Hydrodynamic Characterization of Nickel Metal Foam, Part 2: Effects of Pore Structure and Permeability

Miwa, Shuichiro,Revankar, Shripad T. Springer-Verlag 2011 Transport in porous media Vol.89 No.3

Numerical simulation of bubble formation and condensation of steam air mixture injected in subcooled pool

Qu, Xiaohang,Revankar, Shripad T.,Tian, Maocheng Elsevier 2017 Nuclear engineering and design Vol.320 No.-

<P><B>Abstract</B></P> <P>Bubble formation and condensation of steam-air mixture vertically injected in a subcooled water pool was simulated, combining thermal phase change model into the two continuous phase free surface model of ANSYS CFX 17.1. Continuous surface force model was used to calculate surface tension force and the influence of non-condensable gas was accounted for by component transportation equation and assumption of interface temperature equal to saturation temperature at local partial steam pressure. The thermal phase change model includes an experimental correlation for liquid side sensible heat transfer. Based on available experiment data from literatures, singular pure steam bubble and steam-mixture bubble in a pool were first simulated to see the predictability of the proposed method and then, the same method was applied to the bubble formation, detachment and condensation process of injected steam air mixture from a nozzle. Bubble dimeter, water subcooling and non-condensable gas concentration studied range from 4.9mm to 50mm, 12K to 40K, and 0 to 31.5% respectively. The results of the computations indicate that the present method can predict very well the bubble formation and condensation both for pure steam case and with non-condensable gas.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bubble formation and condensation process injected from a nozzle is studied numerically. </LI> <LI> Euler-Euler two-fluid free surface model and species model from are coupled together. </LI> <LI> Influence of non-condensable gas is considered. </LI> <LI> Bubble shape variation histories are shown in comparison with experiments. </LI> </UL> </P>

Buoyant jet and two-phase jet-plume modeling for application to large water pools

Norman, Timothy L.,Revankar, Shripad T. Elsevier 2011 Nuclear engineering and design Vol.241 No.5

<P><B>Highlights</B></P><P>► A two-phase jet-plume model was developed to predict pool thermal response, pool surface temperature and consequently the pool cover gas pressure in enclosed spaces such as nuclear reactor wetwell. ► The jet-plume half-width, centerline velocity and temperature along the axis defining the plume's trajectory were solved as variables along the path. ► The pool surface temperature prediction is comparable to experimental data within 0.5°C.</P> <P><B>Abstract</B></P><P>Models of a single-phase liquid-into-liquid buoyant jet and a two-phase vapor-into-liquid turbulent jet-plume injected in horizontal orientation were developed for analyzing the dynamics of the mixing characteristics and thermal response for shallow submergence of the source in large pools. These models were developed from the Reynolds averaged Navier–Stokes equations in the cylindrical system for steady axisymmetric flow and incorporated the integral plume theory. The bases for the general assumptions such as self-similarity and use of Gaussian profiles to represent the velocity field across the effluent cross-section are examined. Subroutines were developed to reproduce the governing differential equations formulated from the continuity, momentum and conservation of buoyancy or energy equations which treats the jet-plume's half-width, velocity and temperature as variables and seek solutions of these variables along the jet-plume trajectory. Information on empirical closure relations obtained from experimental data such as the coefficient-of-entrainment, bubble slip velocity, momentum amplification factor, and plume spread-ratios for buoyancy and density-defect which are available for adiabatic cases were applied to the case of steam-into-water. Solutions were obtained without cross-flow in a linearly stratified ambient and then with cross-flow in a homogeneously mixed ambient for the single-phase formulation that represents a complete condensation scenario of a buoyant jet. The model was finally extended to the turbulent two-phase jet-plume case and the results were compared to available jet-plume pool condensation data. The analysis and results proved to be comparable to experimental data in predicting the pool surface temperature to within 0.5°C, however, temperature fluctuations along the jet-plume path were not adequately captured by the model since an oscillating input component was not incorporated in the model formulation; indeed the pool surface temperature proved to be of higher importance, which was adequately captured by the model.</P>

