Final Report: Developing Liquid Protection Schemes for Fusion Energy Reactor First Walls
Over the last year, the Georgia Tech group has experimentally studied vertical turbulent sheets of water issuing downwards into atmospheric pressure air at Reynolds numbers Re = U{sub 0}{delta}/{nu} = 53,000 and 120,000 and Weber numbers We = {rho}U{sub o} {sup 2}{delta}/{sigma} = 2,900 and 18,000, respectively. Here, U{sub o} is the average jet speed, {delta} is the jet thickness (short dimension) at the nozzle exit ({delta} = 1 cm), and {nu}, {rho} and {sigma} are the kinematic viscosity and density of water and the surface tension at the air-water interface, respectively. These Re and We values are about 50% and 20% of the prototypical values for HYLIFE-II, respectively. In this report, the flow coordinate system is defined so that the origin is at the center of the nozzle exit, with the x-axis along the flow direction, the y-axis along the long dimension of the nozzle, and the z-axis along the short dimension of the nozzle (cf. Fig. 1). During the final year of this project, we have made three contributions in the area of thermal-hydraulics of thick liquid protection, namely: (1) Experimentally demonstrated that removing as little as 1% of the total mass flux using boundary-layer (BL) cutting can reduce the number density of the drops due to turbulent breakup of the liquid sheet below the maximum background density levels recommended for HYLIFE-II of 5 x 10{sup -19} m{sup 3}; (2) Shown that a well-designed flow conditioning section upstream of the nozzle can greatly reduce surface ripple, and that boundary-layer cutting can be used in conjunction with well-designed flow conditioning to further reduce surface ripple below the 0.07{delta} beam-to-jet standoff proposed for HYLIFE-II; and (3) Quantified how different flow conditioner designs affect the rms fluctuations of the streamwise (x) and transverse (z) velocity components in the nozzle itself (i.e., upstream of the nozzle exit) and affect surface ripple in the near-field of the flow, or x {le} 25{delta}. The rest of this section details these conclusions. In all cases, further details of this work can be found in the doctoral dissertation by Durbin.
- Research Organization:
- Georgia Institute of Technology, Atlanta, GA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- FG02-98ER54499
- OSTI ID:
- 878171
- Country of Publication:
- United States
- Language:
- English
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