An Additively Manufactured Four-Sensor Fast Response Aerodynamic Probe

Abstract

This work describes the design, development and testing of a miniature FRAP with 4 sensors, able to perform measurements in unsteady 3D flow field. Moreover, the calibration and first results with the newly developed probe is provided. The miniature FRAP-4S demonstrates a 3 mm tip diameter, which represents a 25% reduction, in comparison to a first generation FRAP-4S, without any loss in measurement bandwidth. The 3 mm outer probe-cell is additively manufactured with a binder jetting technique. In terms of aerodynamic performance, the probe demonstrates high angular sensitivity up to at least ±18° incidence angle in both directions. Evaluating the measurement accuracy of the newly developed FRAP, measurements are performed at LEC in both a round axisymmetric jet and 1.5-stage, unshrouded and highly-loaded axial turbine. Turbulence measurements are compared against hot-wire studies in round free-jets found in literature. Good agreement in trends and absolute values is demonstrated. Moreover, the performance of the probe is compared against miniature pneumatic and FRAP-2S probes. The results indicate that FRAP-4S, despite its larger size in comparison to the other probes tested, can resolve the main flow patterns, while highest deviations occur in highly skewed and sheared flows. Furthermore, the additively manufactured probe was proven robust after more than 50 hours of testing in representative turbine environment configuration. Finally, the newly developed FRAP reduces measurement time by threefold in comparison to FRAP-2S, which directly translates to reduced development time and thus cost, during turbomachinery development phase.

Uncertainty quantification for aerodynamic pressure probes, using adaptive quasi-Monte Carlo

“…To perform the analysis in the current study we use a FRAP equipped with two pressure sensors (FRAP-2S) and a pneumatic 5-hole probe (5HP), as illustrated in figure 1. This inhouse technology has been under intense development for more than two decades at LEC at ETH Zürich [6,[21][22][23][24]. The pneumatic probe demonstrates a cobra shaped, 0.9 mm tip diameter, similar to the instrumentation used in [25].…”

“…In the context of turbomachinery testing, pneumatic and unsteady pressure probes (UPPs) are widely used in research and industrial testing, since the technology is well-established and requires inexpensive equipment, with minimal rig modifications. For these reasons, there has been a renewed interest in the development and application of UPPs for turbomachinery applications [4][5][6][7]. Moreover, there is ongoing development on the data-reduction methodologies and pressure probe instrumentation [4,8,9].…”

Experimental investigation of geometry effects and performance of five-hole probe in measuring jets in crossflow

“…Wall proximity and interaction of probe with passage flow are effects of specific interest for turbomachinery applications that have also been studied [7,8]. Chasoglou et al [9], in a recent study investigated parametrically different geometrical factors that influence the performance of four-and five-hole stem probes.…”