• 설비공학논문집
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• 제16권12호
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• pp.1126-1133
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• 2004

This paper presents an experimental measurement of effective thermal conductivity in an adsorbent packed bed with silica gel A type. The effective thermal conductivity was measured under different conditions of the adsorbent bed temperature, pressure, particle size and water content by using the transient hot wire method. The measured effective thermal conductivity showed to become bigger with decreasing particle size or increasing water content, but it was a little affected with increasing bed temperature and pressure. The bed temperature was varied in the range of 1$0^{\circ}C$ (equation omitted) T (equation omitted) 5$0^{\circ}C$ and the pressure in the range of 10 kPa (equation omitted) P (equation omitted) 190 kPa. The results show that 0.10～0.18 W/mㆍK of effective thermal conductivity measured for the zero water content.

• 대한설비공학회지:설비저널
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• 제13권1호
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• pp.5-13
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• 1984

This analysis of numerical procedure is prediction of laminar flow and heat transfer at two dimension and steady flow in asymmetric sudden expansion channel. At former study, to analyse the flows with separation, the full Navier-Stokes equation is used, but there are many difficulties to analyse, and although significant progress has been made in the development of efficient computational methods for the Navier-Stokes equations, very large computation times are still required. In case of reward-facing flow, boundary-layer equation is used instead of full Navier-Stokes equation to analyse velocity fields, and result of this numerical analysis is good agreement with the given experimental study. In this case, since the computer time required for the boundary-layer calculation is an order of magnitude less than required for the solution of the full Navier-Stokes equation, this boundary-layer model provides a good approximate solution.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 유기절연재료 방전 플라즈마연구회
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• pp.69-72
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• 2003

This paper describes the information for the difference between two-term and multi-term approximation of the Boltzmann. In previous paper, we calculated the electron transport coefficients in pure Oxygen and Argon gases by using two-term approximation of Boltzmann equation. Therefore, in this paper, we calculated the electron transport coefficients(W and $N{\cdot}D_L$) in pure Oxygen and Argon gases for range of E/N values from 0.01~500[Td] at the temperature was 300[K] and pressure was 1[Torr] by using multi-term approximation of the Boltzmann equation by Robson and Ness, The results of two-term and multi-term approximation of the Boltzmann equation has been compared with the experimental data for a range of E/N.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 유기절연재료 방전 플라즈마연구회
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• pp.73-76
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• 2003

This paper describes the information for quantitative simulation of weakly ionized plasma. In previous paper, we calculated the electron transport coefficients in pure Xenon gas by using two-term approximation of Boltzmann equation. Therefore, in this paper, we calculated the electron transport coefficients(W, $N{\cdot}D_L$ and $D_{L/{\mu}}$) in pure Xenon gas for range of E/N values from 0.01 ~ 500[Td] at the temperature was 300[K] and pressure was 1[Torr] by using multi-term approximation of the Boltzmann equation by Robson and Ness, The results of two-term and multi-term approximation of the Boltzmann equation has been compared with the experimental data by L. S. Frost and A. V. Phelps for a range of E/N.

• 한국안전학회지
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• 제22권2호
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• pp.47-52
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• 2007

The flash points and the fire points for the m-xylene+n-propionic acid and n-butanol+n-pentanol systems were measured by using Tag open-cup apparatus(AS1M D 1310-86). The experimental flash points of two binary systems were compared with the values calculated by the Raoult's law, Van Laar equation and Wilson equation. The calculated values based on the Raoult's law on m-xylene+n-propionic acid system were found to be better than those based on Van Laar and Wilson equations. The calculated values based on Van Laar equation on n-butanol+n-pentanol system were found to be better than those based on the Raoult's law and Wilson equation. The the fire points for the m-xylene+n-propionic acid system were about $7{\sim}8^{\circ}C$ above the flash points. In the case of n-butanol+n-pentanol system, the flash points and the fire points had been found to be identical.

