Lubricant System Interaction Simulator
The assessment of lubricant ageing has been traditionally carried out with short duration bench scale tests where a small amount of lubricant is exposed to temperatures that are higher than gas turbine operating conditions to promote accelerated degradation. This type of testing results in chemical compositions that do not correlate with in-service lubricant samples. A more reliable method for such testing is to use testbed engines, but the significantly higher operating costs and limited time durations do not allow representative ageing tests where the chemical composition of the ageing lubricant can reach equilibrium.
There is a need for a test method that lies between bench scale and testbed engines, which can allow cost effective testing in an environment that is closely matched to that of aviation gas turbines. The LSIS (Lubricant System Interaction Simulator) was designed and built by Rolls-Royce plc and it is a unique test facility that addresses all these issues. It is now situated in the Department of Mechanical Engineering at the University of Sheffield UK, and is a part of the LCCC. The LSIS is based on a modular design concept where components can be added in series or parallel to a main flow circuit, so that the different components of a gas turbine can be simulated. In this way, realistic lubricant degradation conditions can be achieved towards the investigation of the interactions between a single or multiple components of a gas turbine and the lubricant itself. Furthermore, accurate control of parameters such as temperature, heating input and flow rates can be accurately controlled resulting in a facility that can run for thousands of hours with minimal user supervision.