Dimensional analysis of critical heat flux in subcooled water flow under one-side heating conditions for fusion application

Boscary, J.; Araki, M.; Schlösser, J.; Akiba, Masato; Escourbiac, F.

doi:10.1016/s0920-3796(98)00387-1

Cited by 52 publications

(24 citation statements)

References 15 publications

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“…The CHF can be conservatively estimated based on empirical correlations and experiment databases [3]. For the CP with the mentioned mass flow and the nominal operation conditions: static pressure of 10 bar, pressure drop of 6 bar and a maximum water inlet-outlet temperature difference of 70 ºC, a CHF of 47 MW/m² is calculated with the Tong-75 correlation for smooth circular pipes with the adjustment proposed by Boscary [4] for oneside, peaked heat load conditions; through the analysis of the relevant dimensionless numbers with experimental data.…”

Section: Subcooled Boiling To Enhance Heat Transfermentioning

confidence: 99%

“…The solid-fluid coupled model cannot simulate the subcooled boiling, so a "workaround" has been used to include this effect by adding a multiplying term to the input HTC function. As soon as the wall overheating, the temperature difference between the wall and that of the saturated vapor at the local pressure 13 bar (~180 °C) goes over a custom threshold of 10 °C, the HTC function grows exponentially, mimicking the effects of subcooled boiling [4]: lower wall overheating (40 °C difference) and higher heat flux (factor three) due to formation of vapor ( Figure 4).…”

Section: Description Of the Modelling Schemementioning

confidence: 99%

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Reviewed design of the high heat flux panels for the AUG and W7-X neutral beam calorimeter

Orozco

Froeschle

Harder

et al. 2019

Fusion Engineering and Design

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Each of the neutral beam injectors in the experimental devices ASDEX Upgrade and Wendelstein 7-X can be equipped with up to four positive ion sources with an injected neutral beam power of 2.5 MW per source. For the conditioning of the system, a movable calorimeter can be placed in the path of the neutral beam to dump the heat load. The main heat load on the calorimeter is absorbed by a set of calorimeter panels (CP). Its design, originally from 1988, specified the lifetime of the CPs to 25000 heating cycles and ruled out any plastic deformation due to thermal cyclic loading. This was predicted with the tools available at the time but years of operation show that plastic deformation of the CPs already occurs at the very beginning of the calorimeter full power operation. After some years mechanical fatigue has led a few times to water leaks and consequently to NBI system shutdowns for repair. For this reason, careful inspection of the CPs is performed frequently and deformed CPs are exchanged for new ones. This paper presents the analysis of the causes that lead to the failure of the old CPs and proposes an optimized design for new CPs to be manufactured in the near future to substitute the old ones. The new design aims at minimizing mechanical fatigue from thermal cycling by reducing maximum surface temperature and thermo-mechanical stresses and improving material properties.

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Section: Subcooled Boiling To Enhance Heat Transfermentioning

confidence: 99%

Section: Description Of the Modelling Schemementioning

confidence: 99%

Reviewed design of the high heat flux panels for the AUG and W7-X neutral beam calorimeter

Orozco

Froeschle

Harder

et al. 2019

Fusion Engineering and Design

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“…The modifying factor f peak is included to modify the wall heat flux apparent on the cylindrical surface of the coolant channel from the incident heat flux on the flat PFC tiles. This value is expected to be between 1.3 -2 [21,22,23,24]. The value of T w is determined via the heat transfer coefficient of the segment, defined in Section 2.2.4.…”

Section: Heat Sink Temperaturementioning

confidence: 99%

Development of a 1D thermofluid code for divertor target plate modeling

Jackson

Nicholas

Ireland

2019

Fusion Engineering and Design

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The Oxford Divertor Thermo-Fluid Code (OxDTFC) is a numerical model to assess and compare the steady state thermo-fluid performance of the cooling systems present in the divertor target plate region of a fusion tokamak. Two water-cooled divertor target plate concepts have been used to demonstrate the model: an ITER-like monoblock system and the High Pressure Jet Cascade (HPJC) modular concept. Model validation was carried out by comparing results for the ITER-like monoblock system with experimental and numerical data in the literature. This comparison showed OxDTFC could accurately replicate divertor target plate thermo-fluid results across various coolant flow rates, incident heat fluxes, and geometric parameters. OxDTFC is used to compare the performance of the ITER-like monoblock and HPJC systems under equivalent thermal boundary conditions. This analysis shows the HPJC system has pumping power requirements of ∼65% and coolant flow rates of ∼50% less than a comparable ITER-like monoblock system.

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“…A swirl tape in the tube is assumed using the modified empirical correlations of HTC evaluated by Gambill et al [10]. The range of application is that T w (wall temperature) −T sat (saturation temperature) = 40°C-90°C, P = 0.5-1.6 MPa, T in = 30°C-80°C, wall heat flux (WHF) <60 MW/m 2 , and twist ratio = 2-4 [11]. The pressure drop in pipe is obtained as 25.4 kPa per 0.1 m. With regard to the critical heat flux (CHF), the insertion of swirl tape tubes has been considered under water inlet conditions (ṁ = 0.39 kg/s, P in = 0.7 MPa, and T in = 35°C).…”

Section: Thermal Analysis By Htc Empirical Correlationsmentioning

confidence: 99%

Conceptual Design Analysis of Tungsten Monoblock Components for KSTAR Divertor

Song

Kim

et al. 2016

IEEE Trans. Plasma Sci.

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Tungsten (W) monoblock that consists of W according to ITER specifications, oxygen-free high conductive copper (Cu-OFHC), and CuCrZr has been designed in preparation for KSTAR upgrade for steady-state long-pulse operation with 27.5-MW heating power. Finite-element analysis has been performed by ANSYS Workbench. The hydraulic thermomechanical analysis is performed to investigate the optimal design parameters and the expected fatigue lifetime under the operating conditions with 5.4-MW/m 2 incident heat flux at the divertor. For a single W monoblock, the optimization gives a W thickness of 5 mm, a side thickness of 2.5 mm, a thickness in the back part of 6 mm, and a Cu-OFHC interlayer thickness of 0.5 mm. For a mock-up consisting of five optimized W monoblocks, the thermal fatigue analysis is performed. As a result, the maximum value of equivalent total strain in the CuCrZr tube is found to be 0.266%, which corresponds to for a fatigue lifetime of 23 000 cycles.Index Terms-Fatigue lifetime, hydraulic thermomechanical analysis, incident heat flux, KSTAR upgrade, optimal design parameters, tungsten monoblock.

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Dimensional analysis of critical heat flux in subcooled water flow under one-side heating conditions for fusion application

Cited by 52 publications

References 15 publications

Reviewed design of the high heat flux panels for the AUG and W7-X neutral beam calorimeter

Reviewed design of the high heat flux panels for the AUG and W7-X neutral beam calorimeter

Development of a 1D thermofluid code for divertor target plate modeling

Conceptual Design Analysis of Tungsten Monoblock Components for KSTAR Divertor

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