ROTOR TIP CLEARANCE

摘要

A method of characterising mechanical and thermal growth of a rotor tip clearance arrangement and a method of controlling such an arrangement. The characterisation method comprising constructing a finite element model and calibration cases; run the model for the calibration cases to obtain displacements; and calculating component growth therefrom. The growth is characterised and scaled for the operating conditions. The clearance is calculated in a time step from the growths and input to a control arrangement for subsequent time steps.

主权项

1. A method of characterising mechanical and thermal growth of a rotor tip clearance arrangement (78), comprising steps to:
a. construct a finite element model (48) of components in the rotor tip clearance arrangement (78); b. define reference points (A, B, C, D) on components in the model (48); c. define calibration cases (60) for the model (48); d. run the model (48) for each calibration case (60) and record displaced position (dA, dB, dC, dD) of each reference point; e. calculate component growth from the reference points (A, B, C, D) and displaced positions (dA, dB, dC, dD); f. characterise the component growth as comprising mechanical growth and thermal growth; g. interpolate mechanical growth and thermal growth between calibration cases (60); and h. output a mechanical growth and thermal growth characterisation map.