Showing papers on "Ultrasonic flow meter published in 2003"

In-vivo synthetic aperture flow imaging in medical ultrasound

Abstract: A new method for acquiring flow images using synthetic aperture techniques in medical ultrasound is presented. The new approach makes it possible to have a continuous acquisition of flow data throughout the whole image simultaneously, and this can significantly improve blood velocity estimation. Any type of filter can be used for discrimination between tissue and blood flow without initialization, and the number of lines used for velocity estimation is limited only by the nonstationarity of the flow. The new approach is investigated through both simulations and measurements. A flow rig is used for generating a parabolic laminar flow, and a research scanner is used for acquiring RF data from individual transducer elements. A reference profile is calculated from a mass flow meter. The parabolic velocity profile is estimated using the new approach with a relative standard deviation of 2.2% and a mean relative bias of 3.4% using 24 pulse emissions at a flow angle of 45 degrees. The 24 emissions can be used for making a full-color flow map image. An in-vivo image of flow in the carotid artery for a 29-year-old male also is presented. The full image is acquired using 24 emissions.

4D Magnetic resonance velocimetry for mean velocity measurements in complex turbulent flows

Abstract: An adaptation of a medical magnetic resonance imaging system to the noninvasive measurement of three-component mean velocity fields in complex turbulent engineering flows is described. The aim of this paper is to evaluate the capabilities of the technique with respect to its accuracy, time efficiency and applicability as a design tool for complex turbulent internal geometries. The technique, called 4D magnetic resonance velocimetry (4D-MRV), is used to measure the mean flow in fully developed low-Reynolds number turbulent pipe flow, Re=6400 based on bulk mean velocity and diameter, and in a model of a gas turbine blade internal cooling geometry with four serpentine passages, Re=10,000 and 15,000 based on bulk mean velocity and hydraulic diameter. 4D-MRV is capable of completing full-field measurements in three-dimensional volumes with sizes on the order of the magnet bore diameter in less than one hour. Such measurements can include over 2 million independent mean velocity vectors. Velocities measured in round pipe flow agreed with previous experimental results to within 10%. In the turbulent cooling passage flow, the average flow rates calculated from the 4D-MRV velocity profiles agreed with ultrasonic flowmeter measurements to within 7%. The measurements lend excellent qualitative insight into flow structures even in the highly complex 180° bends. Accurate quantitative measurements were obtained throughout the Re=10,000 flow and in the Re=15,000 flow except in the most complex regions, areas just downstream of high-speed bends, where velocities and velocity fluctuations exceeded MRV capabilities for the chosen set of scan parameters. General guidelines for choosing scanning parameters and suggestions for future development are presented.

Velocity measurements at high temperatures by ultrasound Doppler velocimetry using an acoustic wave guide

Abstract: Ultrasound Doppler velocimetry (UDV) was used to measure flow velocities at temperatures up to 620°C. To overcome the thermal restriction of the ultrasonic transducers an acoustic wave guide was used. The acoustic wave guide and the piezoelectric element are combined in the form of an integrated sensor. This approach allowed the first successful application of the ultrasound Doppler technique in liquid metals at temperatures above 200°C. The feasibility of this integrated sensor concept was demonstrated in experiments with metallic melts. Measurements were performed in a PbBi bubbly flow and in CuSn.

Vibration meter and method of measuring a viscosity of a fluid

Abstract: A vibration meter and a method of measuring a viscosity of a fluid flowing through a pipe are disclosed. The vibration meter comprises meter electronics and a transducer assembly with an electromechanical excitation arrangement and with a flow tube which oscillates in operation. A sensor arrangement produces sensor signals representative of inlet-side and outlet-side deflections of the flow tube. An evaluation circuit derives from said sensor signals and from an excitation current generated by an excitation circuit for the excitation arrangement a viscosity value representative of the viscosity of the fluid.

Noninvasive characterization of a flowing multiphase fluid using ultrasonic interferometry

Abstract: An apparatus for noninvasively monitoring the flow and/or the composition of a flowing liquid using ultrasound is described. The position of the resonance peaks for a fluid excited by a swept-frequency ultrasonic signal have been found to change frequency both in response to a change in composition and in response to a change in the flow velocity thereof. Additionally, the distance between successive resonance peaks does not change as a function of flow, but rather in response to a change in composition. Thus, a measurement of both parameters (resonance position and resonance spacing), once calibrated, permits the simultaneous determination of flow rate and composition using the apparatus and method of the present invention.

