Reducing Particle Deposition in Air-Cooled Heat Exchangers

Analysis of skim milk powder deposition on stainless steel tubes in cross-flow

“…Abd-Elhady et al [3] developed the concept of a dimensionless rolling moment, which is defined as the hydrodynamic rolling moment divided by the adhesion resting moment, to calculate a limiting fouling velocity that theoretically predicts the onset of fouling, and shows close agreement with lab-scale experimental results [4]. The literature contains a variety of methods that reduce fouling by increasing the air turbulence and wall shear stress, such as placing inserts between tubes [5], adding a non-heat transferring "spoiler" tube row at the front of a compact heat exchanger [6], and using non-standard shaped tubes Paz et al [7] focused on fouling in diesel exhaust gases and showed the close relationship between wall shear stress and deposition. Using this link between wall shear stress and fouling, Walmsley et al [8] developed CFD (Computational Fluid Dynamics) models to examine a wide range of tubes for their fouling, heat transfer and pressure drop characteristics.…”

Heat Transfer and Pressure Drop Under Dry and Humid Conditions in Flat-Tube Heat Exchangers With Plain Fins

“…At the same time, the area available for flow is decreased, which results in higher fluid velocity. This, in combination with a rougher surface, leads to increased pressure drop [8]. Condensation of water vapor on a heat exchanger surface might have a similar effect.…”