Development and Validation of a Methodology for Numerical Calibration of Five-Hole Probes

Understanding flow phenomena in turbomachinery poses an ongoing challenge, demanding precise characterization of the flow field in the respective domain. Pneumatic multihole probes are an important tool for such measurements, quantifying flow parameters such as pressures, angles, and Mach numbers. To support the designer of state-of-the-art turbomachinery, it is necessary to reduce the measurement uncertainties associated with the usage of these types of probes in real operating conditions. Numerical investigations can be used to investigate probe behavior under flow conditions that are experimentally unattainable during calibration. Building upon a previous paper, a numerical model incorporating real geometries is developed for numerical calibration. Five approaches of modeling spherical five-hole probe geometries are compared, including a real geometry scan with a resolution of 0.005 mm generated with a Micro CT. Meshes of these geometries are generated using Ansys Fluent Meshing. The flow field around the probe head and inside the probe holes is resolved using Fluent 2024.R1. From the resulting probe hole pressures, calibration coefficients are calculated and compared to experimental data. For well-resolved geometries, numerically generated calibration data exhibit similar quality compared to experimental data. A flow field analysis provides insights into the complex vortex structures and their behavior inside the probe holes, emphasizing their impact on pressure measurements. The developed methodology can enhance the understanding of measurement uncertainties in turbomachinery and can potentially extend calibration maps into new dimensions.     «

Understanding flow phenomena in turbomachinery poses an ongoing challenge, demanding precise characterization of the flow field in the respective domain. Pneumatic multihole probes are an important tool for such measurements, quantifying flow parameters such as pressures, angles, and Mach numbers. To support the designer of state-of-the-art turbomachinery, it is necessary to reduce the measurement uncertainties associated with the usage of these types of probes in real operating conditions. N...     »