Abstract
This study is aimed at improving the operational efficiency of the MMZ D-245.9 diesel engine by enhancing its turbocharging system. The study focuses on the TKR 6.1 centrifugal compressor, which has been modified to incorporate an adjustable inlet guide vane assembly developed based on Patent RU2293220C2. The research employs mathematical modeling, thermodynamic analysis, and CFD simulation methods to evaluate the effect of preliminary air swirl on the flow structure in the impeller blade passages and on the energy exchange parameters in the flow path. It has been established that the standard compressor geometry under nominal operating conditions is characterized by a critical angle of attack of +12.85°, which causes flow separation, increased hydraulic losses, and a decrease in adiabatic efficiency. As a result of parametric optimization, a rational blade setting angle of the inlet guide vane apparatus (45°) was determined, ensuring shockless flow entry, stabilization of the flow structure, and an increase in adiabatic efficiency by 16.1%. Thermodynamic calculations showed a decrease in charge air temperature by 16.7 K and an increase in its density by 0.65%. Comprehensive aerodynamic improvement of the unit provides a 5.4% increase in the effective engine power while simultaneously reducing specific fuel consumption by 2.4%, confirming the scientific novelty and practical significance of the research for transport and agricultural machinery operating under various climatic conditions.