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

In this work, steady air injection upstream of the blade leading edge was used in a transonic axial flow compressor, NASA rotor 37. The injectors were placed at 27 % upstream of the axial chord length at blade tip, the injection mass flow rate is 3% of the chock mass flow rate, and 3 yaw angles were used, respectively -20°, -30°, and -40°. Negative yaw angles were measured relative to the compressor face in opposite direction of rotational speeds. To reveal the mechanism, steady numerical simulations were performed using FINE/TURBO software package. The results show that the stall mass flow can be decreased about 2.5 %, and an increase in the total pressure ratio up to 0.5%.

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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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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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Mass flow rate effect on a rotating detonation combustor with an axial air injection

Shock Waves ◽

10.1007/s00193-020-00984-7 ◽

2021 ◽

Author(s):

T. Sato ◽

F. Chacon ◽

M. Gamba ◽

V. Raman

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Rate Effect ◽

Air Injection ◽

Rotating Detonation ◽

Flow Rate Effect

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

Frontiers in Energy Research ◽

10.3389/fenrg.2021.674353 ◽

2021 ◽

Vol 9 ◽

Author(s):

Yufeng Lv ◽

Xingmin Liu ◽

Weihan Li ◽

Chunqiu Guo ◽

Zhiwei Zhou

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Natural Circulation ◽

Hydraulic Analysis ◽

Original Performance ◽

Nuclear Systems ◽

Simulation Results ◽

Thermal Hydraulic Analysis ◽

Thermo Physical Properties

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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Optimization of the Efficiency of Stall Control Using Air Injection for Centrifugal Compressors—Additional Findings

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4039820 ◽

2018 ◽

Vol 140 (12) ◽

Cited By ~ 1

Author(s):

Taher Halawa

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Gas Turbines ◽

Stable Condition ◽

Tangential Direction ◽

Air Injection ◽

Centrifugal Compressors ◽

Injection Angle ◽

Stall Control

This study presents additional important findings to the results of the research paper; “Optimization of the efficiency of stall control using air injection for centrifugal compressors” published in the Journal of Engineering for Gas Turbines and Power in 2015 (Halawa, T., Gadala, M. S., Alqaradawi, M., and Badr, O., 2015, “Optimization of the Efficiency of Stall Control Using Air Injection for Centrifugal Compressors,” ASME J. Eng. Gas Turbines Power, 137(7), p. 072604). The aim of this study is to make a fine determination of the injection angle, which provides the best stable condition when the compressor operates close to stall condition. A relatively narrower range of injection angles with smaller intervals was selected comparing to the results of the referred published paper, which clarified that the best injection angle is 30 deg. External air was injected close to the diffuser entrance at the shroud surface. Injection was applied with mass flow rate equals 1.5% of the design compressor inlet mass flow rate with injection angles ranged from 16 deg to 34 deg measured from the tangential direction at the vaneless region. It was found that both of injection angles of 28 deg and 30 deg achieved the best results in terms of compressor stabilization but each one of them has a specific advantage comparing to the other one. Using injection angle of 28 deg provided the lowest kinetic energy losses while the best orientation of the fluid through diffuser resulted when using an injection angle of 30 deg.

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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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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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