Abstract
Under increasingly stringent environmental regulations (Euro 5 / Euro 6), the development of efficient and cost-effective technologies for reducing particulate matter emissions from diesel engines remains highly relevant [1]. This study provides a theoretical substantiation of the first block of a modular exhaust gas cleaning system – the ultrasonic coagulation unit – designed to promote the agglomeration of fine particles and enhance their gravitational deposition. The unit is intended for use within a combined ultrasonic-laser system, in which ultrasonic treatment creates favorable conditions for subsequent laser-based thermal and photochemical effects. The cleaning efficiency is evaluated using a smoke reduction criterion. Based on similarity theory and the Buckingham π theorem, a system of dimensionless criteria is derived and reduced to three generalized parameters: energetic, time-hydrodynamic, and geometric-spatial. A calculation methodology for determining the operating parameters of the ultrasonic unit is developed, including the residence time of the flow in the acoustic zone, the effective interaction length, the module spacing and number, as well as power distribution among the emitters. It is shown that the effective length and the optimal number of emitters determine the modular configuration of the first block, ensuring scalability and adaptability of the system to different engine operating regimes.