http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
도덕희,천강우,Nao Ninomiya,최병철 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.7
Analyses on the gas dispersion from a vent mast have been conducted using fire dynamics simulator (FDS) for a 50000 dead weight tonnage (DWT) gas-fueled bulk carrier, under the assumption that methane and propane gases are discharged through a pressure relief valve in the vent system of the fuel storage tank. To assess the transient flammable extents for representative vent scenarios, the initial conditions of venting gases were selected as propane at –30 °C and methane at –150 °C, when wind velocity was set to 2 m/s in the ship exterior. The same ship layout was applied in each of these scenarios with different configurations of the inner components of the vent mast outlet. As a result, the cases with a plate head in the current vent mast outlet did not satisfy international code requirements for the safety distance of the vent mast location in ships powered by low-flashpoint fuels. However, the flammable extents of the venting gases could be significantly reduced by a novel vent system in which a swirl head and nitrogen diluent at 20 °C were adopted. Therefore, a safety design procedure considering gas dispersion characteristics was required to determine the location of the vent mast outlet in the gas-fueled vessel to satisfy the minimum requirements of the international code.
Instability of wall jet produced by twodimensional inclined jet
Gentaro Takeda,Yu Ito,Kenji Yamashiro,Hideyuki Takahashi,Nao Ninomiya,Yuya Uranaka,Jurai Fujikura 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1
This paper focuses on a two-dimensional jet that impinges on a sloping wall surface. It investigates the vibration behavior and wall jet development morphology during wall impingement. Flow visualization experiments of jets impinging on a plate arranged vertically and at an angle of 65° were conducted. In the range where the distance between the jet nozzle and the plate is from the near field to the transition region, the vibration form of the impinging jet changes sensitively. The range of the distance between the jet nozzle and the impinged plate where no shear vortex forms on the wall surface is expanded by the inclined impinging jet. On the upward side, where the fluid easily flows due to the inclined impinging jet, an increase in the vibration frequency was also confirmed as the wall jet velocity increased. PIV measurements showed that wall jet separation after inclined impinging was delayed in comparison with vertical impinging, and a stable wall jet was formed.
Gentaro Takeda,Yu Ito,Kenji Yamashiro,Hideyuki Takahashi,Nao Ninomiya,Jurai Fujikura,Shun Akutsu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.11
This paper focuses on the development formation of two-dimensional impinging jets. Since it is known that vibration of a two-dimensional jet injected from a gas wiping nozzle affects the morphology of the coating surface, control of the jet properties is a very important issue. In this paper, jets with different initial velocity distributions were created, depending on the internal shape of the nozzle, and the behavior of the impinging two-dimensional jet in the transition region was evaluated by flow visualization. One nozzle (contoured nozzle) had a curvilinearly contracting shape as the flow approached the nozzle injection port, and the other (straight nozzle) was provided with a parallel part having a length 17 times the width of the nozzle gap in the flow path of the nozzle injection port. The jets ejected from these nozzles differed significantly in the velocity profile and in the vortex formation at the edges of the jet before impingement. There were also differences in the wall jet thickness and jet velocity attenuation of the wall jet. The difference in the wall jet characteristics due to the nozzle type is remarkable in impingement at the beginning of the transition region, but the difference decreases with the impinged wall distance where collapse of the large-scale vortex is seen even in the transition region.
ACTOR'S VS. OBSERVER'S PERSPECTIVES IN VLOGS
Akinori Ono,Aoi Matsuzaki,Junya Kunitake,Katsumi Arita,Mao Sinya,Nao Nitta,Nobutaka Ninomiya,Risa Tsuboi,Tomoaki Nakamura 글로벌지식마케팅경영학회 2023 Global Marketing Conference Vol.2023 No.07
Previous research has compared still images employing the actor’s perspective to those employing the observer’s perspective and found that the former increases service evaluations if the consumers are promotion-focused, whereas the latter increases service evaluations if the consumers are prevention-focused. The research compares three kinds of vlogs, i.e., vlogs employing the actor’s perspective, vlogs employing the observer’s perspective without the actor’s face, and vlogs employing the observer’s perspective with the actor’s face. The results show that the highest service evaluations are induced by the actor’s perspective in case of promotion-focused consumers, whereas they are induced by the observer’s perspective without the actor’s face in case of prevention-focused consumers.