• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.691-696
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• 2004

Recently, it is required that the automotive air conditioning system must keep the cabin temperature comfortable in spite of engine speed, and Improve the fuel consumption during all the seasons. To satisfy these requirements, the variable displacement swash plate type compressor with control pressure valve is developed. In this study, the effects of two type valves, suction pressure control valve and differential pressure control valve, on the performance of swash plate type compressor has been investigated experimentally.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.8
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• pp.756-761
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• 2004

Since the use of CFC and HCFC refrigerants are to be restricted due to the depletion of ozone layer, this experiment applies the NH$_3$ gas to study the performance characteristics from the superheat control for improving the energy efficiency. The experiments are carried out for the condensing pressure of refrigeration system from 14.5 bar to 16.0 bar by 0.5 bar and for superheat temperature from $0^{\circ}C$ to 1$0^{\circ}C$ by 1$^{\circ}C$ at each condensing pressure. As a result of experiment, when the superheat temperature is 1$^{\circ}C$ at each condensing pressure, the refrigeration system has the highest performance.

• Nuclear Engineering and Technology
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• v.36 no.1
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• pp.73-82
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• 2004

The deaerator of a power plant is one of feedwater heaters in the secondary system, and it is located above the feedwater pumps. The feedwater pumps take the water from the deaerator storage tank, and the net positive suction head(NSPH) should always be ensured. To secure the sufficient NPSH, the deaerator tank is equipped with the level control system of which level sensors are critical items. And it is necessary to ascertain the sensor state on-line. For this, a model-based fault detection and diagnosis(FDD) is introduced in this study. The dynamic control model is formulated from the relation of input-output flow rates and liquid-level of the deaerator storage tank. Then an adaptive state estimator is designed for the fault detection and diagnosis of sensors. The performance and effectiveness of the proposed FDD scheme are evaluated by applying the operation data of Yonggwang Units 3 & 4.

• Journal of Power System Engineering
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• v.20 no.5
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• pp.78-85
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• 2016

This paper considers the influence of internal heat exchangers to the efficiency of a refrigerating system using R170. These liquid-gas heat exchangers(internal or suction-line heat exchangers) can, in some cases, yield improved system performance while in other cases they degrade system performance. A steady state mathematical model is used to analysis the performance characteristics of refrigeration system with internal heat exchanger. The influence of operating conditions, such as the mass flowrate of R170, inner diameter tube and length of internal heat exchanger, to optimal dimensions of the heat exchanger is also analyzed in the paper. The main results were summarized as follows : the mass flowrate of R170, inner diameter tube and length of internal heat exchanger, and effectiveness have an effect on the cooling capacity, compressor work and RCI(Relative Capacity Index) of this system. Exception for the effect of inner diameter, the RCI of R170 with respect to refrigerant mass flowrate, the length and effectiveness of internal heat exchanger is about 2.1~3.3% higher than that of R13 at the same experimental conditions. With a thorough grasp of these effect, it is necessary to design the R170 compression refrigeration cycle using internal heat exchanger.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.1
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• pp.88-94
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• 2021

Currently, the Busan cooperative fish market follows a traditional market style. This study first investigates the current conditions and environment of the market, and to modernize the market, it proposes a new automatic unloading system based on the benchmark of Namhae Suhyup. In this system, a Korean-type suction fish vacuum pump is employed to increase the loading time. An automatic grader with an adjusting device for inclined angles and a weighing machine with an automatic alignment device are proposed. In addition, a folding machine is employed to prepare boxes. The specifications for each subsystem are provided. By implementing this system, the freshness of fish can be maintained and the sellers can earn more. This system can also be applied to the cooling system of the fish reservoir of littoral sea fishing boats.

