• Energy Research

Further considerations are given to the use of an electromagnetic flux concentrator for arc plasma control in a rotary arc current interrupter. Such flux concentrators have been previously proposed for plasma fusion and other plasma applications. The possible extension of the proposed method for enhancing the interruption of direct currents with a rotary arc interrupter is discussed with the aid of theoretical modeling of the concentrator geometry and with its possible enhancement of ablation from the arc containing cylinders.

Experimental results on atmospheric-pressure arc plasma convolutes in air around a polytetrafluoroethylene cylindrical shroud containing a magnetic field ( B-field) producing coil are presented. In this paper, the B-field coil is energized by a current separate from that flowing through the arc, and a separate RLC circuit was connected across the arc gap. Thus the magnitude and time duration of the B-field are independent of the arc current and the high-frequency current oscillations produced by the parallel RLC circuit. Experimental results for the time variation of the current through and voltage across the arc plasma for these different conditions are presented, along with high-speed photographs of the oscillating current arc. The effects of varying the B-field upon plasma pulsations formed by the independent B-field and RLC current oscillations are discussed.

A new approach for the electromagnetic control and propulsion of a current carrying electric arc plasma ring is described. The essence of the approach is to form and manipulate the arc plasma outside rather than inside a magnetic field producing coil so that pulsed plasma thrusts can be produced in a choice of different directions. The interaction of the electric arc, formed in atmospheric pressure air, with such a magnetic field has been investigated. It has been shown that a stable azimuthal plasma ring can be rapidly produced by the simple process of separating two annular contacts. Pulsed plasma propulsion is obtained when the arc plasma and B-field sustaining current is reduced to zero whereby the constraining electromagnetic forces are removed and, as a consequence, the resulting plasma ring expands radially outwards. Several different measurement techniques have been deployed for investigating the behavior of the plasma ring. These include electrical probing, B-field probing and high-speed plus video photography. The results suggest that the plasma control and propulsion is governed by a combination of effects including ablation of the material around which the plasma ring is formed and self-pressurization related to the device geometry, as well as the electromagnetic forces. Preliminary results indicate that through the use of appropriate device geometries, the arc plasma may be propelled in axially opposite directions as well as radially.

This paper describes a novel technique for interrupting direct currents (D.C.) with an electromagnetically convoluted arc in air at atmospheric pressure. Investigations are reported on the effects of using a separate current for producing the arc convolving electromagnetic field (B-field) to that being interrupted and using a separate R, L, C circuit in parallel with the arc contacts. Experimental results are presented for the time variation of currents flowing through the arc gap, the B-field coil and the parallel R, L, C circuit, along with the voltage across the arc gap.

A scroll air motor, also known as a scroll expander, is a relatively new concept to pneumatic actuators. Its unique structure leads to its feature of high ability in energy conversion. In recent years, scroll air motors have been adopted by combined heat and power boilers, uninterrupted power supplies, and some other energy storage systems as a new mechatronic device for energy conversion. The paper aims to present the work in developing a complete mathematical model of the scroll air motor for analysis of scroll energy efficiency and the factors affecting energy efficiency. The work will be reported in two parts of the paper. The paper describes the derivation of spiral equations, chamber volume calculations, and the driving torque of the scroll air motor. The dynamic process modeling and energy efficiency analysis will be presented in Part II of the paper.

The concept of converting the kinetic energy of quadcopter propellers into electrical energy is considered in this contribution following the feasibility study of the propeller vibrations, theoretical energy conversion, and simulation techniques. Analysis of the propeller vibration performance is presented via graphical representation of calculated and simulated parameters, in order to demonstrate the possibility of recovering the harvested energy from the propeller vibrations of the quadcopter while the quadcopter is in operation. Consideration of using piezoelectric materials in such concept, converting the mechanical energy of the propeller into the electrical energy, is given. Photographic evidence of the propeller in operation is presented and discussed together with experimental results to validate the theoretical concept.