Experimental Study of Particle Deposition in Bends of Circular Cross Section

The deposition efficiency of liquid particles in tube bends of circular cross section has been measured for flow Reynolds numbers of 100, 1000, 6000, and 10,000. The particle Reynolds number, Re p , was in the range 0.6-3.9 for the laminar flow cases (i.e., Re = 100 and 1000), whereas for the turbulent flow cases (i.e., Re = 6000 and 10,000) Re p was in the range 1.3-12.7. Bends constructed of stainless steel and glass tubes of different diameters were used. The experiments were performed using monodisperse aerosols generated by the vibrating orifice aerosol generator. The results were in good agreement with the theory of Cheng and Wang for Re = 1000, but differed from theory for Re = 100. For the turbulent cases, no dependence was found on the flow Reynolds number and an exponential curve of deposition efficiency versus Stokes number was fitted to the experimental results. A theoretical justification of the form of the curve is given in the paper.