• Ocean Systems Engineering
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• v.1 no.2
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• pp.157-169
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• 2011

To provide more rational design solutions at conceptual design level, axiomatic design method has been applied to solve critical part of a new engineering problem called Mobile Harbor. In the implementation, the Mobile Harbor, a functional harbor system that consists of a vessel with container crane approaches to a container ship anchored in the open sea and establishes a secure mooring between the two vessels to carry out loading and unloading of containers. For this moving harbor system to be able to operate successfully, a reliable and safe strategy to moor and maintain constant distance between the two vessels in winds and waves is required. The design process of automatic ship-to-ship mooring system to satisfy the requirements of establishing and maintaining secure mooring has been managed using axiomatic design principles. Properly defining and disseminating Functional Requirements, clarifying interface requirements between its subsystems, and identifying potential conflict, i.e. functional coupling, at the earliest stage of design as much as possible are all part of what need to be managed in a system design project. In this paper, we discuss the automatic docking system design project under the umbrella of KAIST mobile harbor project to illustrate how the Axiomatic Design process can facilitate design projects for a large and complex engineering system. The solidified design is presented as a result.

• The KSFM Journal of Fluid Machinery
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• v.17 no.4
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• pp.40-46
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• 2014

This paper describes blower performance characteristics of a automated vacuum waste collection system. Blowers serially connected to six or seven centrifugal blowers are evaluated by experimental measurements to understand blower performances according to blower numbers operated. Two different blowers and duct diameters connected to the main blowers are considered. Data acquisition system is introduced to measure pressure and pressure difference at the main duct simultaneously, which is connected to several blowers serially. A auxiliary blower, which is installed between a filter room and an air deodorizing apparatus, is also added to simulate its performance effect on the main blower. Throughout the experimental measurements of the blower system, it is found that pressure and inlet velocity at the upstream of a blower increase 3.7 and 2.4 times separately by increasing the operating blower numbers from one to seven. It is noted that blower efficiency and pressure measured at the system vary according to the distance between a air intake and a blower system. Auxiliary blower is effective to increase blower inlet suction pressure, while total energy consumption is increased relatively.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.2
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• pp.304-310
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• 2001

This paper describes the analysis of flow field using a projection finite element method. The projection scheme with a pressure correction is presented for the analysis of an incompressible Navier-Stokes flow. The projection scheme is analyzed numerically and applied to the well-known bench marking problems such as lid driven cavity. Finally, the projection scheme is applied to a flow through the automobiles front. In the automobiles cooling system, the flow through its front is very important to a cooling performance. The results show that the flow quantity increases by locating the position of bumper to the further front position of a car. And, the improvement on the suction part below a bumper achieves the more passing flow quantity. The attachment of an air dam increases passing flow quantity causing the pressure rise to the front part and the pressure drop beneath a car.

• The KSFM Journal of Fluid Machinery
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• v.2 no.3 s.4
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• pp.24-29
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• 1999

The ASME strainers have been newly installed at the suction side of each reactor coolant pump to get rid of the foreign materials which may damage the pump impeller or interfere with the coolant path of fuel flow tube or primary plate type heat exchanger. The strainer was designed in accordance with ASME SEC. III, DIV. 1, Class 3 and the structural integrity was verified by seismic analysis. The screen was designed in accordance with the effective void area from the result of flow analysis for T-type strainer. After installation of the strainer, it was confirmed through the field test that the flow characteristics of primary cooling system were not adversely affected. The pressure loss coefficient was calculated by Darcy equation using the pressure difference through each strainer and the flow rate measured during the strainer performance test. And these are useful data to predict flow variations by the pressure difference.

• Journal of Power System Engineering
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• v.3 no.4
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• pp.28-35
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• 1999

An application of scroll compressor to the residential air conditioning and heat pump markets has generated many reliability problem, especially abnormal noise. Most of these noise problems is due to the check valve and compliance between FS(Fixed Scroll) and OS(Orbiting Scroll). FS and OS are the main parts of scroll compressor and are the main pumping part. But check valve has the role of protection of reverse rotation of OS when power is off. Check valve have several noise problems. Among them, shut down noise and valve movement noise is more than severe than any other problem. In this paper covers with these two noise problem.