Venturi augmented flow meter

Abstract: A venturi-assisted flow meter arrangement is disclosed. The venturi is positioned in a pipe or conduit containing the fluid mixture to be measured upstream of the flow meter. The flow meter is preferably a flow rate meter and/or a phase fraction meter. When the fluid mixture is passed through the venturi, it is homogenized or mixed, which can increase the accuracy of the measurements made by the downstream flow meter. Additionally, the venturi can be used to compute the flow momentum of the fluid mixture, which may be used to calibrate or double check the operation of the flow meter, or allow it to compute the phase fraction for a three phase mixture.

Fluid flow measuring and proportional fluid flow control device

Abstract: Embodiments disclosed herein provide restrictive-flow flow measurement devices, valve improvements and signal control devices and processes that control the flow of liquids, including control processes for single-liquid calibration. In some embodiments, a fluid flow device can be calibrated using a single standard calibration fluid. The fluid flow of a first fluid through a flow meter is measured by calculating a first pressure difference between pressures sensed by two pressure sensors of the flow meter. The fluid flow of a second fluid through the flow meter is measured by calculating a second pressure difference between pressures sensed by the same two pressure sensors. A calibration coefficient is determined based upon the relationship between the flow rate, the fluid density and the calculated pressure difference for the first and second fluids. A relationship between the calibration coefficient and the kinematic viscosity of each fluid is then determined and stored.

Ultrasonic transmitter-receiver and ultrasonic flowmeter

Abstract: An ultrasonic transmitter-receiver comprises a piezoelectric body 4 that performs ultrasonic vibration; an acoustic matching layer 3 formed of a material whose density is from 50 kg/m3 to 1000 kg/m3 both inclusive and whose acoustic impedance is from 2.5 × 103 kg/m2/s to 1.0 × 106 kg/m2/s both inclusive; a lower acoustic matching layer 9 formed between the piezoelectric body 4 and the acoustic matching layer 3; and a structure support body 6 that supports the lower acoustic matching layer 9 and piezoelectric body 4 and shields the piezoelectric body 4 from ultrasonic propagating fluid. There is provided a protection part that is in contact with at least a portion of a sidewall of the acoustic matching layer 3. This protection part is formed by a part of the lower acoustic matching layer 9 and is integral with the lower acoustic matching layer 9.

Novel ultrasound based time averaged flow mapping method for die entry visualization in flow of highly concentrated shear-thinning and shear-thickening suspensions

Abstract: In this work a methodology for high-resolution time averaged two-dimensional flow mapping of converging flows was explored. Flow of non-transparent, highly concentrated shear-thinning and shear-thickening suspensions was circulating through the entrance flow adapter with adjustable position of the die entry. The entrance region was scanned with the distance resolution of 2.7 mm ? 1 mm, radial to axial displacement respectively. The time averaged flow map was composed from one-dimensional flow profiles measured along the ultrasonic sensor beam using the ultrasonic pulsed echo Doppler technique. Priory to die entry visualization an investigation of flow properties was performed using a novel in-line non-invasive measuring technique. The method is based on combination of the ultrasound velocity profiler velocity monitoring and pressure difference method. The rheological flow properties were derived from simultaneous recording and on-line analysis of the velocity profiles across the tube channel and related radial shear stress profiles calculated from the pressure loss along the flow channel. For the first time the entrance flow of shear-thickening suspension could be visualized. A comparison between the flow of the investigated model suspensions was qualitatively analysed. This method gives an opportunity for time averaged flow mapping of viscoelastic and viscous, non-transparent, multiphase and highly concentrated fluids.

Multi-measurement vortex flow meter

Abstract: Two-wire transmitters are described in which the required voltage that a control room must supply to the transmitter is lower at high current than at low current, thus freeing up more voltage for other uses, and in which a constant set of operating voltages may be maintained. A corrected pressure in a vortex flow meter may be determined that reflects the mass flow rate. Thus, the mass flow rate may be determined based on the corrected pressure reading and a measured volumetric flow rate. Density may be determined from pressure and temperature using a table containing error values based on a standard density determination and a relatively simple approximation. During operation of a flow meter, the stored error values may be linearly interpolated and the approximation may be computed to determine the density from the stored error value.

