• Transactions of the Korean Society of Automotive Engineers
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• 제21권2호
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• pp.87-97
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• 2013

Recently the use of gas spring in the combat and commercial vehicle's suspension is increasing. Because of its nonlinear characteristics, the gas spring can support wide range of dynamic loads and gives good ride quality. In design of gas spring, isothermal and adiabatic processes are applied generally, but those processes could not produce heat transfer effect in the simulation. So in this study, heat transfer differential equation and BWR/Ideal state equation are used to calculate the pressure of gas spring which is changing with time. The numerical analysis showed that the pressure of gas spring forms a hysteresis loop in the both of the state equations. But the peak pressure value of BWR equation over 0.1Hz frequency are higher than that of adiabatic process. And the test results showed that the differences between test results and ideal gas equation are smaller than those of BWR equation, so the ideal equation is more accurate than BWR equation in this case.

• Nuclear Engineering and Technology
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• 제22권4호
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• pp.359-370
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• 1990

This study concerns with comparing low-dimensional reactor kinetics methods with a three-dimensional kinetics method to be used for safety analysis of light water reactors in order to suggest means of preparing input parameters required for low-dimensional methods. For this purpose a one-dimensional finite difference two-group diffusion theory code ODTRAN and a third-order Hermit polynomial-based point kinetics code POTRAN are developed and used to obtain low-dimensional solutions to the LRA-BWR kinetics benchmark problem. The results are compared with a three-dimensional modified Borresen's coarse-mesh solution of the kinetics problem by CMSNACK code. Through this comparison some simple but practical means of preparing input parameters of low-dimensional kinetics analysis methods are suggested.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2000년도 추계학술발표회 논문집
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• pp.148-151
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• 2000

• Journal of the Korean Institute of Gas
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• 제1권1호
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• pp.41-48
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• 1997

The equation of state is widely utilized as a simple model for the prediction of gas properties. There are several equations of state and they often make diverse and hard to believe output of gas properties. In this study, We show a reliability of equation of state for nitrogen, oxygen and argon in pressure range from 1 bar to 30 bar and temperature range from liquefaction to room temperature. We use three equations of state such as Soave-Redlich-Kwong, Peng-Robinson and BWR-LS' equation of state which provided in the Aspen plus. The results were compared with literatures and virial equation. Finally, We report the differences of process calculation of distillation column and expansion turbine in cryogenic air separation plant with change of equation of state.

• Applied Chemistry for Engineering
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• 제7권3호
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• pp.443-452
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• 1996

Fouling is caused by sedimentation and corrosion of polymer, heavy paraffine, chemicals, heavy organics, asphaltene, etc. in the entire chemical process of heat exchanger, boiler, desalter, etc. Fouling phenomena remains a serious operating problem which results in increased energy consumption, increased pressure drops, reduction or complete loss of products yield, and increased maintenance costs. In order to calculate the separated amounts of foulants and to control the fouling process, the predictive model is developed which is based on Scott & Magat polymer solution theory, Peng-Robinson EOS, BWR EOS, and continuous and multicomponent thermodynamics.

• Nuclear Engineering and Technology
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• 제17권4호
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• pp.247-255
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• 1985

This paper describes a new method for the design of variable structure model-following control systems(VSMFC). This design concept is developed using the theory of variable structure systems (VSS) and slide mode. The new results are presented on the sliding control methodology to achieve accurate tracking for a class of nonlinear, multi-input multi-output(MIMO), time varying systems in the presence of parameter variations. The design requires little computational effort. The dynamic response is insensitive to parameter variations. The feasibility and the advantages of the method are illustrated by applying it to a 1000 MWe boiling water reactor(BWR). The control is studied in the range of 85%∼90% of rated power for load-following control. A set of 12 nonlinear differential equations is used to simulate the total plant. A 6-th order linear model has been developed from these equations at 85% of rated power. The obtained controller is shown by simulations to be able to compensate for a plant parameter variation over a wide power range.