Measurements of the mixture fraction properties of plane buoyant turbulent adiabatic wall plumes (adiabatic wall plumes) are described, emphasizing conditions far from the source where self-preserving behavior is approximated. The experiments involved helium/air mixtures rising along a smooth, plane and vertical wall. Mean and fluctuating mixture fractions were measured using laser-induced iodine fluorescence. Self-preserving behavior was observed 92-155 source widths above the source, yielding smaller normalized plume widths and near-wall mean mixture fractions than earlier measurements. Self-preserving adiabatic wall plumes mix slower than comparable free line plumes (which have 58 percent larger normalized widths) because the wall prevents mixing on one side and inhibits large-scale turbulent motion. Measurements of probability density functions, temporal power spectra and temporal integral scales of mixture fraction fluctuations are also reported.
展开▼
