Development of a 12-Hole Omnidirectional Flow-Velocity Measurement Probe

摘要

A new multihole probe for omnidirectional flow measurement has been successfully developed. The probe was designed with a spherical head of 0.375 in. (9.53 mm) and fabricated in brass with stainless steel internal pressure tubing. It was calibrated at multiple Mach numbers in a jet facility and tested to assess its accuracy of prediction of flow variables: three velocity components and static pressure. Only four pressure ports are used at any measurement point, thus avoiding redundancy. This optimum design was made possible by new definitions previously developed by the authors for nondimensional coefficients in multihole probes, which obviate the necessity for a symmetric arrangement of ports. The new probe has the same functionality as an earlier 18-hole design but with many more advantages in terms of spatial resolution, frequency response, and cost, and hence is a persuasive upgrade. The probe can be employed in the entire subsonic regime. Error estimates with experimental data show good prediction capability: 0.5 deg in Θ, 0.7 deg in Φ, and 0.6% in velocity magnitude (95% confidence).