Wind tunnel simulation of ammonia gas release transport processes

摘要

This work reports on experimental data and generalized correlations, which display the modification of a scalar field by the presence of obstacles. The data were obtained by means of a triple hot-wire probe in a wind tunnel. The global picture of the flow was visualized and recorded by a high-speed video system. The flow studied was a buoyant jet in a cross wind. This flow simulates an accidental ammonia release from a pressurized containment. The obstacle is found to enhance scalar turbulent dispersion and mixing. The simulated ammonia plume exhibits similar dynamic behavior with and without the obstacle, obtaining a self-similar state at distances downwind predicted by dimensional arguments. The scalar probability density functions display deviations from Gaussian distribution, depending upon their distance from the jet center. The data support a gradient transport hypothesis modeling. Recirculation patterns contributing to the entrainment processes were identified in the near wake of the obstacle.