ECONOMIC VIABILITY TO BeO-UO_2 FUEL BURNUP EXTENSION

S. K. KIM,W. I. KO,H. D. KIM,정양헌,방성식,SHRIPAD T. REVANKAR 한국원자력학회 2011 Nuclear Engineering and Technology Vol.43 No.2

This paper presents the quantitative analysis results of research on the burnup effect on the nuclear fuel cycle cost ofBeO-UO_2 fuel. As a result of this analysis, if the burnup is 60 MWD/kg, which is the limit under South Korean regulations,the nuclear fuel cycle cost is 4.47 mills/kWh at 4.8wt% of Be content for the BeO-UO_2 fuel. It is, however, reduced to 3.70mills/kWh at 5.4wt% of Be content if the burnup is 75MWD/kg. Therefore, it seems very advantageous, in terms of theeconomic aspect, to develop BeO-UO_2 fuel, which does not have any technical problem with its safety and is a high burnup& long life cycle nuclear fuel.

Experimental investigation on the propagation characteristics of pressure oscillation in direct contact condensation with low mass flux steam jet

Qiu, Binbin,Yang, Qingchuan,Yan, Junjie,li, Gen,Revankar, Shripad T. Elsevier 2017 Experimental thermal and fluid science Vol.88 No.-

<P><B>Abstract</B></P> <P>The propagation characteristics of pressure oscillation in direct contact condensation with low mass flux steam jet have been investigated experimentally. Steam is injected into subcooled water at one atmosphere pressure with steam mass flux and water temperature range of 186–272kg/(m<SUP>2</SUP> s) and 293–343K. The pressure oscillation propagates in the form of wave with stable dominant frequency, however the wave intensity attenuates with the increasing distance from the oscillation source. The root mean square of pressure wave <I>p</I> <SUB>rms</SUB> attenuates rapidly with the increasing dimensionless radial distance from the nozzle exit. At about dimensionless radial distance <I>R</I> =100, the <I>p</I> <SUB>rms</SUB> is attenuated by about 90%. Although the dominant frequency of the pressure oscillation is constant during the propagation, after <I>R</I> =100, there will be not enough energy for the pressure oscillation to resonate with relevant equipment. A correlation equation to calculate the root mean square of pressure oscillation along the radial distance is given. The prediction errors are within ±30% compared with the experimental data.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The pressure oscillation propagates in the form of wave. </LI> <LI> In the propagation process, the frequency remains the same but the intensity attenuates. </LI> <LI> A correlation to calculate the <I>p</I> <SUB>rms</SUB> along the radial distance is given. </LI> <LI> At about R=100, the <I>p</I> <SUB>rms</SUB> is attenuated by about 90% and most of the energy is dissipated. </LI> </UL> </P>

ECONOMIC VIABILITY TO BeO-UO₂ FUEL BURNUP EXTENSION

Kim, S.K.,Ko, W.I.,Kim, H.D.,Chung, Yang-Hon,Bang, Sung-Sig,Revankar, Shripad T. Korean Nuclear Society 2011 Nuclear Engineering and Technology Vol.43 No.2

This paper presents the quantitative analysis results of research on the burnup effect on the nuclear fuel cycle cost of BeO-$UO_2$ fuel. As a result of this analysis, if the burnup is 60 MWD/kg, which is the limit under South Korean regulations, the nuclear fuel cycle cost is 4.47 mills/kWh at 4.8wt% of Be content for the BeO-$UO_2$ fuel. It is, however, reduced to 3.70 mills/kWh at 5.4wt% of Be content if the burnup is 75MWD/kg. Therefore, it seems very advantageous, in terms of the economic aspect, to develop BeO-$UO_2$ fuel, which does not have any technical problem with its safety and is a high burnup & long life cycle nuclear fuel.