Welding Fume Buoyant Plume

Abstract

Baum and Mulholland (1979) have published a theory for particle coagulation in buoyant plumes. They used the theory for plumes from smokestacks and from small smoldering sources. Mulholland and Ohlemiller (1982) have also used this theory for smoldering sources. Here, the use of the Baum—Mulholland theory is enlarged and applied to welding fume buoyant plumes. Since welding is a very complicated and not yet fully understood process, it is not possible to measure or calculate all necessary initial parameters for the theory. By using recommended values from Chen and Rodi (1980) and measured plume heights, it was possible by iterative calculations to find the necessary initial plume heat flow. The Baum-Mulholland theory and measured particle concentrations were then used to calculate the particle number flow, the particle number concentration, and the mass flow as functions of plume height. The results make it possible, for instance, to recommend a suitable vertical temperature gradient in a welding room and to quantify requirements for local exhaust systems.