Method of analysing blade tip timing and a displacement system

摘要

A method of analysing blade tip timing data obtained from an array (P k ) of stationary timing probes (3) that are spaced at integer multiples of a base angle. Replace one of the probes (3) with a virtual probe (P v ) to give a virtual probe set (42). Set an initial probe angle (¸ v ) and an initial engine order (EO v ) for the virtual probe (P v ). Calculate the condition number (CN) for the virtual probe set (42). If the condition number (CN) at least meets a threshold criterion, solve the virtual probe set (42) for blade tip displacement amplitude. Else increment the virtual probe angle (¸ v ) and/or the virtual engine order and iterate from calculating the condition number. Else reinstate the replaced probe (3) and replace a different probe (3) from the array of probes (P k ) with the virtual probe (P v ); then iterate from setting the initial virtual probe angle and engine order.