Rolls-royce Corporation

Virginia Tech Intellectual Properties, Inc.

Virginia Polytechnic Institute and State University

Peter Loftus

Vasileios Kyritsis

Maurice Bristow

Kevin Todd Lowe

Colin J Parrish

Todd Lowe

Kevin Lowe

A method of thermodynamic assessment of flow through a turbomachine having a compressor, comprising: receiving sensor readings from a plurality of acoustic sensors located about an intake for the turbomachine upstream of the compressor; and receiving pressure and stagnation temperature readings for the flow into the intake. A static temperature is determined for the flow into the intake and an average velocity of the flow over a flow area of the intake upstream of the compressor using the acoustic sensor readings. A mass flow rate of the flow through the intake is determined using the average velocity of the flow and the stagnation pressure.

Flow measurement for a gas turbine engine

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.

Gas turbine engine with airflow measurement system

A flow machine having a flow passage and an air flow measurement system comprising a plurality of acoustic sensors. The acoustic sensors comprise at least one acoustic transmitter configured to transmit an acoustic waveform through the airflow passing through the flow passage to an acoustic receiver. At least one of the acoustic sensors is rotatable relative to one or more other acoustic sensor.

A turbomachine having an air flow measurement system. The system comprises a plurality of acoustic sensors upstream of a compressor of the turbomachine. The acoustic sensors are configured to transmit acoustic waveforms through an intake airflow to further acoustic sensors. The acoustic sensors are located in a single plane and mounted at angular spacing about a central axis of an intake.

A method is provided for determining vibration frequencies of rotating blades mounted on a rotor which rotates relative to and is supported by a rotor support structure. The method includes the steps of:

Determination of blade vibration frequencies and/or amplitudes

A rotor system is provided whereby a rotary assembly such as a fan blade combination in a jet engine is brought into rub contact with a casing such that sensors detect vibration. The casing is then retreated in order to open the gap to a desired value for engine performance. In such circumstances, the rub contact position is defined as a base datum reference from which distance the casing is displaced in order to provide the specified gap for engine performance and efficiency.

Displacement casing

A method of characterizing the vibration of a plurality of rotating blades ( ), such as turbine blades in a gas turbine engine, includes the steps of providing a single strain gauge ( A) on a single one ( A) of the blades and providing either one or two tip timing probes ( A, B) on a casing surrounding the blades. The data from the strain gauge ( A) allows the vibration of the single blade ( A) to be fully characterized while the data from the tip timing probes ( A, B) allows the amplitudes or velocities of vibration of all the blades to be determined. The relationship between the data from the tip timing probes for the single blade ( A) and the stress data from the strain gauge may be established. This relationship may then be assumed to apply to all the blades, thus allowing the stresses induced in all the blades by the vibrations to be determined.

Analyzing vibration of rotating blades

A fluid temperature measuring device (10) comprises a substrate (12) upon which is deposited a first insulating layer (14). A first metallic layer (16) is sputtered onto the first insulating layer (14), a second insulating layer (18) is deposited on the first metallic layer (16) and a second metallic layer (20) is sputtered onto the second insulating layer (18). The second metallic layer (20) is thin and has a low heat capacity so that it responds quickly to changes in temperature of the fluid. The first metallic layer (16) is thin and is heated by supplying an electric current from an electrical power supply (22) to maintain the first metallic layer (16) at the same temperature as the second metallic layer (20). The second metallic layer (20) is electrically connected to an electrical resistance measuring device (24) which detects temperature changes of the fluid by detecting corresponding changes of the electrical resistance of the second metallic layer (20).

Fluid temperature measuring device

A device for detecting axial movement of a rotating member, for example a compressor rotor of a gas turbine engine, comprises a conducting wire spaced radially from the rotating member, and a magnet carried by the rotating member passes in proximity to the conducting wire when the rotating member is rotating. The conducting wire has a first limb a second limb and a third limb extending with axial and circumferential components, the first and third limbs extending in the circumferentially opposite direction to the second limb to increase resolution between pulsed e.m.f.'s produced when the magnet crosses the limbs. The first, second and third limbs are each formed from a pair of parallel connected bars to produce positive and negative pulsed e.m.f.'s which form zero crossing points which are more easily detected. This enables operation at greater radial clearance or lower rotating speeds.

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Derby, United Kingdom

Peter Loftus