• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.64-73
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• 1995

A numerical simulation of heat and fluid flow for predicting the effect of passage arrangement in automotive heat battery has been performed. The system is assumed to be a two-dimensional laminar flow and isothermal boundary is applied to the surface of the latent heat storage vessel. In the case of ideal heat battery the flow rate into each flow passage is evenly distributed. The various models are considered in the view of pressure drop and bulk temperature. The effects on the efficiency of the heat battery are examined by varying geometrical factors such as flow passage clearance, length of a inlet and outlet tank and the length of a latent heat storage vessel. The flow clearance is a very important -factor on the efficiency of a heat battery. As the flow passage clearance becomes narrow, the flow distribution becomes uniform and the bulk temperature increases, however the pressure drop is large. Therefore, optimal flow passage clearance has to be chosen. The present work can be used in optimizing heat battery efficiency.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1841-1850
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• 2013

The various types of fishways are installed at the multi-functional weirs in the four major rivers to minimize the negative effect due to the construction of the transverse structures. The movable weir was installed at the upstream of the ice-harbor type artificial fishway of the Dalseong weir in the Nakdong river, which can control the fishway flowrate regardless of the river flowrate. The incoming flowrate to the artificial fishway is closely related with the hydraulic characteristics that dominate the fish passage efficiency. Thus, it is crucial to find out the weir operation rule for properly sustaining efficient fish-passage, such as the optimized flowrate. In this study, the FLOW-3D was used to analyze and compare the various hydraulic characteristics associated with the passage efficiency, based upon the given different flowrate, and subsequently provide the optimized flowrate for the fishway movable weir to maintain the best efficient flow condition for the fish-passage.

• The KSFM Journal of Fluid Machinery
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• v.11 no.5
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• pp.22-29
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• 2008

This study is performed to understand the effect of the variation in the passage area of a two-dimensional impeller on its performance characteristics. We observe the results with changing the area ratio of inlet to outlet about $1{\sim}2.8$. A comparison between the experimental and numerical results was performed for the same configuration in order to verify the reliability of the CFD code. Overall characteristics in the passages of impeller were analyzed in detail including streamline, Mach number, pressure and polytropic efficiency distribution. When the passage area ratio exceeds 2, the pressure ratio is high. An area ratio of 2.3 showed the highest efficiency. The results will be used as useful reference data to establish the design concept of two-dimensional impeller and to improve its performance.

• The KSFM Journal of Fluid Machinery
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• v.18 no.2
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• pp.5-13
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• 2015

The aim of this study is to investigate the feasibility of a new type of casing for the inline Francis hydro turbine. Comparing with the traditional turbine with spiral casing, this turbine is unique for its flow passage shape at the first stage of flow to the turbine, very similar to a pipe, called inline casing. Before the commercialization of this new type of casing, a global investigation of the inline casing must be conducted. Preserving the structural characteristics of simple, compact-size and convenient for manufacture, different shapes of the belt passage, vertical corner and stay vanes are applied to investigate the influence of flow passage shape on the turbine performance. Stable and relatively high efficiency is achieved regardless of flow passage shape difference proving the feasibility of the inline casing used in a hydro turbine.

• Journal of Korean Port Research
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• v.14 no.1
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• pp.27-35
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• 2000

In Pusan Harbour, new port development projects are implemented such as the Extended Terminal adjacent to the Gamman Terminal, Pusan New Port, the Navy $\bigcirc$$\bigcirc$ piers, etc. which will require new marine traffic environments in the Passage I of Pusan Harbour. Specially, the turning basin of the Extended Terminal adjacent to the Gamman Terminal has been designed to overlay the Passage I of Pusan Harbour, which will interrupt the inbound traffic flow and the results will be worried to decrease the efficiency of port operation. Therefore, this paper will be aimed to evaluate the traffic congestion in the Pusan Passage I due to the opening of new ports within Pusan Harbour in 2006 and 2011 by using computer simulation based the queueing theory.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2989-2994
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• 2008

The shopping center in underground passage for efficient space utilization is increased in urban area. This study describes operation characteristics of HVAC systems with ventilation and individual heating and cooling unit for shopping center in underground passage. In order to compare energy saving, thermal environment and installation space, etc., an integrated simulator with heat production and distribution system was designed and constructed. Energy delivery efficiency is improved over 20%, and energy saving of the hybrid system is calculated as over 30% compared to conventional all air type in the case of heating. And also the results showed that humidity decreased about $5{\sim}6%$, also characteristics of thermal control is improved over 34%.

• The KSFM Journal of Fluid Machinery
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• v.12 no.2
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• pp.8-16
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• 2009

The objective of this study is to investigate the three-dimensional turbulence flow characteristics of a rotor passage of an one-stage axial flow gas turbine and to investigate the effects of a boundary layer fence installed on the hub endwall of the rotor passage. Secondary flows occurring within the rotor passage (e.g. horseshoe vortex, passage vortex, and cross flow) cause secondary loss and reduce turbine efficiency. To control these secondary flows, a boundary layer fence measuring half the height of the thickness of the inlet boundary layer was installed on the hub endwall of the rotor passage. This study was performed numerically. The results show that the wake and secondary flows generated by the stator reduced the rotor load to constrain the development of cross flow and secondary flow reinforced by the rotor passage. In addition, the secondary vortices occurring within the rotor passage were reduced by the rotation of the rotor. Although, the boundary layer fence induced additional vortices, giving rise to an additional loss of turbine, its presence was shown to reduce the total pressure loss when compared to effects of the case without fence regardless of the relative position of blades by enervating secondary vortices occurred within the rotor passage.

• The KSFM Journal of Fluid Machinery
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• v.18 no.5
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• pp.19-25
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• 2015

As a core component of a hydropower station, hydro turbines play a vital role in the integration of a power station. Research on the technology of hydro turbine is continuously increasing with the development of water electricity. On the basis of one-dimensional loss analysis, for three-dimension design, there are a lot of dimension of the internal flow passage shapes that are determined by experience. Therefore, the effect of the internal flow passage shapes on the performance and internal flow characteristics of a Francis hydro turbine model is investigated in this study. In this study, the small curvature of runner blade trailing edge shape is good for improving the efficiency of Francis turbine. The straight stay vane leading edge is good for suppressing the secondary flow. Moreover, suitable tongue passage shape and stay vane number improve the performance of the turbine considerably.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.91-99
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• 1999

In Pusan Harbour, new port development projects are implemented such as the Extended Terminal adjacent to the Gamman Terminal, Pusan New Port, the Nary $\infty$ piers, etc. which will require new marine traffic environments in the Passage I of Pusan Harbour Specially, the turning basin of the Extended Terminal adjacent to the Gamman Terminal gas been designed to overlay the Passage I of Pusan Harbour, Which will interrupt the inbound traffic flow and the results will be worried to decrease the efficiency of port operation. Therefore, this paper will be aimed to evaluate the traffic congestion in the Pusan Passage I due to the opening of new ports within Pusan Harbour in 2006 and 2011 by using computer simulation based the queueing theory.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.230-231
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• 2023

This study proposes a deep reinforcement learning-based algorithm to automatically generate a ship's passage plan. First, Busan Port and Gwangyang Port were selected as target areas, and a container ship with a draft of 16m was designated as the target vessel. The experimental results showed that the ship's passage plan generated using deep reinforcement learning was more efficient than the Q-learning-based algorithm used in previous research. This algorithm presents a method to generate a ship's passage plan automatically and can contribute to improving maritime safety and efficiency.