Investigation of a Multi-Tube ESP: CFD-Based Electric Field and Efficiency Decrease During Long-Term Operation

This study focuses on the development, simulation, and experimental validation of a multi-tube electrostatic precipitator (ESP) designed for small-scale heat source applications. Using computational fluid dynamics (CFD), the particle mass concentration and electric field distribution were simulated to determine key operational parameters, including the onset voltage for corona discharge. ESP efficiency was evaluated through gravimetric measurements of particulate matter (PM) concentrations during short-term and long-term operations. Short-term tests at a supply voltage of 8.7 kV demonstrated an average PM capture efficiency of around 84%. In long-term operation, with an increased voltage of 12.5 kV, the ESP initially achieved efficiencies close to 90%. However, a gradual decline in performance was observed, with efficiency dropping to approximately 82% after 33 hours of continuous operation. The efficiency decrease was attributed to the accumulation of PM on the collection surfaces, which led to reduced electrostatic field strength and diminished particle capture capability. These results emphasize the necessity of regular cleaning to maintain high-efficiency operation, especially in extended-use scenarios. When properly maintained, the multi-tube ESP used in this work has the potential to reach high efficiency similar to existing small-scale ESP systems.