Turbulent Deposition of Aerosol Particles in Large Transport Tubes

Particle deposition from turbulent flows in large tubes (up to 102 mm) was measured experimentally and a correlation developed for the results. The correlation allows prediction of the nondimensional deposition velocity as a function of the nondimensional relaxation time and the flow Reynolds number. The correlation shows good agreement with previous correlations for deposition in small diameter tubes as well for the full range of tube sizes (13-102 mm diameter) and Reynolds numbers (up to 55,000) upon which the correlation is based. As an example of the improvement in predictive abilities rendered by this new model, the penetration of 20-mm-aerodynamic-diameter aerosol particles in a 102-mm-diameter tube at a flow rate of 2260 L/min was measured to be 59%. The present model predicts a penetration of 62%, while two previously reported models that do not include Reynolds number effects predict 80% and 82% penetration. This new model should be of benefit in the design and evaluation of large-sized transport tubes for continuous monitoring applications.