• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.388-403
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• 2018

We investigated design requirements of vent lines for Sodium-Water Reaction Pressure Relief System of Prototype Generation-IV Sodium-Cooled Fast Reactor. We developed design requirements of areas of the rupture disks of the steam generator, a diameter of the gas vent line of the sodium dump tank, a diameter of the gas vent line of the water dump tank, a diameter of the water dump line of the steam generator. With the design requirements, we calculated the time to vent fluid inside the steam generator and analyzed the transient pressure behavior, also evaluated the close pressure value of the isolation valve of the water dump line. Our results are expected to be used as basis information to design Sodium-Water Reaction Pressure Relief System of Prototype Generation IV Sodium-Cooled Fast Reactor.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.2 s.179
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• pp.122-128
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• 2006

This study focuses on a performance improvement of the vent silencer using acoustic analysis. Since the vent silencer is generally used for a high level shock noise, it should be designed to reduce a wide frequency band noise. In the designing stage of the vent silencer, structural shapes of diffuser and splitter are the most significant design parameters. Effects of modifying the original structure of the diffuser and the splitter are analyzed and evaluated. From the results, It is found that the diffuser with two pipes and double-step structure more effectively reduces a wide frequency band noise but the increment of the number of splitters is not desirable.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.170-179
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• 2017

We investigated design requirements of feed water drain and hydrogen vent systems for the sodium-water reaction pressure relief system (SWRPRS) of the prototype generation IV sodium cooled fast reactor (PGSFR). We evaluated the areas of the gas vent pipe of the water dump tank and the length of the water drain pipe of the steam generator to rapid drain of the water steam inside the steam generator for the normal and refueling operations, respectively. We also calculated the diameter of the gas vent pipe of the sodium dump tank which met its design pressure.

• Fire Science and Engineering
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• v.22 no.4
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• pp.1-10
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• 2008

In this study, the effects of vent location, outside temperature, wind velocity and fire size on the performance of natural venting of the vertical vent designed according to NFPA 204 standard and fire characteristics were numerically investigated using CFAST. In cases of the Vent located on most upper wall, lower outside temperature and lower wind velocity, vents met the performance criteria of venting. The larger fire size becomes, the more mass flow rate through a vent becomes, but the lower interface height of smoke layer becomes, so that vent didn't meet the performance criteria of venting. It should be noted that a natural vertical vent be designed considering maximum outside temperature and maximum wind velocity and developing a design fire accurately in order to meet the performance criteria of venting.

• Current Industrial and Technological Trends in Aerospace
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• v.9 no.1
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• pp.130-138
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• 2011

A vent relief valve performs as a safety valve, which ensures ventilation of propellant tank during filling and protection from tank overpressure after filling. Because of the reliability and cost saving, the virtually same vent relief valve has been used on all US cryogenic liquid fueled launch vehicles. Some modification to the valve has been applied to satisfy the various mission requirements of launch vehicles. This paper reviews the main technology trends of the vent relief valve applied to the propellant feed system for launch vehicle with respect to design and manufacture. This paper also introduces the operating technology of vent relief valve applied for launch vehicles of advanced countries in space development.

• Fire Science and Engineering
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• v.33 no.4
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• pp.41-49
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• 2019

In the present experimental study, based on a real-scale theater, a 1/14 reduced-scale model was constructed, and the effects of natural vent and fire curtain in fire of a theater stage were investigated. The case without fire curtain under the opened natural vent showed lower temperatures in the stage, whereas the case with fire curtain under the opened natural vent showed lower temperatures in the auditorium. On the other hand, through analyzing the starting time of the temperature rise at the point near the proscenium opening in the auditorium, it was found that the opened natural vent condition can delay the starting time of smoke spread from the stage to the auditorium and suppress the temperature rise in the auditorium. Under the present experimental conditions, the fire curtain installation did not affect significantly the velocity and mass flow rate of the outflow through the natural vent of the stage, which might be due to openings in the stage. The present results can be used to examine the effects of natural vent and fire curtain in a real-scale fire of a theater and to check the accuracy of the numerical simulation code.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.741-747
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• 2010

Vent-relief valve performed as a safety-valve combination for liquid propellant feeding system of space launch vehicle, which can vent the vaporized oxygen vapor during both filling cryogenic oxidizer into tank and flight. We have designed vent-relief model by using the AMESim code to predict dynamic characteristics and simulate pneumatic behavior of valve. To validate valve model we have compared by opening time in vent model, and opening/closing pressure by mathematical methods and improved the accuracy through numerical flow analysis by using FLUENT code. In this study, we had verified design parameters and analyzed operating performances. We can use these analysis results to precedent development study on propellant feeding system of Korea Space Launch Vehicle.

• Korean Journal of Computational Design and Engineering
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• v.14 no.5
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• pp.330-337
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• 2009

Nowadays a lot of high-tech electronic products such as TVs, monitors and camcorders are being developed. The more functions the electronic devices have, the more heat problems occur. Therefore, most of electronic products have air-ventilation holes to eliminate heat that is generated inside the products. The shapes of ventilation holes are usually complicated since aesthetic appearance of the products is important these days. In order to create those complicated shapes, designers should do time-consuming jobs because most of commercial CAD systems do not provide the functions that create patterns of lofted parts along freeform surfaces. In this research, an automated air-ventilation hole modeling system was proposed. The system generates patterns of lofted objects on freeform surfaces. Standard process to create air-ventilation holes manually was established, and vent-hole types and pattern types were classified into several categories. Designers can create many kinds of vent-holes by combining vent-hole types and pattern types. Users can also utilize user-defined pattern which can give users more flexibility. Developed system was applied to several design examples and the results are presented.

• Journal of Sensor Science and Technology
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• v.15 no.1
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• pp.20-27
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• 2006

This paper presents a gas measurement system for deciding hole positions on a PU middle-sole mold from computed gas amount. The optimal number of holes and their positions on the shoe mold are decided from statistical experiment results to overcome the problem of excessive expenses in gas vent exchange. This paper also describes a gas vent exchange mechanism using computer vision system. The gas hole detecting process is based on computer vision algorithms represented as a simple Pattern Matching. The experimental result showed us that the system was useful to calculate the number of holes and their positions on the shoes mold.

• Journal of Navigation and Port Research
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• v.48 no.4
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• pp.274-283
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• 2024

Climate change is currently one of the most pressing environmental issues, primarily caused by carbon emissions from fossil fuel usage. As a result, alternative fuels that effectively reduce carbon emissions are garnering more attention. Among these alternatives, hydrogen has numerous advantages, such as its ability for large-scale storage and transport. However, it is crucial to prioritize safety measures, particularly in facilities that handle hydrogen, due to its highly flammable and fast-spreading nature. This study aims to compare and analyze the placement of supply and exhaust vents to efficiently release hydrogen in the event of a leak in an enclosed space. The experiments involved six different scenarios, each with various combinations of supply and exhaust vents. To ensure the experimental process's safety, helium, which shares similar physical properties with hydrogen, was used to analyze the internal oxygen concentration during ventilation system operations. The results revealed that among the six scenarios, Case 2, which employed a lower side supply vent and an upper side exhaust vent, exhibited the shortest ventilation time of 4 minutes and 30 seconds. Additionally, the decrease rate in oxygen concentration was examined in the upper, middle, and lower areas. Ventilation utilizing an upper surface supply vent and two exhaust vents on the upper surface and upper side (Case 6), showed lower oxygen concentration values in the upper area, while Case 2 yielded lower values in the middle and lower areas. Therefore, it is crucial to select an appropriate supply and exhaust vent configuration considering the space's characteristics and usage environment.