Gas turbine engine with airflow measurement system
AssigneeROLLS-ROYCE plc
InventorsVasileios Kyritsis, Maurice Bristow, Peter Loftus
Life of this patent
Estimating the term…
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.
Claims17
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, wherein
- 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 airflow, and
- the turbofan gas turbine engine further comprises a bifurcation wall located upstream of the bypass airflow measurement system relative to a direction of the bypass airflow.
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 that is substantially perpendicular to the bypass airflow;
- (b) determining a transit time for the waveform 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 the at least one acoustic transmitter and the at least one acoustic receiver;
- (d) calculating an overall average bypass airflow velocity by a weighted sum of 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, wherein
- the turbofan gas turbine engine further comprises a bifurcation wall located upstream of the at least one acoustic transmitter and the at least one acoustic receiver relative to a direction of the bypass airflow.
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, wherein
- 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 airflow, and
- the turbofan gas turbine engine further comprises a bifurcation wall, a leading edge of the bifurcation wall being upstream of the axial plane, and a trailing edge of the bifurcation wall being downstream of the axial plane relative to a direction of the bypass airflow.
Dependencies are inferred from the claim text.