The radial spread and axial decay of temperature in turbulent condensing jets

摘要

Radial and axial time-averaged temperature distributions in turbulent steam jets discharged into ambient air under unchoked/choked and saturated/superheated nozzle exit conditions have been measured with the aid of a fine thermocouple. Centreline decay and half-width spreading rates were calculated for these two-phase (liquid and vapour), two-fluid (air and water) jets and compared with data from the literature for non-condensing jets. Condensing jets exhibit higher spreading rates but much lower decay rates compared to non-condensing jets. A significant temperature increase due to condensation was observed. This increase in temperature became smaller with increased superheat and hence reduced condensation. Preliminary computational fluid dynamics (CFD) simulations were also performed using various simplifying assumptions.