Fusion Engineering and Design 83 (2008) 1082–1086 Contents lists available at ScienceDirect Fusion Engineering and Design journal homepage: www.elsevier.com/locate/fusengdes Experimental study of MHD effects on turbulent flow of Flibe simulant fluid in circular pipe Junichi Takeuchi a,∗ , Shin-ichi Satake b , Neil B. Morley a , Tomoaki Kunugi c , Takehiko Yokomine d , Mohamed A. Abdou a a Mechanical and Aerospace Engineering Department, Univeristy of California, Los Angeles, 420 Westwood Plaza, 44-114 Engineering IV, Los Angeles, CA 90095, USA b Department of Applied Electronics, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan c Department of Nuclear Engineering, Kyoto University, Yoshida, Sakyo, Kyoto 606-8501, Japan d Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan article info Article history: Available online 5 November 2008 Keywords: MHD Flibe Turbulent pipe flow PIV abstract An investigation of MHD effects on a Flibe (Li 2 BeF 4 ) simulant fluid has been conducted under the U.S.–Japan JUPITER-II collaboration program using the “FLIHY” pipe flow facility at UCLA. The present paper reports experimental results on turbulent pipe flow of an aqueous potassium hydroxide solution under magnetic field using particle image velocimetry (PIV) technique. The modification of turbulence was investigated by comparison of the experimental results with a direct numerical simulation (DNS) data base. The PIV measurements at Re=11,300 were performed with variable Hartmann numbers, and the modification of the mean flow velocity as well as turbulence reduction was observed. A flat velocity profile in the pipe center and a steep velocity gradient in the near-wall region exhibit typical character- istics of wall-bounded MHD flows. The DNS was performed approximately the same conditions and the comparison of turbulence statistics between PIV and DNS shows good agreement for up to Ha = 10. © 2008 Elsevier B.V. All rights reserved. 1. Introduction The design of tritium breeding blankets and plasma facing com- ponents is an important area of R&D activities toward a viable commercial nuclear fusion reactor. In recent research, a molten salt coolant, Flibe (Li 2 BeF 4 ), has attracted attention. Moriyama et al. [1] surveyed various design concepts using Flibe and suggested its use in reactor designs where high temperature stability and low MHD pressure drop were special concerns. Among the design concepts utilizing Flibe are HYLIFE-II [2], the APEX thick/thin liquid walls [3], FFHR [4], and a solid first wall design based on advanced nano- composite ferritic steel [5]. Although Flibe has attractive features as coolant and tritium breeding material, there are some issues mak- ing Flibe-based blanket design challenging [5]. The main issues include (1) thermal conductivity of Flibe (1 W/mK) is low com- pared to other lithium-containing metal alloys, Pb–17Li (15 W/mK) and Li (50 W/mK), (2) kinematic viscosity of Flibe is high, espe- cially at temperatures close to the melting point (11.5 × 10 -6 m 2 /s at 500 ◦ C), and (3) the high melting point of Flibe requires structural material with temperature range over 650 ◦ C. ∗ Corresponding author. Tel.: +1 310 794 4452; fax: +1 310 825 2599. E-mail address: takeuchi@fusion.ucla.edu (J. Takeuchi). The limited operating temperature window of Flibe coolant requires good heat transfer from heated surface to the bulk flow. However, the high viscosity and low thermal conductivity put Flibe in the class of high Prandtl number fluids. In order to obtain suffi- ciently large heat transfer using high Prandtl number fluid coolant, strong turbulence is required. On the other hand, Wong et al. [5] suggested that the parameter Ha/Re would exceed the critical value of 0.008 given by Branover [6], especially in large channels, which indicated the suppression of turbulence might be significant. In this paper, the Reynolds number is defined as Re= U b D/, and the Hartmann number as Ha = BR  / where U b , D, , B, R,  and  are mean velocity, pipe diameter, kinematic viscos- ity, magnetic flux density, pipe radius, electrical conductivity and fluid density, respectively. Comparisons of typical non-dimensional parameters between the current experiments and the design pro- posed by Wong et al. [5] are shown in Table 1. The MHD effects on turbulent flows have been investigated extensively; however, most of the experimental efforts were con- ducted using liquid metals as working fluids [7,8]. Liquid metals are generally classified as low Prandtl number fluids, and the heat transfer characteristics of low Prandtl number fluids are conduc- tion dominant. However, the MHD effects on high Prandtl number, low conductivity fluids are yet to be understood. Thus it is impor- tant to investigate the effect of magnetic fields on the turbulent 0920-3796/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.fusengdes.2008.08.050