• 한국음향학회:학술대회논문집
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• 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
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• pp.662-667
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• 1994

This paper presents the design and construction details of a soundproof enclosure for housing 20 KVA diesel generator-set. As the generator had to be installed close to the hospital building, it was desirable to reduce the transmission of noise by housing the generator in such an enclosure. The diesel engine being an air cooled one, it was essential to supply fresh air into the enclosure for its cooling. Forced inflow of air is provided through an inlet duct located in such a way that the incoming fresh air is thrown close to the inlet of cooling fan of the engine. The high velocity air stream, which heats up while passing over the engine head, escapes to the atmosphere through a rectangular outlet duct with enlarges inlet that receives hot air from the engine. The air ducts were designed specially and have been provided with acoustic lining for sound absorption. The masonary enclosure has been provided with double glazed fixed windows and double doors. The exhaust pipe of the engine fitted with a muffler has been taken out through the enclosure wall facing away from the hospital. Acoustic performance studies conducted in terms of attenuation provided by the enclosure at different frequencies have also been presented and discussed. The noise control measures adopted for building the sound-proof enclosure have been found to be quite effective as the noise levels inside the hospital building are now within the acceptable limits.

• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2435-2443
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• 2022

The once-through steam generator used in the small modular reactor needs to consider the stability of the outlet steam pressure and steam superheat of the secondary circuit to achieve better operating efficiency. For this reason, this paper designs a controllable operation scheme for the steam pressure and superheat of the small reactor once-through steam generator. On this basis, designs a variable universe fuzzy controller, first, design the fuzzy control rules to make the controller adjust the PI controller parameters according to the change of the error; secondly, use the domain adjustment factor to further subdivide the input and output domain of the fuzzy controller according to the change of the error, to improve the system control performance. The simulation results show that the operation scheme proposed in this paper have better system performance than the original scheme of the small reactor system, and controller proposed in this paper have better control performance than traditional PI controller and fuzzy PI controller, what's more, the designed control system also showed better anti-disturbance performance in lifting experiment between 100% and 80% working conditions. Finally, the experimental platform formed by connecting the digital small reactor with Matlab/Simulink through OPC(OLE for Process Control) communication technology also verified the feasibility of the proposed scheme.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.782-787
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• 2001

An optimum thermal design analysis of the combined cycle power plant with triple pressure heat recovery steam generator was performed by the numerical simulation. The optimum design module used in the paper is DNCONF, a function of IMSL Library, which is widly known as a method to search for the local optimum. The objective function to be minimized is the cost of total power plant including the steam turbine power enhancement premium. The result of this paper shows that the cost reduces if the design point of power plant becomes the local optimum, and many calculations at various initial conditions should be carried out to get the value near the global optimum.

• 대한전자공학회논문지
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• 제27권6호
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• pp.963-971
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• 1990

This paper proposes a memory intensive VLSI architecture for the realization of real-time 3x3 neighborhood processor based on the distributed arithmetic. The proposed architecture is characterized by a bit serial and multi-kernel parallel processing which exploits the pixel kernel parallelism and concurrency. The chip implements 8 neighborhood processing elements in parallel with efficirnt input and output modules which operate concurrently. Besides the a4chitectural design of a neighborhood processor, the design methodology using module generator concept has been considered and MOGOT(MOdule Generator Oriented VLSI design Tool) has been constructed based on the workstation. Based on these design environments MOGOT, it has been shown that the main part of the suggested architecture can be designed efficiently using 2\ulcorner double metal CMOS technology. It includes design of input delay and data conversion module, look-up table for inner product operation, carry save accumulator, output data converter and delay module, and control module.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1219-1224
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• 2004

In this study the optimization of plate-fin type heat sink with vortex generator for thermal stability is conducted numerically. To acquire the optimal design variables, the CFD and mathematical optimization are integrated. The flow and thermal fields are predicted using the finite volume method. The optimization is carried out by means of the sequential quadratic programming (SQP) method. The results show that when the temperature rise is less than 40 K, the optimal design variables are as follows; $B_1=2.584mm$, $B_2=1.741mm$, and t = 7.914 mm. Comparing with the initial design, the temperature rise is reduced by 4.2 K, while the pressure drop is increased by 9.43 Pa. The Pareto optimal solutions are also presented between the pressure drop and the temperature rise.

