Simultaneous velocity and concentration field measurements of pulsating and heated coaxial turbulent jets in square turbulent duct flow

Kurzfassung

Simultaneous velocity and concentration measurements of the mixing of a confined coaxial jet in air are performed in a small scale windtunnel at atmospheric pressure, constant mass flow rates and three modes of operation: isothermal steady jet injection (Re_d = 32000); pulsed isothermal injection (St=0.08) and steady injection at elevated jet temperatures of deltaT=50K and deltaT=100 K. Instantaneous measurements of mass fraction are implemented using planar laser induced fluorescence (PLIF) of the acetone seeded injected flow. Simultaneous two-component velocity measurements are performed using particle image velocimetry (PIV). The contribution provides details of the PLIF-PIV measurement setup, data evaluation and accuracy estimation. Stochastic error convergence over the number of samples is assessed within the turbulent shear layer for first and second moments of velocity and mass fraction. Results from all modes of operation are discussed on the basis of velocity, mass fraction, Reynolds shear stress and turbulent mass flux.