A Simple Method to Visualize a Transient Flow of Unburnt Gas in a Chamber

Abstract

Techniques of gas flow measurement in the field of combustion have greatly advanced since optical methods such as the laser Doppler velocimeter were introduced. Most of them, however, cannot map the velocity distribution over a plane of interest with a single observation. A fine wire which was set across a section of a combustion chamber was heated for a very short period of time during which a sheath of unbrunt gas attached to the wire was heated to give rise to schlieren to make it possible to trace the schlieren as well as that of the flame front until the heated gas was consumed by the flame. The electric circuitry and the characteristics of the system were investigated to evaluate the usefulness of this method. A 100 μm Ni-Cr wire was used to observer the transient flow around and in front of the jet in a divided combustion chamber. The flow in a cusp of the wedge shaped flame front in a simple rectangular chamber was observed as another example.