• 대한전자공학회논문지SD
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• 제45권12호
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• pp.83-88
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• 2008

QPP 인터리버는 고속 병렬 터보 디코더에서 메모리 경합 없는 인터리빙 기능을 제공할 수 있어 주목을 받고 있다. 본 논문에서는 QPP 인터리버의 주소 생성 함수 $f(x)=(f_1x+f_2x^2)%K$의 이차항 $f_2x^2%K$가 아주 작은 주기를 갖는다는 것을 보이고, 이러한 주기성을 이용하여 설계한 저전력 주소 생성기를 소개한다. 소개한 주소 생성 방법에서는 처음 반주기 동안의 $f_2x^2%K$ 값들을 메모리에 저장하고 이 값들은 읽어 f(x)를 계산함으로써 $f_2x^2%K$값들의 계산 없이 주소를 생성한다. 이렇게 설계한 주소 생성기는 일반적인 방법에 의한 설계에 비하여 평균 5.54%(가변 K인 경우)와 27.38%(고정 K인 경우)의 전력 소모 절감 효과를 갖는다.

• 한국해양환경ㆍ에너지학회지
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• 제17권2호
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• pp.146-152
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• 2014

선형발전기와 연성된 원통형 부이의 수직운동으로부터 파랑에너지를 추출하는 파력발전장치의 설계과정을 소개하였다. 최대 파워는 최적조건($c_{PTO}=b_T$, ${\omega}={\omega}_N$)에서 발생하며, 공진조건시 부이의 수직운동 고유주파수와 속도스펙트럼의 피크 주파수를 일치시키지 않고 의도적으로 고유주파수를 15% 크게 설정하면 추출파워의 최대값을 더욱 높일 수 있다. 이러한 방법을 통하여 추출 파워의 증가와 함께 부이의 흘수를 낮추고 동시에 PTO 감쇠력을 줄일 수 있기 때문에 발전장치 제작 비용을 낮출 수 있는 부수적인 효과를 얻을 수 있었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.93-96
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• 2011

액체로켓엔진의 최적화를 위해 유전알고리즘을 사용하여 주요 설계변수인 연료와 산화제의 질유량과 연소실 압력을 결정하였다. 대상엔진은 LO2/RP-1을 추진제로 사용하는 개방형 가스발생기 사이클을 대상으로 하였다. 최적설계의 목적함수는 비추력의 최대화이고 펌프-터빈의 에너지 발란스와 요구추력을 제한조건으로 하였다. 연소실의 물성치는 CEA2를 이용하였으며 펌프 및 터빈의 효율, 가스발생기 및 예연소기의 물성치는 문헌 자료를 수학적으로 모델링 하였다. 가스발생기 사이클 계산 결과 참고문헌과 비교하여 비추력에서 약 3~4%, 펌프파워에서 2~6%의 오차를 보였다.

• Journal of Power Electronics
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• 제17권2호
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• pp.542-550
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• 2017

Aiming at the deficiencies of power sharing control performances when a traditional droop control is adopted for microgrid inverters, this paper proposes a microgrid inverter power sharing control strategy based on a virtual synchronous generator. This control method simulates the electromechanical transient characteristics of a synchronous generator in a power system by an ontology algorithm and the control laws of a synchronous generator by control over the speed governor and excitation regulator. As a result, that the microgrid system is able to effectively retain the stability of the voltage and frequency, and the power sharing precision of the microgrid inverter is improved. Based on an analysis of stability of a microgrid system controlled by a virtual synchronous generator, design thoughts are provided for further improvement of the power sharing precision of inverters. The simulation results shows that when the virtual synchronous generator based control strategy was adopted, the power sharing performances of microgrid inverters are improved more obviously than those using the droop control strategy.

• 한국유체기계학회 논문집
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• 제16권3호
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• pp.32-38
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• 2013

This paper deals with the study on the rotordynamic and experimental analysis of turbine-generator system connected with a magnetic coupling. Although magnetic coupling has been used to torque transmission of chemical processing pump rotating at under 3,600rpm, magnetic coupling in this study is applied to high-speed turbine-generator system using a working fluid that is refrigerant such as ammonia or R-124a. Results of rotordynamic design analysis are as follows. The first, shaft diameter nearest to outer hub of magnetic coupling has a big effect on the $1^{st}$ critical speed of generator rotor. The second, if the $1^{st}$ critical speeds of turbine rotor and generator rotor have enough to separation margin in comparison to rated speed, the $1^{st}$ critical speed of turbine-magnetic coupling-generator rotor train has enough to separation margin regardless of connection stiffness of magnetic coupling. The analytical FE model is guaranteed by impact test on the prototype and condition monitoring such as measurements of vibration and bearing temperature is also performed.