A pump monitoring system includes a controller and a microphone for detecting sound waves. The controller is configured to receive an audio signal from the microphone representing sound waves generated by the vacuum pump. The controller processes the received audio signal to generate a frequency domain representation of the audio signal. The frequency domain representation of the audio signal is analysed to identify at least one fault condition frequency component indicative of a fault condition. A fault condition signal is output to identify the fault condition in dependence on the identification of the at least one fault condition frequency component. In a further embodiment, the pump monitoring system comprises a vibration sensor for detecting vibrations. The present invention also relate to a vacuum pump; a method of monitoring a vacuum pump; and a nontransitory computer-readable medium.

An aircraft propulsion unit including two distinct fan spools, and including a first duct and a second duct extending downstream of the two fan spools, the propulsion unit including a control ring disposed on one of the ducts, downstream of one of the fan spools, with at least one annular internal wall extending in an interior space of the duct, the control unit of the control ring being configured to modify the shape of the internal wall, and to cause an air passage cross section in the duct to vary at the ring, a device for acquiring acoustic signals generated by acoustic waves propagating downstream of the fan spools, and a device for processing the acoustic signals, configured to measure a dephasing between the acoustic waves and to control the control ring depending on the dephasing.

A test bench for turbomachine comprising: an installation zone for turbomachine; an active system for attenuating the noise emissions produced by the turbomachine. The active system includes an attenuation zone with emitters such as loudspeakers; a first microphone placed downstream of the turbomachine; and a second microphone placed downstream of the attenuation zone. The system reduces the turbomachine waves on the basis of the measurements from the first microphone and from the second microphone. The invention also proposes a method for attenuating the noise emissions from the turbomachine tested in the test bench.

A signal processing apparatus includes a CPU which executes an input step of receiving an input of a measurement value of a target parameter at a first time, in which noise is superimposed on a true value of the target parameter, a calculation step of calculating a variation amount of the measurement value of the target parameter at the first time, based on a maximum likelihood estimate of the target parameter at a second time and calculating a maximum likelihood estimate of the variation amount, and an output step of outputting a value obtained by adding the maximum likelihood estimate of the variation amount to the maximum likelihood estimate of the target parameter at the second time, as a maximum likelihood estimate of the target parameter at the first time.

A system for identifying timeframes for borescope inspections for a gas turbine engine, having: monitoring systems monitor engine conditions, derive engine condition information and communicate such information to processors; feature interpreter module electronically communicates (i) with processors to process engine condition information, and (ii) feature interpreter information to processors, such information defines a probability of a FOD event; accumulator module electronically communicates (i) with processors to processes feature interpreter information, stored information since a last borescope inspection, and (ii) accumulator information to processors, such information defines an accumulated probability of a FOD event; and predictor and inspection planner module electronically communicates (i) with processors to processes accumulator information and stored information defines a threshold limits for a probability of a FOD event, and (ii) predictor and inspection planner information to processors, such information identifies a timeframe for a next borescope inspections predicted to occur before a FOD event.

An apparatus includes a computer enclosure with a first fan, a second fan, a fan controller, and an input for receiving a signal from a microphone indicating an amount of noise at a target location. The apparatus further includes a first actuator coupled to the first fan for adjusting an axial position of the first fan, wherein the controller controls the operation of the first actuator to position the first fan to reduce the noise indicated by the signal from the microphone with the first and second fans in operation. The microphone senses sound pressure and the controller automatically adjusts a position of one or more fans using an actuator to change the distance from the fan to the microphone, which may be co-located with a user, to provide destructive interference at the location of the microphone.

Methods, apparatus, systems and articles of manufacture are disclosed for closed loop control of a gas turbine. An example apparatus includes a frequency band splitter to separate a combustion pulsation signal into a plurality of frequency bands. The example apparatus includes a plurality of subcontrollers, each subcontroller corresponding to one of the frequency bands. Each subcontroller is to be activated at an amplitude threshold associated with the normal operating set point of the frequency band and to generate a correction value while the corresponding frequency band is operating beyond the amplitude threshold. The example apparatus includes a net correction output calculator to aggregate the correction values to generate an aggregated correction value. The example apparatus includes a subcontroller limiter having a maximum limit and/or a minimum limit to inhibit subcontroller(s) from increasing their respective correction values when aggregated correction value is to exceed the maximum limit and/or minimum limit.

The present disclosure provides a centrifugal blower assembly that includes a centrifugal fan and a scroll casing housing the centrifugal fan. The scroll casing includes a scroll starting position, a scroll ending position and an air passage extending between the scroll starting and ending positions. The scroll ending position is downstream from the scroll starting position relative to airflow through the scroll casing. The centrifugal blower assembly further includes an air outlet extending from the scroll ending position and a plurality of resonators mounted on an exterior surface of the air outlet. Each of the plurality of tuned resonators has respective cavities in fluid communication with inside of the air outlet. Each of the cavities has respective different volumes, heights, widths, and/or lengths from each other.

Methods and systems for processing a signal indicative of at least one operating condition of a gas turbine engine to remove noise associated therewith are provided. The method and systems receive a signal from one or more sensors operably coupled to a gas turbine engine, retrieves one or more known system parameters and a previously determined average signal, and processes the signal using the system parameter and the previously determined average signal to remove noise therefrom. In some of the described methods and systems, the processed signal is then compared to predetermined upper and lower limits, and, if the processed signal exceeds the limits, at least one component of the gas turbine engine, such as a fuel-flow split, is adjusted in an effort to bring the signal back within the limits.

A method includes sensing sound pressure at a specified location, and a controller automatically adjusting a position of one or more fans among a plurality of fans to reduce the sound pressure sensed at the specified location. The position of the one or more fans may, for example, be adjusted using an actuator to change the distance from the fan and the specified location, which may be a location of a user. Optionally, the method may further include the controller automatically adjusting a speed of one or more fans among the plurality of fans to reduce the sound pressure sensed at the specified location. The position and speed of one or more fans may be adjusted to provide destructive interference at the specified location.