A Study on Opposing Jets in Air Stream and their Flame : 1st Report, A Structure of Two Dimensional Opposing Jets in the State without Flames

Abstract

In order to obtain a knowledge about the fundamental characteristics of opposing jet flames, two dimensional opposing jets in air stream are treated experimentally in the state without flames. Results obtained are mainly summarized as follows. (1) By the value of velocity ratio λ, opposing jets are divided into two types as follows ; the nozzle attached type flow (N-type flow) for λ<1 and the recirculation type flow (R-type flow) for λ>1.65. And for 1<λ<1.65, the transition type flow can be recognized. Each type of flow is decided by the fact whether the stable recirculation eddy is formed or not in the region a little behind the outlet of nozzle. (2) The flow field is examined by drawing up the isobaric line diagram, the flow pattern and the diagram of constant concentration. And in R-type flow, it can be divided into the negative pressure region near the outlet of nozzle and the positive pressure region near the stagnation point. In each region, the concentration is made uniform and it is considered that such a type flow is useful for combustion. (3) Considering penetration distances, their experimental equations are obtained.