Improvements to the Propulsion Systems Lab Dynamic Thrust Measurement System at the NASA Glenn Research Center

The Propulsion Systems Lab (PSL) at the NASA Glenn Research Center contains two large engine test cells (PSL-3 and PSL-4) capable of simulating flight conditions up to 70,000 ft with a maximum forward air speed of Mach 3.0. Part of flight simulation consists of accurate thrust measurement. Recently, PSL-3 customers have a need for measurement of the dynamic response from the thrust measurement system. During the collection of dynamic thrust measurements, there was an unwanted response of the thrust system, which made it impossible to collect dynamic thrust data. The data presented in this report demonstrates an improvement in the capability to measure dynamic thrust from a jet engine test article in NASA Glenn’s Propulsion Systems Lab Cell 3. The results show that dynamic thrust can accurately be collected at low frequencies, with the limiting factor being the natural frequency of the test article assembly. This report also demonstrates the ability to measure and model the dynamic response of a large test chamber, with a test article running in the facility. Based on these measurements, one can develop plans to reduce unwanted dynamic response based on computer modeling and field verification.