http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : GOUTAM DUTTA (검색결과 5 건)
- 무료
- 기관 내 무료
- 유료
-
GOUTAM DUTTA,JAGDEEP B. DOSHI 한국원자력학회 2008 Nuclear Engineering and Technology Vol.40 No.6
The objective of the paper is to analyze the thermally induced density wave oscillations in water cooled boiling water reactors. A transient thermal hydraulic model is developed with a characteristics-based implicit finite-difference scheme to solve the nonlinear mass, momentum and energy conservation equations in a time-domain. A two-phase flow was simulated with a one-dimensional homogeneous equilibrium model. The model treats the boundary conditions naturally and takes into account the compressibility effect of the two-phase flow. The axial variation of the heat flux profile can also be handled with the model. Unlike the method of characteristics analysis, the present numerical model is computationally inexpensive in terms of time and works in a Eulerian coordinate system without the loss of accuracy. The model was validated against available benchmarks. The model was extended for the purpose of studying the flow-induced density wave oscillations in forced circulation and natural circulation boiling water reactors. Various parametric studies were undertaken to evaluate the model’s performance under different operating conditions. Marginal stability boundaries were drawn for type-I and type-II instabilities in a dimensionless parameter space. The significance of adiabatic riser sections in different boiling reactors was analyzed in detail. The effect of the axial heat flux profile was also investigated for different boiling reactors.
-
Dutta, Goutam,Doshi, Jagdeep B. Korean Nuclear Society 2008 Nuclear Engineering and Technology Vol.40 No.6
The objective of the paper is to analyze the thermally induced density wave oscillations in water cooled boiling water reactors. A transient thermal hydraulic model is developed with a characteristics-based implicit finite-difference scheme to solve the nonlinear mass, momentum and energy conservation equations in a time-domain. A two-phase flow was simulated with a one-dimensional homogeneous equilibrium model. The model treats the boundary conditions naturally and takes into account the compressibility effect of the two-phase flow. The axial variation of the heat flux profile can also be handled with the model. Unlike the method of characteristics analysis, the present numerical model is computationally inexpensive in terms of time and works in a Eulerian coordinate system without the loss of accuracy. The model was validated against available benchmarks. The model was extended for the purpose of studying the flow-induced density wave oscillations in forced circulation and natural circulation boiling water reactors. Various parametric studies were undertaken to evaluate the model's performance under different operating conditions. Marginal stability boundaries were drawn for type-I and type-II instabilities in a dimensionless parameter space. The significance of adiabatic riser sections in different boiling reactors was analyzed in detail. The effect of the axial heat flux profile was also investigated for different boiling reactors.
-
Neetesh Singh Raghuvanshi,Goutam Dutta,Manoj Kumar Panda 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.2
A mathematical model for supercritical water natural circulation loop (SCWNCL) is developed to study flow instabilities by linear stability analysis. The SCWNCL is a loop geometry, which is driven by natural circulation with supercritical water (SCW) as a coolant. A mathematical approach is developed to couple thermal-hydraulic (TH) model and neutron point kinetics (NPK) model. This nuclear coupled model is then used to perform a linear asymptotic stability analysis of the steady state of SCWNCL. A comprehensive numerical study of the linear asymptotic stability analysis is presented with particular emphasis on the effects of coupling. As a result of coupling, a transition from unstable to the stable region and vice-versa is observed for some governing parameter values, which is significantly different from the TH model. Furthermore, the stable operating zone’s are investigated by taking appropriate geometrical and operating conditions via stability analysis.
-
Gorti Janardhan,Kaushal Kishore,Goutam Mukhopadhyay,Krishna Dutta 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9
This study aims to investigate the influence of nugget diameter on tensile-shear and fatigue properties of the dissimilar resistancespot-welded joints of interstitial free and high strength niobium microalloyed steel sheets. The spot-weldings are doneat currents of 7 kA and 9 kA at welding time of 300 ms with electrode force of 2.6 kN. Fatigue tests are done at different loadamplitudes, considering the maximum tensile-shear load bearing capacity of the joints. The tests are interrupted before thefinal failure to understand the crack initiation and propagation paths. The study is supplemented by the microstructural anddetailed fractographic analyses. The results indicated that the fatigue strength of the spot-welds increased with a decrease innugget diameter. This could be attributed to the higher microhardness of heat affected zone (HAZ), presence of compressiveresidual stress and lower variation in thickness reduction on the IF steel side, welded at 7 kA. However, the tensile-shearload bearing capacity of the spot-welds increased with increase in the nugget diameter. The failure of the spot-welded jointunder static loading initiates from the HAZ/base metal interface of the IF steel side. Nevertheless, under cyclic loading crackinitiates from the notch root at the interface of two sheets lying in the HAZ of IF steel side. Fractographic investigationsindicate intergranular fracture features in combination with striations, secondary cracks on the IF steel side under cyclicloading. Fracture surfaces of the specimens failed under static loading shows however, shear dimples on the IF steel side.
-
Raghvendra Upadhyay,Santosh Kumar Rai,Goutam Dutta 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.3
The present study numerically investigates Density wave oscillations (DWOs), a dynamic instability and captures Heat transfer deterioration (HTD) phenomenon for a Supercritical water reactor (SCWR) of the U. S. reference design. A Thermal-hydraulic (TH) model is employed to solve the nonlinearly coupled mass, axial momentum and energy conservation equations in a time domain using characteristics based implicit finite difference scheme accounting for the compressible flow dynamics of supercritical water. The analysis of DWOs is carried out to obtain the marginal stability thresholds. Next, the steady as well as transient safety analyses are carried out to determine the occurrence of HTD, access its severity and identify the safe operating conditions. Finally, the common operating conditions are predicted where the U. S. SCWR will be stable as well as safe.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
