Gas turbine engine with airflow measurement system
AssigneeROLLS-ROYCE plc
InventorsVasileios KYRITSIS, Maurice BRISTOW, Peter LOFTUS
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Abstract
A turbofan gas turbine engine having a bypass duct, and a bypass airflow measurement system. The bypass airflow measurement system comprises: at least one acoustic transmitter configured to transmit an acoustic waveform across the bypass duct of the gas turbine engine though which a bypass airflow passes to at least one acoustic receiver; where the at least one acoustic transmitter and the at least one acoustic receiver are located on an axial plane that is substantially perpendicular to the bypass flow. A method of measuring bypass airflow properties of a turbofan gas turbine engine is also described.
Claims16
A turbofan gas turbine engine having a bypass duct and a bypass airflow measurement system, the bypass airflow measurement system comprising:
- at least one acoustic transmitter configured to transmit an acoustic waveform across the bypass duct of the gas turbine engine though which a bypass airflow passes to at least one acoustic receiver;
- where the at least one acoustic transmitter and the at least one acoustic receiver are located on an axial plane that is substantially perpendicular to the bypass flow.
A method of measuring bypass airflow properties of a turbofan gas turbine engine having a bypass duct, the method comprising the steps of:
- (a) providing at least one acoustic transmitter configured to transmit an acoustic waveform across the bypass duct to at least one acoustic receiver, wherein the at least one acoustic transmitter and the at least one acoustic receiver are located on an axial plane (63) that is substantially perpendicular to the bypass flow;
- (b) determining a transit time for the wave form travelling from the at least one acoustic transmitter to the at least one acoustic receiver;
- (c) determining a velocity of bypass airflow from the transit time along each line of sight between each pair of acoustic transmitter and acoustic receiver;
- (d) calculating an overall average bypass airflow velocity by a weighted sum of the individual airflow velocities derived for each line of sight;
- and
- (e) using the average bypass airflow velocity as a constituent element of a power setting parameter for the turbofan gas turbine engine, the power setting parameter being non-dimensionalised relative to a reference temperature.
Dependencies are inferred from the claim text.