Hans Ejsing Jørgensen

Field experiments with dispersion of pressure liquefied ammonia

Abstract This paper presents dispersion experiments with continuous releases of liquefied ammonia carried out during the CEC ENVIRONMENT project “Fladis Field Experiments”. The source was a horizontal flash boiling jet with release rates of 0.25–0.5 kg s−1. The objective was to study the dispersion in all its stages at the source, in the heavy jet with aerosols, the slightly stabilized plume, and further downstream into the regime of passive dispersion. The concentration field is analyzed in a fixed frame of reference as well as a frame of reference moving with the instantaneous plume centre-line. Empirical probability functions and a spatial correlation of the concentration fluctuations are found, and the enthalpy balance of the cold heavy jet and the aerosol composition are evaluated.

Test of a New Concentration Fluctuation Model for Decision-Makers

It is well known that changes in meteorological conditions also change air pollution levels. But even under apparently constant meteorological conditions still fast and random concentration fluctuations exist due to the turbulent motion of the atmosphere. Dispersion models of today can estimate reasonable accurate one-hour average concentrations for operational use. Operational models describing concentrations on shorter averaging times are needed for assessing odour problems, nonlinear toxic effects, risks of infections, risks of explosions, and fast atmospheric chemistry.