Assessment of Modified RELAP5 MOD3.2 Against LBE Natural Circulation Test Loops

Motivated by the significant natural circulation capability of lead–bismuth eutectic (LBE)–cooled systems, the RELAP5 MOD3.2 code was modified for the analysis of LBE-cooled reactors and non-nuclear systems. The thermo-physical properties of LBE have been incorporated into the code without affecting the code’s original performance; new heat transfer correlations for liquid metal have been implemented. For the purpose of validating the modified code, experimental results of two different LBE natural circulation test loops were compared with the code simulation results. The first one was a natural circulation setup process test at a power of 22.5 kW performed at the Natural Circulation Experimental (NACIE) facility. The simulated inlet and outlet LBE temperatures across the heat source and mass flow rate of LBE agreed well with the test data. The second one was natural circulation conditions under five different power levels conducted at the Natural Circulation Capability Loop (NCCL) facility. The LBE temperature difference and mass flow rate under different power levels predicted by the code were consistent with the experimental data. Generally speaking, the modified code gives acceptable results, and the code could be applied for further LBE systems thermal-hydraulic analysis.

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Two-phase natural circulation loop behaviour at atmospheric and subatmospheric conditions

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/0954408918787401 ◽

2018 ◽

Vol 233 (4) ◽

pp. 687-700

Author(s):

S Venkata Sai Sudheer ◽

K Kiran Kumar ◽

Karthik Balasubramanian

Keyword(s):

Heat Flux ◽

Physical Properties ◽

Spatial Variation ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Natural Circulation ◽

Two Phase ◽

Natural Circulation Loop ◽

Thermo Physical Properties

This paper aims to present the steady-state behaviour of two-phase natural circulation loop at atmospheric and sub-atmospheric conditions. One-dimensional numerical approach is adopted to evaluate various system parameters, with special emphasis on spatial variation of thermo-physical properties and flashing. Homogeneous equilibrium model is applied for two-phase flows. An in-house code is developed in MATLAB to solve numerical model iteratively. It is observed that consideration of spatial variation of thermo-physical properties can precisely predict the loop behaviour. The evaluated results are validated with the open literature and reasonably good agreement is observed. The heater inlet temperature, inlet pressure and heat flux are found to have significant influence on spatial variation of pressure, temperature and enthalpy. As system pressure decreases from atmospheric to sub-atmospheric (1–0.8 atm), it is observed that the sub-atmospheric loop gives a higher mass flow rate compared to atmospheric loop at lower heat fluxes. However, as the heat flux increases in the sub-atmospheric loop, the mass flow rate is reduced due to increased drag force in the loop.

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Experimental Study on Heat Transfer of Supercritical Kerosene in a Vertical Upward Tube

Volume 4: Heat and Mass Transfer Under Extreme Conditions; Environmental Heat Transfer; Computational Heat Transfer; Visualization of Heat Transfer; Heat Transfer Education and Future Directions in Heat Transfer; Nuclear Energy ◽

10.1115/ht2013-17079 ◽

2013 ◽

Cited By ~ 1

Author(s):

Dan Huang ◽

Wei Li ◽

Wei Zhang ◽

Guo-Qiang Xu ◽

Zhi Tao

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Critical Temperature ◽

Physical Properties ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Supercritical Pressure ◽

Fluid Temperature ◽

Thermo Physical Properties

A research on the heat transfer performance of kerosene flowing in a vertical upward tube at supercritical pressure is presented. In the experiments, insights are offered on the effects of the factors such as mass flow rate, heat flux and pressure. It is found that increasing the mass flow rate could enhance the heat transfer performances, while increasing the working pressure will deteriorate the heat transfer. Besides, the effect of heat flux on heat transfer is complicated. Based on the analysis of experimental data, enhancement of heat transfer occurs when the inner wall temperature of tube is higher than pseudo-critical temperature while the bulk fluid temperature is lower than the pseudo-critical temperature. At the supercritical conditions, heat transfer is influenced by the significant changes in thermo-physical properties, thus accurate evaluations of the thermo-physical properties become the key for the supercritical heat transfer calculations. The extended corresponding-state principle could be used for evaluating the density and the transport properties of kerosene, including its viscosity and thermal conductivity, at different temperatures and pressures. In order to obtain the numerical values of the heat capacity, a Soave–Redlich–Kwong (SRK) equation of state is used. The correlation for predicting heat transfer in kerosene at supercritical pressure is established, the calculation results from this correlation are in good agreement with the experimental results.

