• International Journal of Fluid Machinery and Systems
• /
• 제3권1호
• /
• pp.20-28
• /
• 2010

This paper deals with the Design and Analysis of a Controlled Diffusion Aerofoil (CDA) Blade Section for an Axial Compressor Stator and Effect of incidence angle and Mach No. on Performance of CDA. CD blade section has been designed at Axial Flow Compressor Research Lab, Propulsion Division of National Aerospace Laboratories (NAL), Bangalore, as per geometric procedure specified in the U.S. patent (4). The CFD analysis has been performed by a 2-D Euler code (Denton's code), which gives surface Mach No. distribution on the profiles. Boundary layer computations were performed by a 2-D boundary layer code (NALSOF0801) available in the SOFFTS library of NAL. The effect of variation of Mach no. was performed using fluent. The surface Mach no. distribution on the CD profile clearly indicates lower peak Mach no. than MCA profile. Further, boundary layer parameters on CD aerofoil at respective incidences have lower values than corresponding MCA blade profile. Total pressure loss on CD aerofoil for the same incidence range is lower than MCA blade profile.

• Earthquakes and Structures
• /
• 제9권2호
• /
• pp.391-413
• /
• 2015

Damage of torsionally coupled buildings situated on soil sites has been reported in literature, however no site-specific studies are available for torsionally coupled buildings having site characteristics as a parameter. Effect of torsion is being accounted in seismic codes by the provision of design eccentricity where the dynamic to static eccentricity ratio is a parameter. In this paper, a methodology to determine dynamic to static eccentricity ratio of torsionally coupled buildings has been demonstrated for Delhi region for two torsionally coupled buildings on three soil sites. The variations of average and standard deviations of frame shears for stiff and flexible edges are studied for four eccentricity ratios for the two buildings for the three sites. From the limited studies made, it is observed that the dynamic to static eccentricity ratios observed for site-specific earthquakes are different from Indian seismic code specified value, hence a proposal is made to include a comment in Indian seismic code. Methodology proposed in this paper can be adopted for any region, for the estimation of dynamic to static eccentricity ratio for site specific earthquake.

• Nuclear Engineering and Technology
• /
• 제53권9호
• /
• pp.2830-2838
• /
• 2021

This work deals with the assessment of the burnup capabilities of the Serpent Monte Carlo code to predict spent nuclear fuel (SNF) isotopic concentrations for low-enriched uranium (LEU) fuel at different burnup levels up to 47 MWd/kgU. The irradiation of six UO₂ experimental samples in three different VVER-1000 reactor units has been simulated and the predicted concentrations of actinides up to ²⁴⁴Cm have been compared with the corresponding measured values. The results show a global good agreement between calculated and experimental concentrations, in several cases within the margins of the nuclear data uncertainties and in a few cases even within the reported experimental uncertainties. The differences in the performances of the JEFF3.1.1, ENDF/B-VII.1 and ENDF/B-VIII.0 nuclear data libraries (NDLs) have also been assessed and the use of the newly released ENDF/B-VIII.0 library has shown an increased accuracy in the prediction of the C/E's for some of the actinides considered, particularly for the plutonium isotopes. This work represents a step forward towards the validation of advanced simulation tools against post irradiation experimental data and the obtained results provide an evidence of the capabilities of the Serpent Monte-Carlo code with the associated modern NDLs to accurately compute SNF nuclide inventory concentrations for VVER-1000 type reactors.

• Structural Engineering and Mechanics
• /
• 제69권3호
• /
• pp.293-306
• /
• 2019

In current seismic design codes, various elastic design acceleration spectra are defined considering different seismological and soil characteristics and are widely used tool for calculation of seismic loads acting on structures. Response spectrum analyses directly use the elastic design acceleration spectra whereas time history analyses use acceleration records of earthquakes whose acceleration spectra fit the design spectra of seismic codes. Due to the fact that obtaining coherent structural response quantities with the seismic design code considerations is a desired circumstance in dynamic analyses, the response spectra of earthquake records used in time history analyses had better fit to the design acceleration spectra of seismic codes. This paper evaluates structural response distributions of multi-story reinforced concrete frames obtained from nonlinear time history analyses which are performed by using the scaled earthquake records compatible with various elastic design spectra. Time domain scaling procedure is used while processing the response spectrum of real accelerograms to fit the design acceleration spectra. The elastic acceleration design spectra of Turkish Seismic Design Code 2007, Uniform Building Code 1997 and Eurocode 8 are considered as target spectra in the scaling procedure. Soil classes in different seismic codes are appropriately matched up with each other according to $V_{S30}$ values. The maximum roof displacements and the total base shears of considered frame structures are determined from nonlinear time history analyses using the scaled earthquake records and the results are presented by graphs and tables. Coherent structural response quantities reflecting the influence of elastic design spectra of various seismic codes are obtained.

• Nuclear Engineering and Technology
• /
• 제56권6호
• /
• pp.2274-2281
• /
• 2024

RESRAD-ONSITE v7.2 code is used to assess the radiation effects on a farmer resident located in a hypothetical contaminated site planned for the first nuclear power plant project in Vietnam, namely Ninh Thuan 1, after decommissioning. Derived concentration guideline levels are preliminarily calculated for 17 radionuclides that are assumed to remain on a contaminated surface soil with an initial concentration of 1 pCi/g in the protected area of NPP site. For a reliable estimation, the site-specific conditions regarding the geological, hydrological, climate, and occupancy data gathered from the Feasibility Study Report (FSR) and relevant literatures for the Ninh Thuan 1 NPP site is employed as input parameters. The calculation results indicate that the peak of total exposure dose is estimated to be ca. 0.191 mSv/yr at the time of decommissioning, and then decrease over time. Furthermore, the protected site is assessed to be released at ca. 6.71 years after decommissioning under the regulation on radiation protection in Vietnam. Through this study, a radiation exposure model for residents living near the Ninh Thuan 1 NPP is preliminarily established by using the RESRAD-ONSITE code, which are expected to be useful for future implementation of the Ninh Thuan 1 NPP project in Vietnam.

