The Effect of Mass Injection on Heat Transfer from a Partially Dissociated Gas Stream

An investigation of the effect of hydrogen and helium injection on local heat transfer to a porous surface from an oxygen-acetylene combustion gas stream is described. The free-stream temperature varied from 6200 to 5200 deg Rankine and the volumetric percentage of atomic hydrogen from 20 to 8. Flow in the boundary layer was found to be turbulent. Study of the results led to successful correlation of the ratio of the heat flux with injection to the heat flux without injection in terms of a dimensionless blowing parameter in which properties are evaluated at an average reference state. A method for predicting heat flux with injection was then developed. This is based on a temperature rather than an enthalpy potential because the latter resulted in anomalous values for the Stanton number under some of the test conditions.