Influence of wet-particle deposition on air-side heat transfer and pressure drop of fin-and-tube heat exchangers

Abstract

Wet particles have higher propensity to deposit on fin surfaces than dry particles, and may cause a more serious deterioration of the air-side performance of fin-and-tube heat exchanger. The purpose of this paper is to experimentally investigate the influence of deposited wet particles on the air-side heat transfer and pressure drop of heat exchangers. Test samples cover three types of fins, i.e., plate fin, wavy fin and louver fin. Experimental conditions cover the inlet air relative humidity of 50–90%, the inlet air velocity of 1.0–3.0 m s−1, and the particle concentration of 2.1–10.8 g m−3. The results show that wet particles mostly deposit on the leading edge of fins as well as the front part of tubes, and the louver fin is almost completely blocked by the wet particulate fouling. Moreover, the increase of inlet air relative humidity, particle concentration and the decrease of fin pitch reduce the air-side heat transfer and increase the air-side pressure drop after wet particle deposition; the increase of inlet air velocity firstly deteriorates and then enhances the air-side performance; and louver fin is the most conducive to the deterioration of air-side performance.