This document discusses a first principles approach to designing annular linear induction pumps (ALIP). It begins by describing how liquid metals can be used for heat transfer and conduction applications due to their high thermal conductivity and electrical properties. It then notes that the standard method for designing ALIP uses an electric circuit approach that does not accurately capture coupling between electromagnetics and fluid dynamics. The document concludes by stating it will discuss a first principles approach to ALIP design that leads to more accurate models while providing insight into magnetohydrodynamic instabilities.

1. First Approach to the Design of Annular Linear Induction
Pumps using First Principles
Juha E. Nieminen1,4
and Carlos O. Maidana1,2,3
1
MAIDANA RESEARCH, 2885 Sanford Ave SW #25601, Grandville, MI 49418, United States
2
Idaho State University, Department of Mechanical Engineering, Pocatello, ID 83209, United States
3
Chiang Mai University, Dept. of Mechanical Engineering, Chiang Mai 50200, Thailand
4
University of Southern California, Department of Astronautical Engineering, Los Angeles, CA 90089, United States
Contact person: carlos.omar.maidana@maidana-research.ch | +1 208 904-0401
Abstract. Liquid alloy systems have a high degree of thermal conductivity far superior to ordinary non-metallic liquids
and inherent high densities and electrical conductivities. This results in the use of these materials for specific heat
conducting and/or dissipation applications. Typical applications for liquid metals include heat transfer systems, and
thermal cooling and heating designs. Uniquely, they can be used to conduct heat and/or electricity between non-
metallic and metallic surfaces. The motion of liquid metals in strong magnetic fields generally induces electric
currents, which, while interacting with the magnetic field, produce electromagnetic forces. Electromagnetic pumps
and electromagnetic flow meters, exploit the fact that liquid metals are conducting fluids capable of carrying currents
source of electromagnetic fields useful for pumping and diagnostics.
The standard method used to design electromagnetic pumps of the annular linear induction type is the electric circuit
approach. The idea behind this method relies on the assumption that the flow is laminar (pressure and velocity
independent of time). Hence the electromagnetic and hydrodynamic phenomena can be separated. Then the theory of
linear induction machines and electric circuits can be used. This method is not very accurate and it doesn’t provide an
understanding of the phenomenology and instabilities involved. The latter is truth because the coupling between the
electromagnetics and thermo-fluid mechanical phenomena observed in liquid metal thermos-magnetic systems, and
the determination of its geometry and electrical configuration, gives rise to complex engineering
magnetohydrodynamics and numerical problems where the different physical phenomena involved cannot always be
decoupled and therefore a multi-physics simulation constitutes a priority. The use of first principles to design annular
linear induction pumps leads to a more accurate design process while the analysis of the coupled physical phenomena
leads to a better understanding of the magnetohydrodynamics, its instabilities and it also constitutes the base for the
development of techniques for optimization and active flow control.
A first approach to the design of annular linear induction pumps using first principles is discussed.
Keywords: EM pumps; liquid metal; MHD; multiphysics; ALIP.