The Influence of Electric Field Power Systems on Flame Behavior

摘要

This paper describes the effect of the electric field generated by two different high voltage power supplies on a coflowing jet flame. The paper is motivated by the increased availability of low-cost high-voltage power supplies and the question of whether their performance characteristics are suitable for flame-generated chemi-ion current measurements (nano/microamp) in sensitive environments. Economical designs, which may involve removing active current sinking components, can compromise a power supply's ability to respond on the millisecond time scales that have made the electric actuation of flames a unique approach to combustion sensing and control. The influence of several factors on the measured ion current, including rise time to a desired set point, precision and drift of the applied voltage, and voltage ripple, are important. Experiments are conducted using a small coflowing jet flame and two different power supplies; one supply is a high performance laboratory grade device and the other an inexpensive compact and lightweight unit. Methane is selected as the fuel source in order to reduce the potentially confounding influence of soot. Flame behavior is characterized optically and by the measured ion current. Optical measurements show the flame response and the response of the surrounding thermal field.