FUNDAMENTAL SCALING AND MODELLING OF A FREE JET BURNER

摘要

This paper examines the scaling and modelling fundamentals of turbulent free jet burners under isothermal air and combustion conditions with acetylene as the fuel. The turbulent characteristics and structure of the flow are examined, and the effects of scale between different jet sizes investigated. Comparisons of isothermal and combusting turbulent, free jets at different scales and Reynolds numbers were made, using results taken with LDA measuring techniques. Each nozzle had a constant exit velocity of 17m/s and diameters of 10, 15 and 20mm. Measurements were concentrated in the near field region of flow close to the jet exit, to a distance of 40 nozzle diameters downstream of the exit. The basic aerodynamic characteristics for each jet are identified from the mean velocity and turbulence profiles determined from LDA measurements. Comparisons are made between mean velocities, turbulence, jet decay, time correlations and energy spectrums, and the effects of using constant velocity scaling investigated.