DC conduction liquid metal electromagnetic pump flow field distortion and its electromagnetic configuration compensation

A heat dissipation method using a DC-conduction electromagnetic pump (DC-EMP) to drive a low-melting-point gallium-based liquid metal as a cooling workpiece, which has significant prospects in the field of heat dissipation in chips. In order to weaken the magnetohydrodynamic (MHD) effect of liquid metals and its resulting flow field distortion, and to improve the performance of DC-EMP. The flow characteristics of liquid metal, current density field, magnetic induction strength and Lorentz force vector distribution in the flow channel were investigated, and the electromagnetic configuration was compensated by using an iron yoke and an insulation bars in order to increase the magnetic induction strength and the effective current in the DC-EMP region of action, thus weakening the MHD effect. The results show that the liquid metal near the side wall surface is accelerated by the MHD effect, the flow velocity in the main flow zone decreases, and the liquid metal in the flow channel undergoes serious flow field distortion after passing through the magnetic field zone. The induced current generated by the liquid metal cutting the magnetic susceptibility line forms an eddy current at the end of the action zone, which attenuates the effective current within the action zone, and at the same time, under the coupling of the eddy current and the end effect of electric and magnetic fields, it generates a Lorentz force resistance outside the action zone in the opposite direction of the flow velocity, which inhibits the liquid metal from entering and leaving the action zone, and thus reduces the performance of the DC-EMP. The tests show that the ∆P of the electromagnetic pump increases with the increase of the input current I_t, and the compensated ∆P is improved by 78.08% compared with the conventional structure when I_t = 50 A.