Monitoring oil condition

This project aims to build a prototype system for in-flight oil condition monitoring for civilian engines, specifically for gearboxes, which are an essential feature in the next generation of ultra-high bypass ratio (UHBR) turbofan engines. The conditions which customers are seeking to monitor are contamination, such as water, and deterioration in the properties of the oil. Technologies currently exist to measure these condition in ground-based labs but the challenge is to monitor oil during flight, generating data which can be used to improve the understanding of what is happening during a flight and form the basis of improvements for maintenance.

The core technology consists of a thin film platinum sensor that delivers a small pulse of heat to gearbox oil and, simultaneously, measures the rate of heat absorbed by the oil. The heat pulse last a few milliseconds and the resulting temperature rise is less than 2 degrees Celsius. Based on the measured rate of heat absorption, thermal properties of the oil can be inferred with extreme accuracy, namely the product of density, heat capacity, and heat conductivity. This quantity is known as "thermal product" and the technique was developed and patented by Oxford University