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Title: An Experimental Reversed Heat Flux Investigation of the Helium-Cooled Modular Divertor with Multiple Jets

Abstract

The Georgia Institute of Technology group has performed studies to characterize the thermal hydraulics of a single “finger” module of the helium-cooled modular divertor with multiple jets (HEMJ) proposed for long-pulse magnetic fusion reactors in a helium (He) loop designed with maximum mass flow rate of 10 g/s. However, testing divertor modules at prototypical heat fluxes and temperatures remains an engineering challenge. A new larger helium loop with a maximum mass flow rate of 100 g/s, suitable for evaluating helium-cooled divertors with larger surface areas such as a nine-finger HEMJ module, is currently being constructed. This work presents an experimental validation of a numerical model exploring the applicability of the “reversed heat flux approach,” which cools (versus heats) the plasma-facing surface of the divertor module to evaluate the helium-side heat transfer coefficient (HTC). The approach is to be used for performance evaluation of single and multiple modules of HEMJ in existing and future large helium loops. A cooling facility for producing a jet of water with a maximum mass flow rate of 1.4 kg/s at a maximum pressure of 0.4 MPa and temperature of 295 K (Re = 2.2 × 10 5) is described. Numerical and experimental results are presentedmore » for the heat flux and average helium impingement surface temperature over a range of water flow rates (0.5 to 1.4 kg/s) for heat fluxes as high as 5 MW/m 2. The numerical model suggests that the HTC of the water impingement surface is comparable to or greater than that of the helium impingement surface. For given helium and water temperatures, the heat flux values are generally limited by conduction across the outer shell. These initial studies provide guidance on extending this approach to estimating the thermal-hydraulic performance of larger divertor module designs while reducing the challenges associated with studying such designs in the normal heating configuration at their extremely high prototypical temperatures and incident heat fluxes.« less

Authors:
ORCiD logo [1]; ORCiD logo [1];  [1]; ORCiD logo [1]
  1. Georgia Inst. of Technology, Atlanta, GA (United States). G. W. Woodruff School of Mechanical Engineering
Publication Date:
Research Org.:
Georgia Inst. of Technology, Atlanta, GA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24); National Science Foundation (NSF)
OSTI Identifier:
1593401
Grant/Contract Number:  
FG02-01ER54656; DGE-1650044
Resource Type:
Accepted Manuscript
Journal Name:
Fusion Science and Technology
Additional Journal Information:
Journal Volume: 75; Journal Issue: 8; Journal ID: ISSN 1536-1055
Publisher:
American Nuclear Society
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; helium-cooled divertor; reversed heat flux; impinging jet; thermal-hydraulics

Citation Formats

Musa, S. A., Lee, D. S., Abdel-Khalik, S. I., and Yoda, M. An Experimental Reversed Heat Flux Investigation of the Helium-Cooled Modular Divertor with Multiple Jets. United States: N. p., 2019. Web. doi:10.1080/15361055.2019.1643683.
Musa, S. A., Lee, D. S., Abdel-Khalik, S. I., & Yoda, M. An Experimental Reversed Heat Flux Investigation of the Helium-Cooled Modular Divertor with Multiple Jets. United States. doi:10.1080/15361055.2019.1643683.
Musa, S. A., Lee, D. S., Abdel-Khalik, S. I., and Yoda, M. Fri . "An Experimental Reversed Heat Flux Investigation of the Helium-Cooled Modular Divertor with Multiple Jets". United States. doi:10.1080/15361055.2019.1643683.
@article{osti_1593401,
title = {An Experimental Reversed Heat Flux Investigation of the Helium-Cooled Modular Divertor with Multiple Jets},
author = {Musa, S. A. and Lee, D. S. and Abdel-Khalik, S. I. and Yoda, M.},
abstractNote = {The Georgia Institute of Technology group has performed studies to characterize the thermal hydraulics of a single “finger” module of the helium-cooled modular divertor with multiple jets (HEMJ) proposed for long-pulse magnetic fusion reactors in a helium (He) loop designed with maximum mass flow rate of 10 g/s. However, testing divertor modules at prototypical heat fluxes and temperatures remains an engineering challenge. A new larger helium loop with a maximum mass flow rate of 100 g/s, suitable for evaluating helium-cooled divertors with larger surface areas such as a nine-finger HEMJ module, is currently being constructed. This work presents an experimental validation of a numerical model exploring the applicability of the “reversed heat flux approach,” which cools (versus heats) the plasma-facing surface of the divertor module to evaluate the helium-side heat transfer coefficient (HTC). The approach is to be used for performance evaluation of single and multiple modules of HEMJ in existing and future large helium loops. A cooling facility for producing a jet of water with a maximum mass flow rate of 1.4 kg/s at a maximum pressure of 0.4 MPa and temperature of 295 K (Re = 2.2 × 105) is described. Numerical and experimental results are presented for the heat flux and average helium impingement surface temperature over a range of water flow rates (0.5 to 1.4 kg/s) for heat fluxes as high as 5 MW/m2. The numerical model suggests that the HTC of the water impingement surface is comparable to or greater than that of the helium impingement surface. For given helium and water temperatures, the heat flux values are generally limited by conduction across the outer shell. These initial studies provide guidance on extending this approach to estimating the thermal-hydraulic performance of larger divertor module designs while reducing the challenges associated with studying such designs in the normal heating configuration at their extremely high prototypical temperatures and incident heat fluxes.},
doi = {10.1080/15361055.2019.1643683},
journal = {Fusion Science and Technology},
number = 8,
volume = 75,
place = {United States},
year = {2019},
month = {8}
}

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Works referenced in this record:

Thermal Hydraulics of Helium-Cooled Finger-Type Divertors at Higher Incident Heat Fluxes
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