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CFD Simulation of Gas Distributor with Two Chambers

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.989-994.2264 ◽

2014 ◽

Vol 989-994 ◽

pp. 2264-2267

Author(s):

Dong Fang Zhao ◽

Feng Guo Liu

Keyword(s):

Natural Gas ◽

Mass Flow Rate ◽

Turbulence Model ◽

Mass Flow ◽

Flow Rate ◽

Cfd Simulation ◽

Second Order ◽

Gas Distributor ◽

New Type ◽

Simulation Results

This paper investigated a new type of gas distributor with two chambers by CFD software. The distributor has a natural gas inlet and nine nozzle outlets. For the investigation of this project, the mass flow rate of the distributor was analyzed in this paper to provide a way to optimize the structure of distributor. The N-S equations approached with the RNG k-ε turbulence model and the discretization were employed second order upwind. The simulation results will provide a number of useful suggestions and references for the further design.

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Study on Factors Affecting CHF Based on Factorial Analysis in Narrow Rectangular Channel Under Natural Circulation

Volume 9: Student Paper Competition ◽

10.1115/icone26-81863 ◽

2018 ◽

Author(s):

Li Zichao ◽

Zhou Tao ◽

Shi Shun ◽

Amir Haider ◽

Li Bing ◽

...

Keyword(s):

Mass Flow Rate ◽

Influencing Factors ◽

Mass Flow ◽

Flow Rate ◽

Natural Circulation ◽

Rectangular Channel ◽

Factorial Analysis ◽

Contribution Rate ◽

Factors Affecting ◽

System Pressure

Research on influencing factors of CHF in narrow rectangular channel under natural circulation is of great significance to the safety of reactors. Taking the narrow rectangular experimental device as the research object, influencing factors of CHF in narrow rectangular channel were experimentally studied under natural circulation. With factorial analysis, effects of different factors and their interactions on CHF were analyzed. It is found that the contribution rate of mass flow rate is the largest, followed by the effect of outlet dryness, followed by the effect of system pressure. Their interactions between different factors have little effects on CHF in narrow rectangular channel under natural circulation.

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Estimation of Leakage Mass Flow Rate through Labyrinth Seal Using CFD Techniques

International Journal of Science and Engineering Invention ◽

10.23958/ijsei/vol03-i02/02 ◽

2017 ◽

Vol 3 (02) ◽

Author(s):

M Neeharika ◽

Prabhat Kumar Hensh

Keyword(s):

Numerical Simulation ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Flow Behavior ◽

Labyrinth Seal ◽

Empirical Correlation ◽

Radial Clearance ◽

Leakage Flow ◽

Simulation Results

Seal design is an essential part for turbo machinery. Seal consisting of fins is placed in a gap between stationary and rotating component to minimize the leakage flow. Seal leakage flow has been considered as an inevitable loss factor that highly affects the efficiency of any machine. During operation of the equipment, thermal expansion/contraction of components take place, which causes variation of the gap between stationary and rotating component. Importance of the study is to understand the flow behavior due to variation of the gap. The variation of gap leads to change of radial clearance between fin to metal component and subsequent change of flow pattern. The main focus of the paper is to estimate the leakage flow through a labyrinth seal placed between rotor and casing of a typical steam turbine. Numerical techniques using 3D CFD tool are used for this purpose. Three different seal configurations are proposed in the study. The variables of the three seal configurations are radial clearance, number of fins in the flow passage and pressure drop across the seal passages. As an alternative methodology, an empirical correlation is formulated based on numerical simulation results for one set of radial clearance to estimate mass flow rate through the seal. In order to validate the formulated correlation, mass flow rate is determined for another set of radial clearance and compared with numerical simulation results. It is observed that flow rate estimated from 3D CFD study is around 20% lower compared to empirical correlation.

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Modelling of a Single Passage Air PV/T Solar Collector: Experimental and Simulation Design

Processes ◽

10.3390/pr8070763 ◽

2020 ◽

Vol 8 (7) ◽

pp. 763

Author(s):

Noran Nur Wahida Khalili ◽

Mahmod Othman ◽

Mohd Nazari Abu Bakar ◽

Lazim Abdullah

Keyword(s):

Error Analysis ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Solar Collector ◽

Total Efficiency ◽

Research Attention ◽

Air Mass ◽

One Dimensional ◽

Simulation Results

The hybrid photovoltaic/thermal solar collector has attracted research attention for more than five decades. Its capability to produce thermal energy simultaneously with electrical energy is considered attractive since it provides higher total efficiency than stand-alone photovoltaic or thermal systems separately. This paper describes theoretical and experimental studies of a finned single pass air-type photovoltaic/thermal (PV/T) solar collector. The performance of the system is calculated based on one dimensional (1D) steady-state analysis using one dimensional energy balance equations, where simulation was carried out using MATLAB. Experiments were carried out to observe the performance of the solar collector under changes in air mass flow rate. Experimental values on photovoltaic panel temperature and air temperature on both air inlet and outlet, together with the ambient temperature and solar radiation were measured. The simulation results were validated against the results obtained from experiments using the error analysis method, Root Mean Square Error. At a solar irradiance level of 800 to 900 W/m2, the thermal efficiency increases to 20.32% while the electrical efficiency increases to 12.01% when the air mass flow rate increases from 0.00015 kg/s to 0.01 kg/s. The error analysis shows that both experimental and simulation results are in good agreement.