• Radiation Oncology Journal
• /
• 제13권3호
• /
• pp.285-289
• /
• 1995

목적 : 6 MeV의 전자선에 대하여 Monte-Carlo기법을 이용한 모의계산(simulation)과 측정을 함으로써 측정값과 계산값을 서로 비교하고, 이러한 모의계산이 측정을 대신할 수 있을 만큼의 정확도가 있는지를 확인하고자 하였다. 방법 : 선형가속기에서 출력되는 전자선의 심부량 백분율(percent depth dose)을 물팬톰에서 반도체 검출기를 이용하여 조사야 $50{\times}50,\;100{\times}100,\;150{\times}150,\;200{\times}200\;mm^2$에 대하여 측정하였다. 전자선에 대한 선량을 결정하기 위한 모의계산은 EGS4 프로그램을 사용하였다. 결과 : 측정값과 계산값은 유사한 형태로 나타났는데 $100{\times}100\;mm^2$ 조사야 에서 선축상최대선량은 측정값과 계산값이 각각 14mm 와 15mm, 표면선량율은 각각 $76.94\%$ 와 $65.52\%$였다. 모의계산에서 표면선량율의 조사야에 따른 변화는 $64.43\%-66.99\%$이고 선축상최대선량은 15mm-18mm 였다. 결론 : 모의계산을 한 결과, 계산값이 측정값과 비교적 잘 일치한다는 것을 알았다. 표면선량율의 차이만을 제거하고 결과를 살펴보면 선축상 최대치등 방사선 치료에 주로 이용되는 부츤의 선량율에서는 모의계산이 측정을 대신할 수 있을 만큼의 정확도가 있다는 것을 확인하였다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 추계학술대회
• /
• pp.1629-1633
• /
• 2004

Liquid is commonly introduced as transversal jets in venturi scrubber which is one of the gas cleaning equipments. The jet dynamics such as penetration and breakup is of fundamental importance to the dust-collection efficiency. We have developed a model that can numerically simulate the breakup of the liquid jet in crossflow. This simulation consists of models on liquid column, jet surface breakup, column fracture and secondary droplet breakup. These models have been embedded in the KIVA3-V code. We have calculated such parameters as the jet penetration, jet trajectory, droplet size, velocity field and the volume flux distribution. The results are compared with the experimental data in this paper.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
• /
• pp.77-82
• /
• 1997

The CANDU-6 transition core refuelled from 37-element fuel to CANFLEX-NU fuel has been evaluated by an 100full power day time-dependent fuel-management simulation to find the core compatibility with the CANFLEX fuel loading. The simulation calculations for the transition core were carried out with the RFSP code, provided by the cell averaged fuel properties obtained from the POWDERPUFS-V code. The simulation results were compared with those of the current 37-element fuel loading only. The results show that the CANFLEX-NU fuel bundles will be compatible with the CANDU-6 reactor because the core physics characteristics of CANFLEX-NU fuel are very similar to those of the 37-element fuel bundle.

• Journal of Electrical Engineering and Technology
• /
• 제10권5호
• /
• pp.2077-2082
• /
• 2015

Based on Deutsch assumption, a calculation method on the electric field over the ground surface under HVDC transmission lines in the wind is proposed. Analyzing the wind effects on the electric field and the space charge density the existing method based on Deutsch assumption is improved through adding the wind speed to the ion flow field equations. The programming details are illustrated. The calculation results at zero wind speed are compared with available data to validate the code program. Then the ionized fields which resulted from corona of ±800kV HVDC lines are analyzed. Both the electric field and the current density on the ground level are computed under different wind direction and speed. The computation results are in good agreement with measurements. The presented method and code program can be used to rapidly predict and evaluate the wind effects in HVDC transmission engineering.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2007년도 춘계종합학술대회
• /
• pp.510-513
• /
• 2007

가변길이 부호는 많은 이미지 및 영상 표준에서 폭넓게 사용되는 기법이다. 특히 국제 표준인 JVT와 중국 A/V 표준인 AVS는 엔트로피 코딩을 수행하기 위해 Exp-Golomb 코드에 기반한 UVLC(Universal Variable Length Code)를 채용하고 있다. 본 논문에서는 H.264/AVC의 엔트로피 코딩에서 사용되는 Exp-Golomb CODEC의 하드웨어 구현에 대해 연구하였다. 식의 간략화로 구현하기 어려운 log함수와 거듭제곱 연산을 하지 않으며, 첫 번째 1 검출기와 누산기 제어에 의한 배럴 쉬프터를 통하여 별도의 시간 지연 없이 부호화 및 복호화가 되도록 설계하였다. Xilinx ISE툴을 사용하여 합성하고, 보드 수준에서 PCI인터페이스를 사용하여 검증하였다. 본 논문에서 설계된 Exp-Glomb CODEC은 H.264/AVC 및 AVS와 같은 분야에서 응용이 가능할 것으로 예견된다.