May 18-22, 2003
Particulate fouling is defined as the unwanted deposition of particles on heat exchange surfaces. The fouling layer reduces the heat transfer rate and leads to inefficient operation. The net fouling rate is the result of the difference between the deposition rate and the removal rate of particles. One of the mechanisms that contribute to the removal of particles from powdery fouled surfaces is the collision of an incident particle with the fouled surface. In the present study, removal of particles from powdery fouled surfaces due to an incident particle impact is studied numerically and experimentally. A numerical model is developed to study the interaction of an incident particle with a bed of particles. The numerical model is based on the molecular dynamic theory of granular matter. The numerical model is tested for an incident copper particle hitting a bed of particles at different impact speeds. The numerical results are verified experimentally. An experimental setup has been built to study the removal of particles from powdery fouling layers due to an incident particle impact. It is shown that depending on the impact speed, zero, one, two or three particles are ejected from the powdery layer. By comparing the numerical results with the experimental measurements it is shown that the numerical results fit in the measured range of impact mentioned above. The numerical model will be used further to characterize the removal of particles from powdery fouling layers as function of particle size, material, incident particle impact speed and the bed of particles porosity.
M. S. Abd-Elhady, C. C.M. Rindt, J. G. Wijers, and A. A. van Steenhoven, "Removal of Particles from a Powdery Fouled Surface due to Impaction" in "Heat Exchanger Fouling and Cleaning: Fundamentals and Applications", Paul Watkinson, University of British Columbia, Canada; Hans Müller-Steinhagen, German Aerospace Centre (DLR) and University of Stuttgart; M. Reza Malayeri, German Aerospace Centre (DLR) Eds, ECI Symposium Series, (2003). http://dc.engconfintl.org/heatexchanger/18