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Detailed Evaluation of the Natural Circulation Mass Flow Rate of Water Propelled by Using an Air Injection

Journal of Nuclear Science and Technology ◽

10.1080/18811248.2008.9711432 ◽

2008 ◽

Vol 45 (3) ◽

pp. 238-243 ◽

Cited By ~ 2

Author(s):

Rae-Joon PARK ◽

Kwang-Soon HA ◽

Jae-Cheol KIM ◽

Seong-Wan HONG ◽

Sang-Baik KIM

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Natural Circulation ◽

Air Injection ◽

Detailed Evaluation

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Research on Natural Circulation Flow Characteristics of Floating Nuclear Power Plant in Heaving Motion

Volume 5: Advanced and Next Generation Reactors, Fusion Technology; Codes, Standards, Conformity Assessment, Licensing, and Regulatory Issues ◽

10.1115/icone25-66240 ◽

2017 ◽

Author(s):

Li Ren ◽

Peng Minjun ◽

Xia Genglei ◽

Zhao Yanan

Keyword(s):

Power Plant ◽

Nuclear Power Plant ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Nuclear Power ◽

Natural Circulation ◽

Flow Characteristics ◽

Circulation Flow ◽

Drift Flux Model

The FNPP (Floating Nuclear Power Plant) expanded the application field of Integrated Pressurized Water Reactor (IPWR) in the movable marine platform, it is necessary to study the natural circulation flow characteristics in heaving motion on the ocean. From the characteristics of FNPP, by means of THEATRe code which was based on the two-phase drift flux model and was modified by adding module calculating the effect of heaving motion, the simulation model in heaving motion was built. Using the models developed, the natural circulation operating characteristics of natural circulation in heaving motion and the transitions between forced circulation and natural circulation are analyzed. In the case of amplitude limited, the periods of mass flow rate are equal to periods of heaving motion. The oscillation amplitude of mass flow rate increases with the heaving amplitude increase. In the case of period limited, the natural circulation flow rate oscillating amplitude increases with the heaving period increases. The result obtained are not only evaluating FNPP design behavior properly but also pointing out the direction to further optimum design to ensure FNPP operating safety in heaving motion.

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Steady-State Energetic and Exergetic Performances of Single-Phase Natural Circulation Loop With Hybrid Nanofluids

Journal of Heat Transfer ◽

10.1115/1.4043819 ◽

2019 ◽

Vol 141 (8) ◽

Cited By ~ 13

Author(s):

Mayaram Sahu ◽

Jahar Sarkar

Keyword(s):

Steady State ◽

Mass Flow Rate ◽

Entropy Generation ◽

Mass Flow ◽

Flow Rate ◽

Natural Circulation ◽

Circulation Loop ◽

Hybrid Nanofluid ◽

Natural Circulation Loop ◽

Hybrid Nanofluids

Energy and exergy performances of natural circulation loop (NCL) with various water-based hybrid nanofluids (Al2O3 + TiO2, Al2O3 + CNT, Al2O3 + Ag, Al2O3 + Cu, Al2O3 + CuO, Al2O3 + graphene) with 1% volumetric concentration are compared in this study. New thermophysical property models have been proposed for hybrid nanofluids with different particle shapes and mixture ratio. Effects of power input, loop diameter, loop height, loop inclination and heater/cooler inclination on steady-state mass flow rate, effectiveness, and entropy generation are discussed as well. Results show that both the steady-state mass flow rate and energy–exergy performance are enhanced by using the hybrid nanofluids, except Al2O3 + graphene, which shows the performance decrement within the studied power range. Al2O3 + Ag hybrid nanofluid shows highest enhancement in mass flow rate of 4.8% compared to water. The shape of nanoparticle has shown a significant effect on steady-state performance; hybrid nanofluid having cylindrical and platelet shape nanoparticles yields lower mass flow rate than that of spherical shape. Mass flow rate increases with the increasing loop diameter and height, whereas decreases with the increasing loop and heater/cooler inclinations. Both effectiveness and entropy generation increase with the decreasing loop diameter and height, whereas increasing the loop and heater/cooler inclinations. This study reveals that the particle shape has a significant effect on the performance of hybrid nanofluids in NCL, and the use of hybrid nanofluid is more effective for higher power.

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