Self-mixing Optical Sensor for Measurement of Blade Vibrations and Tip Clearances

To address the Navys need for ultrahigh temperature (UHT) sensors for gas turbine engine applications, Physical Optics Corporation (POC) proposes to develop a new Self-mixing Optical Sensor (SOS) for measurement of blade vibrations and tip clearances. This proposed solution is based on a sensing probe fabricated of UHT-resistant ceramics supplemented by POCs proprietary self-mixing interferometry (SMI) technology. Specifically, the innovation in use of p-SiAlCN ceramics and SMI will enable the SOS to survive UHT environments for nonintrusive measurements. The probe will incorporate a replaceable sapphire window, protecting it from oil or debris contamination while withstanding UHTs and high pressures. As a result, this sensor offers high-temperature operation >2500 deg F. The probe will be <0.25 in. in diameter and about 1 in. in length, capable of measuring three-dimensional vibrations and tip clearances of all blades without being affected by the engine case vibrations. In Phase I, POC will demonstrate the feasibility of SOS by fabricating a prototype and testing it in a simulated environment. In Phase II, POC plans to develop an engineering prototype, meeting all Navy requirements and test it in a representative engine environment. The Phase II SOS will reach technology readiness level (TRL)-5.