Experimental approach of surface pressure measurements on additive manufactured nozzle guide vane in a turbocharger turbine

Obtaining the surface pressure measurement of the pneumatic blades in turbomachinery is beneficial in understanding the flow mechanism around the blades and designing of the blades to improve the turbomachinery performance. However, it is difficult for the turbocharger turbine due to the space limitation, high rotational speed, and small geometric size. The present study investigates a novel measuring approach of the surface pressure of the guide vane in a turbocharger turbine based on the additive manufacturing techniques, which is not reported in the previous literature. The static pressure on the pressure side and suction side of the guide vanes in the variable nozzle turbine was investigated using both the experimental and numerical methods. The results show that the majority of the measuring results generally agree with the numerical prediction at different operating points with the relative difference below 5%. Besides, the trends of the static pressure as the rotational speed and mass flow rate between the pressure side and suction side were also captured in the experimental methodology. The highest deviations between experimental and calculated models were found in the first and fifth pressure taps on the guide vanes with an averaged absolute relative difference of up to 11.61% and 16.1% for 20% opening and 60% opening, respectively. The ratio of the kinetic pressure to total pressure and the flow field in the guide vane passage were analyzed to estimate the influence on the static pressure measurement. Nevertheless, the preliminary comparison results still encourage and extend the bounds of the possibility in the use of additive manufacturing techniques for miniature pneumatic blade surface pressure measurement.