METHOD FOR DETERMINATION OF STABLE AND UNSTABLE OPERATION ZONES OF CYLINDRICAL LINEAR ELECTROMAGNETIC INDUCTION PUMPS Russian patent published in 2008 - IPC H02K44/06 

FIELD: electrical engineering; MHD equipment.

SUBSTANCE: method consists in determination of stable and unstable operation zones of cylindrical linear induction pumps with three-phase excitation winding having a flat-wave linear current characteristic. Coils of the excitation winding have a constant number of turns throughout the length of the inductor and create a traveling variable magnetic field within a cylindrical liquid metal channel operating at a magnetic Reynolds number R_m>l and having an approximate boundary between stable and unstable operation zones. These zones are determined by the point of intersection of two modified parameters: magnetohydrodynamic interaction αRN and magnetic Reynolds number αR_m. The point of intersection of said parameters is applied to the plane of a curve being deduced from experiments αRN=f(αR_m). Moreover, if said point is situated below the curve then the pump operates stably, and if it is above the curve then the pump operates unstably, wherein - magnetic Reynolds number, , R - magnetohydrodynamic interaction parameter, - average radius of pump channel, τ- pole pitch, s - slip, μ - liquid metal magnetic permeability, σ -liquid metal electric conductivity, ω=2πf - circular frequency, b -height of the liquid metal channel, δ' - equivalent height of the nonmagnetic gap, В_mΔ - magnetic field induction in the middle of the channel, γ - liquid metal density, v_s=2τf - synchronous velocity of the traveling magnetic field.

EFFECT: ability to choose a working point of the pump in the region of absence of low-frequency pulsations having higher efficiency and reliability.

8 dwg