Experimental study of liquid metal convection driven by Seebeck effect under the influence of magnetic field

doi:10.7523/j.ucas.2024.032

Abstract

Abstract:

In a fusion reactor environment characterized by significant temperature variations and intense magnetic fields， the Seebeck effect interacts with the magnetic field， propelling the flow of liquid metal to remove impurities and heat generated during the fusion reaction. This paper conducts experiments on thermoelectric convection driven by the Seebeck effect in a horizontal magnetic field. GaInSn and constantan serve as the experimental working substances. An ultrasonic Doppler velocimetry system meticulously measures the convection velocity in a closed cavity. Three thermoelectric convection modes are identified. At lower magnetic fields， thermoelectric effects dominate the convective mode， allowing for an approximation as a two-dimensional flow. With increasing magnetic field strength， the convective mode transitions to a three-dimensional pattern exhibiting variable velocity fluctuations. Subsequently， it converts to an approximate two-dimensional flow， influenced by the magnetic damping effect under strong magnetic fields. The Lorentz force， resulting from the interaction between the thermoelectric effect and the magnetic field， can enhance heat transfer. However， under stronger magnetic fields， it has an inhibiting effect on heat transfer.

Key words: liquid metal, Seebeck effect, magnetohydrodynamic effects, thermoelectric convection

CLC Number:

TK124

Dengke ZHANG, Zenghui WANG. Experimental study of liquid metal convection driven by Seebeck effect under the influence of magnetic field[J]. Journal of University of Chinese Academy of Sciences, 2026, 43(2): 164-172.

Figures/Tables 10

Table 1 Nondimensional parameters and their ranges

参数名称	符号	定义	研究范围
磁雷诺数	$R e m$	$R e m = u 0 l η$	$R e m ≪ 1$
哈特曼数	$H a$	$H a = B l σ μ$	$0 < H a < 103$
雷诺数	$R e$	$R e = ρ u 0 l μ$	$0 < R e < 3 × 103$
塞贝克数	$T e$	$T e = ρ σ S B Δ T l 2 μ 2$	$0 < T e < 2 × 109$
格拉肖夫数	$G r$	$G r = β g Δ T l 3 v 2$	$0 < G r < 2 × 106$
特征速度	$U 0$	$U 0 = σ B Δ S Δ T ρ$	—

Table 1 Nondimensional parameters and their ranges

参数名称	符号	定义	研究范围
磁雷诺数	$R e m$	$R e m = u 0 l η$	$R e m ≪ 1$
哈特曼数	$H a$	$H a = B l σ μ$	$0 < H a < 103$
雷诺数	$R e$	$R e = ρ u 0 l μ$	$0 < R e < 3 × 103$
塞贝克数	$T e$	$T e = ρ σ S B Δ T l 2 μ 2$	$0 < T e < 2 × 109$
格拉肖夫数	$G r$	$G r = β g Δ T l 3 v 2$	$0 < G r < 2 × 106$
特征速度	$U 0$	$U 0 = σ B Δ S Δ T ρ$	—

Fig.1 TEMC experimental system and ultrasonic Doppler velocimetry system platform

Table 2 Physical properties of GaInSn and constantan

参数	工质 Ga68%In20%Sn12% (290 K)	康铜 (290 K) 型号 (6J40) Mn1%Ni39%Cu60%
熔点/℃	10.5	1 280
密度/(kg·m^-3)	6 360	8 900
动力黏度/(Pa·s)	2.4×10^-3	—
热导率/(W/(m·K))	16.5	—
电导率/(S·m^-1)	3.3×10⁶	2×10⁶
比热/(J/(kg·K))	365.8	—
塞贝克系数/(μV/K)	-0.55	-35
热膨胀系数	0.000 124	—

Fig.2 Spatiotemporal distribution of the flow velocity at the square cavity in a magnetic field-free environment （Ha=0，ΔT=1 415 K/m）

Fig.3 Spatiotemporal distribution of the flow velocity at the square cavity in a magnetic field environment （Ha=19， ΔT=1 415 K/m）

Fig.4 Spatiotemporal distribution of the flow velocity at the square cavity in a magnetic field environment （Ha=68，ΔT=1 415 K/m）

Fig.5 Spatiotemporal distribution of the flow velocity at the square cavity in a magnetic field environment （Ha=960，ΔT=1 415 K/m）

Fig.6 Distribution characteristics of Re and Ha2/Te of TEMC in a square cavity under different magnetic field strengths

Fig.7 Characterization of the distribution of Nu with Ha2/Te for TEMC in a closed cavity

Fig.8 Comparison of the fitted curves of Re versus Ha and Te with the literature on related thermoelectric magnetohydrodynamic experiments

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