• 대한기계학회논문집A
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• 제23권11호
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• pp.2007-2013
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• 1999

A Newly proposed control methodology applied to the aeroelastic system experiencing flutter is investigated and its performance is verified experimentally. The flexible cantilever beam slicked with piezofilm sensor and piezoceramic actuator is modelled in physical domain. Dynamic moment equation for the system is derived via Ito's stochastic differential equation and F-P-K equation. Also system's characteristics in stochastic domain is analyzed simultaneously. LQG controller is designed and used in physical and stochastic domain. It is shown experimentally that the vibration of beam is controlled effectively by designed LQG controller in physical domain. By comparing the result with that of LQG controller designed in stochastic domain, it is shown that the new control method, called Heo-stochastic control technique, has better performance as a controller.

• 대한조선학회논문집
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• 제48권3호
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• pp.200-206
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• 2011

The mechanical properties of the most widely used cryogenic materials, i.e. austenitic stainless steel (ASS), aluminum alloy and invar steel, strongly depend on temperatures and strain rates. These phenomena show very complicated non-linear behaviors and cannot be expressed by general constitutive equation. In this study, an unified constitutive equation was proposed to represent the effect of temperature and strain rate on the materials. The proposed constitutive equation has been based on Tomita/Iwamoto and Bodner/Partom model for the expression of 2nd hardening due to martensite phase transformation of ASS. To simulate ductile fracture, modified Bodner/Chan damage model was additionally applied to the model and the model validity was verified by comparison of experimental and simulation results.

• 대한토목학회논문집
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• 제26권4B호
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• pp.371-378
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• 2006

본 연구에서는 만곡수로에서 주 흐름방향에 따라 변화하는 2차류의 거동을 이론적으로 예측하기 위해 Odgaard(1986) 및 Chang(1988)의 제안을 바탕으로 새로운 방정식을 유도하였다. 개발된 이론식은 2차류의 횡방향 유속을 주 흐름 및 연직방향의 함수로 표현한다. 이를 검증하기 위해 실험실에 사행도가 각기 다른 두 개의 만곡수로를 제작하여 수리실험을 수행하였다. 수리실험결과를 제안된 이론식 및 기존 식과 비교해 보면, 제안된 식은 실측치에 잘 일치하는 반면 기존 식은 과대 산정하는 경향이 있었다. 제안된 이론식을 통해 수리량이 변화는 경우 2차류가 어떻게 변하는지를 확인해 본 결과, 사행도, 조도, 하폭 대 수심비가 클수록 2차류는 증가하였다. 또한 조도 및 하폭 대 수심비의 변화에 따라 2차류의 흐름방향 분포가 민감하게 반응하였다.

• 설비공학논문집
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• 제27권1호
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• pp.8-13
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• 2015

The objective of this paper is to provide design data of fin-tube heat exchanger which have a large diameter oval tube for dryer application. In this study, the heat transfer and pressure drop performance characteristics of the fin-tube heat exchanger were compared with Dittus-Boelter and a new correlation equation using Wilson plot method. The simulation results based on section by section method were compared with experimental results. These results showed that a new correlation equation using Wilson plot method provided better prediction, about 3 to 12%, than the Dittus-Boelter equation, from the experiment comparison. Also, the pressure drop of simulation results showed much more deviation with the experimental results.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2000년도 추계학술대회 학술발표 논문집
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• pp.281-286
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• 2000

This paper describes a lateral guidance system of an unmanned vehicle, using a neural network model of magneto-resistive sensor and magnetic fields. The model equation was compared with experimental sensing data. We found that the experimental result has a negligible difference from the modeling equation result. We verified that the modeling equation can be used in the unmanned vehicle simulations. As the neural network controller acquires magnetic field values(B$\_$x/, B$\_$y/, B$\_$z/) from the three-axis, the controller outputs a steering angle. The controller uses the back-propagation algorithms of neural network. The learning pattern acquisition was obtained using computer simulation, which is more exact than human driving. The simulation program was developed in order to verify the acquisition of the learning pattern, learning itself, and the adequacy of the design controller. A computer simulation of the vehicle (including vehicle dynamics and steering) was used to verify the steering performance of the vehicle controller using the neural network. Good results were obtained. Also, the real unmanned electrical vehicle using neural network controller verified good results.