Diffusion combustion of a hydrogen microjet effluxing into air flow from a sphere

Abstract

Experimental results on the diffusion combustion of a hydrogen microjet escaping from a sphere enveloped in an air flow are presented. Two limiting cases of the outflow of a burning hydrogen microjet are considered: when the jet is located at the main flow divergence point on the sphere and at the opposite point (at the aft end), with different separated flow structures are realized. Three characteristic levels of hydrogen microjet flow velocity were studied, enabling the arrangement of various burning jet patterns at zero freestream velocity. The changes in the jet topology and structure were demonstrated in experiments. Flow visualization was performed using a thermal imager. A comparison was made with results obtained using a shadowgraph method.