摘要:
The invention relates to a device (1) at least for an acoustic temperature measurement in a gaseous medium (M) passing a medium channel (110) by means of runtime measurement of an acoustic pulse (AP) running through the gaseous medium (M) from at least a first transmitter arrangement (TA1) to at least a first receiver arrangement (RA1), the first transmitter arrangement (TA1) comprising a sound pulse generator (2) for the generating the acoustic pulse (AP), which is connected by a first acoustic channel (3) to a transmitter (4) which transmits the acoustic pulse (AP) into the medium (M), the first acoustic channel (3) being of acoustically dispersive design, and, the first receiver arrangement (RA1) comprising a receiver (5) for receiving the acoustic pulse (AP) after it has passed through the medium (M) and for transmitting it via a second acoustic channel (6) to a first microphone (7), preferably a piezoelectric microphone (7), for detecting the acoustic pulse (AP), the first acoustic channel (3) being curved towards the sound pulse generator (2) in such a way that the radiant heat of the medium (M) on the sound pulse generator (2) is at least greatly reduced, wherein at least the transmitter (4) comprises in the first acoustic channel (3) on its side (41) facing the medium (M) to be measured interfering element (42) which reflects a part (RI) of the acoustic pulse (AP) back into the first acoustic channel (3) of the first transmitter arrangement (TA1), in which a second microphone (8), preferably arranged on the side (43) of the transmitter (4) feeing the sound pulse generator (2), is arranged for detecting the back-reflected part (RI) of the acoustic pulse (AP), the device (1) further comprising a pulse discriminator (9) designed to determine the arrival times (AT) of the recorded acoustic pulses (AP) in a suitable way and to transmit them to an evaluation unit (10) designed to determine the temperature of the medium (M) from the runtime of the acoustic pulse (AP) from the transmitter (4) to the receiver (5), taking into account the arrival times (AT) determined by the pulse discriminator and the acoustic pulses (RI, AI) detected by first and second microphones (7,8).
摘要:
Under one aspect, a method of processing a material includes heating a region of the material with a first energy source; exciting an acoustic wave in the material; and transmitting the acoustic wave through the heated region, the heated region changing at least one property of the acoustic wave. The method also can include detecting the change in at least one property of the acoustic wave; characterizing a temperature of the material in the heated region based on the detected change in at least one property of the acoustic wave; and comparing the characterized temperature of the material in the heated region to a threshold. The method further can include, based on the characterized temperature of the material in the heated region being less than the threshold or being above the threshold for an insufficient amount of time, modifying a property of the heated region with a second energy source.
摘要:
In a method of inferring ambient atmospheric temperature, an acoustic signal is emitted from a speaker. A first sample of the acoustic signal is captured with a first microphone spaced a first distance from the speaker. A second sample of the acoustic signal is captured with a second microphone spaced a second distance from the speaker. The second distance is greater than the first distance, and a difference between the first distance and the second distance is a known third distance. A time delay in the acoustic signal is determined between the first sample and the second sample. An ambient temperature of the atmosphere through which the acoustic signal traveled is inferred based on a relationship between the time delay and temperature for the acoustic signal over the third distance.
摘要:
This invention relates to a waveguide with distributed sensors that support travelling ultrasonic wave modes to provide quantitative local distributed sensing of the physical and chemical properties of the medium surrounding the sensor locations and/or the material properties of the waveguide. The plurality of sensor is operably associated with plurality wave mode for probing and identifying plurality of properties simultaneously. The reflected waves are representative of local information about the surrounding media at that sensor location.
摘要:
Thermoacoustic sensors, such as dynamic pressure sensors, in the combustor measure vibratory responses of the combustor. An integrated monitoring and control system controller correlates sensor readings with combustion thermoacoustic properties in order to identify combustion anomalies by wavelet or Fourier analysis techniques; determine bulk temperature characteristics within the combustor with dominant mode frequency analysis techniques; and optionally determines absolute active path temperatures within the combustor with acoustic pyrometry transmission and time-of-flight analysis techniques. In some embodiments all of the monitoring functions are performed with a commonly shared array of thermoacoustic sensors that function as both combustion dynamics thermoacoustic vibration/wave receivers and acoustic transmitters. The monitored combustion properties are used for controlling gas turbine combustion.
摘要:
Acoustic pyrometry-based active temperature monitoring of gas turbine combustors, including industrial gas turbine (IGT) combustors is incorporated into the combustion monitoring and control system by addition of an acoustic transmitter or acoustic transceiver that transmits a sound wave in a line-of-sight with a plurality of thermoacoustic sensors, such as dynamic pressure sensors. Sound transmission time-of-flight is measured by the controller and correlated with path temperature along the line-of-sight. Path(s) of acoustic transmission serve as absolute temperature measurement that optionally is used for calibrating dominant mode passive bulk temperature measurement. In an integrated thermoacoustic pressure-based sensor and monitoring/control system embodiment, the controller correlates performance of an combustion thermoacoustic properties in order to identify combustion anomalies by wavelet or Fourier analysis techniques, determine bulk temperature characteristics within the combustor with dominant mode frequency analysis techniques and determines absolute active path temperatures within the combustor with acoustic transmission and time-of-flight analysis techniques.
摘要:
Disclosed is a method and apparatus for measuring semiconductor substrate temperature using a differential acoustic time of flight measurement technique. The measurement is based on measuring the time of flight of acoustic (ultrasonic) waves across the substrate, and calculating a substrate temperature from the measured time of flight and the known temperature dependence of the speed of sound for the substrate material. The differential acoustic time of flight method eliminates most sources of interference and error, for example due to varying coupling between an ultrasonic transducer and the substrate. To further increase the accuracy of the differential acoustic time of flight measurement, a correlation waveform processing algorithm is utilized to obtain a differential acoustic time of flight measurement from two measured ultrasonic waveforms. To facilitate signal recognition and processing, a symmetric Lamb mode may be used as mode of excitation of the substrate.
摘要:
An apparatus and method for determining temperature is disclosed. An ultrasonic signal is generated that propagates through a buffer and a portion of the signal is reflected at an interface. A time of flight is measured between generating the ultrasonic signal and detecting the reflected portion. The temperature is determined based on the time of flight of the reflected signal.
摘要:
The disclosure relates to a method for determining a temperature in a pressurized flow path of a gas turbine comprising the steps of sending an acoustic signal from an acoustic signal emitting transducer across a section of the pressurized flow path, detecting the acoustic signal with a receiving transducer, measuring the time needed by the acoustic signal to travel from the acoustic signal emitting transducer to the receiving transducer, calculating the speed of sound, and calculating the temperature as a function of the speed of sound, the heat capacity ratio (□) and a specific gas constant (Rspec) of the gas flowing in the pressurized flow path.Besides the method, a gas turbine with a processor and transducers arranged to carry out such a method is disclosed.
摘要:
The present invention provides a system and method for a milk measuring device for measuring the acoustic properties, such as acoustic damping and sound velocity in milk, in order to determine milk properties. The sound velocity in milk depends on temperature and composition. By carrying out, for example by means of a piezo element, a reference measurement on vibrations that have been directed by a second piezo element into a wire or the like of known material, which wire is strung in the measuring chamber which is filled with the milk to be tested, the milk temperature can be derived, so that other milk properties, in particular the fat/protein composition, can be determined in a more reliable manner.