Experimental evaluation of isentropic efficiency in turbocharger twin-entry turbines

Abstract Turbocharging plays a fundamental role not only in improving the performance of automotive engines, but also reducing fuel consumption and exhaust emissions spark-ignited biofuel, diesel, liquid, gaseous engines. Dedicated experimental investigations on turbochargers are therefore needed to evaluate better understanding its performance. The availability information steady flow turbocharger is an essential requirement optimize matching calculation. It interesting know isentropic efficiency turbine order improve coupling with engine, particular it difficult identify definition through direct evaluation. In radial turbine, efficiency, evaluated directly starting from measurement thermodynamic quantities at inlet outlet sections, can be affected by significant errors. This inaccuracy mainly related incorrect evaluation temperature, due non-uniform distribution field section. For this purpose, conditioner was installed downstream turbine. Tests were performed different values rotational speed, quasi-adiabatic conditions. de-coupler analysed hand-made three-hole probe exposed junction thermocouple inserted pipe protrusions. Thanks campaign, possible measure pressure, velocity, mass temperature profiles necessary examine homogeneity field. As fitted twin entry have been properly taken into account referring each sector.