Numerical study of catalytic converter geometries and their impact on exhaust back pressure and energy conversion in engine exhaust systems using parametric simulation: insights into non-equilibrium thermodynamics

In this investigation, the principles of non-equilibrium thermodynamics are employed to investigate the implications of geometric parameters on engine performance and exhaust back pressure in catalytic converters. The effects of components utilized for engine exhaust management on exhaust back pressure and anomalous engine operation have been extensively studied. This study explores how the geometric parameters of catalytic converters influence back pressure in the exhaust manifold through a detailed numerical analysis. Five models of catalytic converter with different geometric parameters at the inlet section, outlet section, inlet cone angle, outlet cone angle, and porous zone were tested to determine the variations in back pressure. For the monolith, a porous region is used where inertia and viscosity are defined by Darcy’s law, and discrete channel simulation is performed using the “Reynolds-average Naiver-Stokes (RANS) equations”, k-ω turbulence model, and a pressure-based solver. The numerical findings revealed that back pressure increased by up to 15 % with the rise in exhaust gas velocity from 0 to 25 m/s. Among the five models, the optimal configuration reduced back pressure by approximately 20 % compared to the baseline model, primarily due to adjustments in the length of the porous zone and conical sections. The outcomes demonstrate that the back pressure rises as the velocity of exhaust gas rises, and the optimization of configurations is determined by the design of the porous zone and conical sections. The findings prove that the efficiency of catalytic converters is considerably enhanced through the role of transport processes of mass, momentum, and energy, as variations in geometric configurations have a substantial effect on back pressure. Ultimately, this research offers valuable insights that could lead to the development of more efficient catalytic converters, thereby enhancing the control of automotive emissions and sustainable environmental practices. Key contributions of this study include a systematic evaluation of back pressure variations across multiple geometries, offering a pathway for enhanced engine performance and reduced environmental impact. The results have practical implications in improving design methodologies for catalytic converters, with potential applications in real-world automotive manufacturing.