The air-side pressure drop of fin-and-tube heat exchangers will increase when covered with dust particles. In this paper

a visual experimental rig was set up to investigate the particle deposition and pressure drop characteristics. The slit fin-and-tube heat exchangers were selected as the test samples. The air velocity ranged from 1.0 to 2.3 m/s and the particle concentration ranged from 2.1 to 10.8 g/m3. The results indicate that dust particles mostly deposited on the windward side of slit fins and the front part of tubes. High air velocity is beneficial to the particle deposition and can increase the air-side pressure drop; the maximum particle deposition weight and the maximum increase of air-side pressure drop increased up to 98.4% and 93.8% respectively in the experimental conditions. High particle concentration can promote the particle deposition and increase the air-side pressure drop; the maximum particle deposition weight and the maximum increase of air-side pressure drop increased up to 22.8% and 28.6% respectively in the experimental conditions. The air-side pressure drop tended to stability more quickly than particle deposition weight in the particle deposition process.