sensor, a laser sensor, an ultrasonic sensor, and a capacitance sensor. SMPS, regulator 5V, and LDO 3.3V were designed for power supply. A water level sensor input ADC circuit and microprocessor were used. Solenoid valve control, pump output control unit for positive/negative pressure generation, CAN, Ethernet, UART communication, and USB for industrial communication were used. The change in pressure was confirmed through the change in water level, the change in pressure was minimized, and a system for discharging liquid droplets was implemented.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.3
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• pp.39-43
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• 2009

In this paper, the flow characteristics of underfill material driven by capillary action between flip-chip and substrate were investigated. Also, the effects of viscosity level and dispensing point of underfill on flow characteristics were investigated. Flip chip package size was $5mm{\times}5mm{\times}0.65^tmm$, the diameter of solder bump was 100 ${\mu}m$, and the pitch was 150 ${\mu}m$. It was full grid area-array type with 1024 I/Os. The glass substrate was used and the gap between the chip and substrate was 50 ${\mu}m$. For the experimental study, three different underfills with different viscous properties($2000{\sim}3700$ cps), and two different types of dispensing methods(center dot and edge dot) were used. The flow characteristics and filling time of underfill were investigated by using CCD camera. The results show that the edge flow was faster than center flow due to the edge effect, which was caused by the resistance of solder bumps. In case of edge dot dispensing type, the filling time was faster due to the large edge effect, compared to center dot dispensing type. Also, it was found that the underfill flow was faster and the filling time decreased as the viscosity level of underfill was decreased.

• Bulletin of Food Technology
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• v.4 no.2
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• pp.16-22
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• 1991

• 한국항공운항학회:학술대회논문집
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• 2006.05a
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• pp.85-89
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• 2006

• The Safety technology
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• no.109
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• pp.68-70
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• 2007

• Magazine of the Korean Society of Agricultural Engineers
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• v.2 no.2
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• pp.414-417
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• 1959

• The monthly packaging world
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• s.281
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• pp.60-63
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• 2016