Exergy-Based Energy Efficiency Analysis of the Pneumatic Drive with Controlled Braking and Compressed Air Recuperation

The main objectives of the study are to develop a methodology for calculating the energy efficiency of a pneumatic drive with controlled braking and compressed air recuperation based on a three-dimensional CFD model, as well as to optimize the control algorithm of the pneumatic system operating mode in order to maximize the utilization of the internal energy of the working medium. To achieve these objectives, the following tasks were accomplished: mathematical modeling of pneumatic drive dynamics was performed to determine the energetically justified switching point to the braking mode; the rational structure of switching connections between cylinder chambers was optimized to ensure implementation of compressed air recuperation into the supply line; three-dimensional modeling of unsteady gas-dynamic processes was carried out in ANSYS Fluent using a dynamic mesh; an exergy-based approach to assessing the system’s energy balance was implemented. The most significant results include the development of a three-dimensional model that enables accurate determination of the pressure in the exhaust chamber; quantitative confirmation of the substantial influence of temperature fluctuations and internal energy redistribution on the efficiency of the pneumatic drive; refinement of the actual pressure level in the exhaust chamber and the mass flow rate of the recuperated air; and obtaining an exergy efficiency value of 48.37%, which is 1.5 times higher than the result calculated using a simplified isothermal model. The significance of the obtained results lies in the development of a scientifically substantiated methodology for calculating the energy efficiency of pneumatic drives based on three-dimensional modeling of transient processes.