• Journal of Drive and Control
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• v.16 no.4
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• pp.93-100
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• 2019

Nuclear and thermal power plants must provide the turbines with an appropriate degree of high temperature and high pressure steam, to produce the optimum electricity. Additionally, in the event of system and power system failure during electrical production, the steam is immediately disabled, to protect the turbines and generators rotating at high speed. The plant thus uses a special steam control valve system for turbine control, which is opened by force of the hydraulic servo actuator and closed by a large steel spring force. In this study, the causes of failure of the turbine control valve system, a key device of the power plants, were analyzed, and the causes of failure were improved relative to reliability of the equipment.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.9
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• pp.671-678
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• 2012

The objective of this study is to analyze theoretically the performance of an open air-cycle refrigeration system in which environmental concerns increase. The pressure ratio of the external compressor and efficiencies of the components that compose of the system are selected as important parameters. As the pressure ratio of the external compressor increases, the pressure ratio of the ACM compressor is determined high, the refrigerating temperature and capacity increase, the COP decreases, and the total entropy production rate increases. The effect of heat exchanger effectiveness and turbine efficiency on the performance are greater than that of the ACM compressor efficiency. Also the performance of the air-cycle refrigeration system with two heat exchangers has been enhanced like high COP and low total entropy production rate, compared to the system with one heat exchanger.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.161-164
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• 2008

For the development of solar thermal power tower plant from the early 80' to today, various kinds of receiver have been tested and evaluated. Most of 1st generation receiver used water/steam as a working fluid to operate steam turbine and now the first commercial solar power tower PS-10 also makes saturated steam. However, to increase thermal efficiency of storage system and to obtain practical use of solar energy, molten salt system have been used from THEMIS project in France at 1984. The Solar Tres plant of 17 MWe power generation will be constructed in Spain and have plan to operate 24 hours in summer. The air volumetric receiver system can be integrated with combined cycle of gas turbine and HRSG and also with steam turbine easily. Therefore, related researches to develop higher efficient solar power tower plant and to operate with stable are widely performed in the world.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.4
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• pp.82-91
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• 1997

In this paper, a design method of the boiler-turbine control system in the coal fired power plant is proposed. We need to control electric output and drum pressure and water level in drum to guarantee stable operation and save energy for generating electricity and decrease air pollution in the boiler-turbine system. This boiler-turbine control system is composed of reference model part and model following part. The multivariable boiler-turbine system is separated into 3 SISO(Single Input Single Output) systems applying the concept of relative gain matrix. Each 3 reference models for separated boiler-turbine system are composed of 1st order nominal plant and hysteresis integral control system and they make good dy¬namic response with no overshoot and fast rising time. Each fuzzy controller to follow as close as possible to the response of each reference model is designed. The robustness and the good tracking property can be achieved using 5150 fuzzy controllers when there are modeling errors, disturbances and parameter pertur¬bations. The effectiveness of the proposed design method is verified through simulations.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.9
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• pp.835-841
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• 2010

The design of the fuel injector is one of the important operating factors that determine the extent of mixing of air and fuel in an MEMS gas turbine engine. In this study, we consider a system with three inlet ports with each port having multiple injectors. We perform a parametric study by varying the arrangement of fuel injectors and difference of ratio of fuel supply. The results are presented in terms of the premixed flow distribution and equivalence ratio.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.464-469
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• 2012

In the electric power plant, the shaft vibration is one of the very important point for successful long-term operation, because the high reliability unit needs stable rotor dynamic system. However, in the one combined cycle power plant, the abnormal high level shaft vibration analyzed 1 X on the journal bearing has been several times suddenly tripped of Gas turbine due to the accumulated oil carbide. This paper describes how to countermeasure the abnormal shaft vibration in the journal bearing of Gas turbine exhaust bearing in the field.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.2
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• pp.111-117
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• 2012

Oscillating water column is the most widely used ocean energy converting systems all over the world. The operating performance is influenced by the efficiencies of the two converting stages in the OWC chamber-turbine integrated system. In order to consider the effects of the turbine, the orifice model are carried out. The VOF based Numerical Wave Tank (NWT) is utilized to simulate the water column oscillation inside the chamber and the results are compared with corresponding experimental data. This paper reviews the state of the art in interaction among wave elevation inside the chamber and air flow rate in the duct, which are considered the turbine effects. Effects of incident wave conditions and several shape parameters on the operating performance of OWC chamber are investigated numerically. The effects of the impulse turbine on the integrated system and interaction among the wave elevation, pressure and air flow velocities variations are investigated.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.6 s.237
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• pp.722-729
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• 2005

Design analysis of the solid oxide fuel cell and gas turbine combined power system is performed considering different methods for preheating cell inlet air. The purpose of air preheating is to keep the temperature difference between cell inlet and outlet within a practical design range thus to reduce thermal stress inside the cell. Three different methods considered are (1) adopting a burner in front of the cell, (2) adopting a preheater (heat transfer from the main combustor) in front of the cell and (3) using recirculation of the cathode exit gas. For each configuration, analyses are carried out for two values of allowable maximum cell temperature difference. Performance characteristics of all cases are compared and design limitations are discussed. Relaxation of the cell temperature difference (larger difference) is proved to ensure higher efficiency. Recirculation of the cathode exit gas exhibits better performance than other methods and this advantage becomes more prominent as the constraint of the cell temperature difference becomes more severe (smaller temperature difference).

• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.301-310
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• 2003

Eco-Machinery engineering technologies in KIMM for reducing NOx emission were introduced. Combustion technologies such as reburning and fuel staged or air staged combustion have been applied to reduce NOx emission in the field of boiler furnaces. Lean premixed combustion method have been studied in gas turbine combustor. Hybrid system with plasma and SCR being considered as prospective method of De-NOx has been developed. Also, low NOx technologies including common rail system, EGR and DPF in diesel engine have been investigated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.6
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• pp.413-420
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• 2011

Thermodynamic cycles using binary mixtures as working fluids offer a high potential for utilization of low-temperature heat sources. This paper presents a thermodynamic performance analysis of Goswami cycle which was recently suggested to produce power and cooling simultaneously and combines the Rankine cycle and absorption refrigeration cycle by using ammoniawater mixture as working fluid. Effects of the system parameters such as concentration of ammonia and turbine inlet pressure on the system are parametrically investigated. Results show that refrigeration capacity or thermal efficiency has an optimum value with respect to ammonia concentration as well as to turbine inlet pressure.