Design and Calibration of Pneumatic Probes for Aerodynamic Testing

Abstract: To develop turbomachines aerodynamic testing is an important part of the process. The performance testing this thesis will focus on is pressure measurements, which often is done using pneumatic probes. The pneumatic probes used in this project were a five-hole probe, a pitot probe and two different types of Kiel probes. GKN Aerospace had a five-hole probe and a pitot probe that was to be used. The two Kiel probes, however, needed to be designed and fabricated. It was interesting to design an open shielded Kiel probe and a close shielded Kiel probe. The open shielded Kiel probe is more insensitive to the flow angle than the close shielded Kiel probe, but the close shielded Kiel probe could be useful when a rake or grid of probes is needed. In this thesis the total pressure and the sensitivity to the flow angle will be compared between the four pneumatic probes. It will give details of which probes could be useful in which situations. To get all the data necessary there is also other equipment that are needed. The equipment necessary for this project are two servo motors are used to move the probes, scanners are used to measure the pressures, a NI Compact RIO is used as a remote system, an EtherCAT is used to transfer the signals from the computer to the Compact RIO and Labview is used to create the program to control all the components. This equipment was then used to calibrate the five-hole probe and for all the tests in the wind tunnel. The total pressure and the insensitivity to the flow angle could then be compared between the probes. This resulted in an analysis that presented the five-hole probe as a good choice for when the flow angle is unknown. The open Kiel probe is a good choice when a high insensitivity to the flow angle is required and the closed Kiel probe is a good choice when a rake or grid of total pressure probes is required. The pitot probe is a good choice when a cheap probe with low insensitivity to the flow angle is needed.