Measurements of local velocities inside thin liquid films in horizontal two-phase flow

A new experimental facility based on Laser Doppler anemometry permits accurate local measurements in a horizontal pipe. Measurements of the axial velocity component in the liquid layer of the atomization/stratified flow regime are reported. The new information includes time-averaged local velocities, RMS values, probability density distributions, and power spectra. Elimination of velocity bias and calculation of velocity spectra is accomplished by a recently developed “signal reconstruction” algorithm. The data suggest that only in the vicinity of the solid surface (sublayer) does the liquid motion resemble the well-known behavior of single phase flow. Beyond that, the flow field is strongly influenced by the wavy gas/liquid interface and by the apparently intensive energy transfer from the very fast moving gas to the liquid layer.