Cylindrical Inductor System with Internal Bifilary Solenoid. Analysis of Electromagnetic Characteristics

Abstract

A cylindrical inductor system with an internal coaxial solenoid, the winding of which is made in the form of a bifilar, is considered. The physical and mathematical model of the proposed system assumes the working conditions when the external inductor is turned off, its turns are made of metal with high electrical conductivity; sufficiently close to each other, so that their inner surface can be considered a continuous surface of the ideal conductor. The coils of the bifilar winding are made of metal tape and do not affect the occurring electromagnetic processes. A harmonic current flows in the bifilar.

Based on the calculated ratios for the strengths of the fields excited in the system, numerical estimates of the characteristics of the electromagnetic processes are obtained.

The case when the currents in each of the branches of the bifilar which directed in opposite directions is analyzed. Various cases of the transverse and longitudinal dimensions of the system are considered, as well as options for connecting one or two bifilar coils. It is shown that the integral magnetic flux in the internal cavity of the system under consideration, regardless of its design features, is zero and, accordingly, the inductance of the entire system as a whole is zero. The concentration of the magnetic flux in the system with a bifilar takes place in the cavity between its windings, which is explained by the positive superposition of the unidirectional induction vectors of the excited fields. Changes in the geometry and number of components allow varying the indices of the radial distributions of electro-magnetic fields in the inductor system considered. The obtained numerical estimates for the characteristics of magnetic fields excited in inductor system, real design first proposed by the authors, excited by directed in opposite directions currents in the windings of the bifilar, will be useful in choosing working design solutions for the corresponding elements of magnetic pulse metal processing equipment.

The proposed method of analysis will also allow appropriate experimental studies, as well as calculation and analysis of electromagnetic processes in inductor systems, where bifilar coils are placed on top of cylindrical solenoids, which is very interesting for the formation for new equipment magnetic-pulse processing of metal.