Electric Field Induced Changes of a Diffusion Flame and Heat Transfer near an Impinging Surface

Yu-Chien Chien,Derek Dunn-Rankin

doi:10.3390/en11051235

Abstract

This research investigates heat transfer phenomena on a plate used with impinging electric field flames; i.e., flames burning in the presence of an electric field. Electric field effects on flames have been investigated in different applications but not when the flames are impinging on nearby surfaces. Challenges to measurement methods when an electric field is applied in the system have limited the understanding of changes to the temperature distributions and species concentrations caused by the field. This study uses an infrared forward looking infrared (FLIR) camera with Schlieren visualization to examine the heat flux from flames over an impinging plate with different electric fields applied. In particular, we study the electric field effects on flames when those flames transfer heat to a nearby plate, and then how that transfer can be controlled using the electric field. The results show that electric fields affect substantially the heat flux distribution through the ion-driven wind, particularly when the plate location is just above the flame tip.

Highlights

This paper describes how an electric field controlled flame can change the temperature distribution over the plate on which the flame impinges
This study study investigates investigates the the temperature temperature and and heat heat transfer transfer of of an an impinging impinging plate plate with with the the effect effect from electric fields acting on a flame especially up to the limits of the plate quenching the flame andand up from electric fields acting on a flame especially up to the limits of the plate quenching the flame to electric field that canthat be applied
The plate shows a broadened upthe to maximum the maximum electric field can be without applied breakdown

Summary

Introduction

This paper describes how an electric field controlled flame can change the temperature distribution over the plate on which the flame impinges. Electric field actuated flames can occur because hydrocarbon flames naturally produce positive ions and negative charge carriers (generally electrons) in the reaction zone. H3 O+ is the most important ion for near stoichiometric mixture combustion, having a much higher concentration than other ions such as C2 H3 O+ , C3 H3 + and HCO+. Et al [1] found H3 O+ dominant in lean flames, and the strong consensus in the literature is that this ion is dominant for all flames actuated by negative fields. The fundamentals of chemi-ion production and the transport of these ions is well-documented in the literature so a complete repeat of this topic is not necessary [2]. A general finding in all cases is that the weak plasma reactions naturally occurring inside flames is not essential for any of the major heat release reaction pathways

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