Ultrasonic flowmeter and ultrasonic flowmetering method

Abstract: An ultrasonic flowmeter (10) comprises a trigger oscillating apparatus (14); a pulser receiver (16); a transducer (20) responsive to an electric signal from the pulser receiver (16) for emitting ultrasonic pulses toward a measurement line (ML) within a fluid pipe (22); signal processing means (27) for processing an ultrasonic echo signal that is a reflected wave from the transducer (20); flow velocity distribution calculating means (28) for analyzing the processed ultrasonic echo signal to determine the position and velocity of the ultrasonic reflecting body along the measurement line (ML); and flow rate calculating means (29). The signal processing means (27) comprises a filtering part (21) for filtering the ultrasonic echo signal, and an AD converter (17) for performing AD conversion. The trigger oscillating apparatus (14) is adapted to control the timings of signal transmission/reception between the pulser receiver (16) and the AD converter (17), and also adapted to have a predetermined wait time after causing the ultrasonic pulse oscillation and ultrasonic echo signal reception to successively occur a plurality of times. This structure can precisely flowmeter not only fluids that could be conventionally flowmetered but also fluids that are relatively clean and hence conventionally difficult to flowmeter.

Acoustic matching layer, ultrasonic transmitter/receiver, and ultrasonic flowmeter

Abstract: An acoustic matching layer (1) is composed of a first acoustic matching layer (2) having a low density and a slow sound speed and a second acoustic matching layer (3) having a density higher that that of the first acoustic matching layer (2) and a sound speed faster than that thereof. The first acoustic matching layer (2) the acoustic impedance of which is matched with an ultrasonic radiating medium is provided on the radiation medium side and the second acoustic matching layer (3) is provided on the piezoelectric body layer side. As a result, the ultrasonic transmitter/receiver can have a high sensitivity.

Ultrasonic flowmeter and method of measuring flow volume

Abstract: An ultrasonic flowmeter arranged to perform measurement with high accuracy has first and second ultrasonic transducers 1, 2 which transmit and receive ultrasonic waves, and which are placed so as to form a path for propagation of the ultrasonic waves in a flow passage 14 for a fluid, a transmitting section 3 which drives one of said first and second ultrasonic transducers 1, 2, a first matching section 5 which is connected to the transmitting section, and which adjusts the output impedance of the transmitting section, and a receiving section 6 which has an input impedance approximately equal to or lower than the adjusted output impedance, and which receives the ultrasonic wave reaching the other of the first and second ultrasonic transducers. The flow volume of the fluid is measured by detecting a bidirectional-propagation time difference between the ultrasonic waves propagating in the propagation path.

Acoustic matching layer, ultrasonic transducer and ultrasonic flowmeter

Abstract: An acoustic matching layer 1 according to the present invention includes a first acoustic matching layer 2 , which has a low density and a low sonic velocity, and a second acoustic matching layer 3 , which has a higher density and a higher sonic velocity. The first acoustic matching layer 2 , of which the acoustic impedance is matched to that of a medium into an ultrasonic wave is radiated, is provided closer to the medium, while the second acoustic matching layer 3 is provided closer to a piezoelectric layer, thereby increasing the sensitivity of an ultrasonic transducer.

Wet gas measurement apparatus and method

Abstract: An apparatus and method for determining fluid flow velocities of a flow comprising at least two phases in a conduit are disclosed. By measuring a pressure difference between two measurement points and measuring the flow at these measurement points using ultrasonic flow meters, an accurate calculation of the flow rates of the gas phase and liquid phase is allowed.

Doppler type ultrasonic flowmeter, flow rate measuring method using doppler type ultrasonic flowmeter and flow rate measuring program used in this doppler type ultrasonic flowmeter

Abstract: A doppler ultrasonic flowmeter 10A includes: a Udflow unit 13 for calculating the speed of a great number of reflectors 25 contained in a fluid 12 to be measured; a flow-speed distribution calculating element 70 for calculating the flow-speed distribution of the fluid 12 to be measured within a fluid tube 11 by performing computation processing for the flow-speed data of the reflectors 25 received from the Udflow unit 13; a center position detecting element 71 for detecting the center position of the fluid tube 11; a flow-speed distribution calculating member 67 having an area selecting element 72 which allows the user to select a division area within the fluid tube 11 in units of the division area; the flow-speed distribution being calculated for the selected division area using the reflectors 25; and a flow calculating member 68 for measuring the flow by further performing computation processing for the flow-speed distribution of the fluid 12 to be measured. Furthermore, the doppler ultrasonic flowmeter 10A includes a display monitor 39 for displaying the calculation results output from at least one of the flow-speed distribution calculating member 67 and the flow calculating member 68. The present invention having such a configuration provides a doppler ultrasonic flowmeter, a flow measurement method, and a flow measurement program, having the advantage of enabling measurement of the flow-speed distribution and measurement of the flow, regardless of irregularities in the measurement results of the flow-speed distribution.

Ultrasonic flowmeter has an ultrasonic transducer and ultrasound mirror that has an additional flow guide for optimizing the fluid flow over its surface

Abstract: Ultrasonic flowmeter for measuring the flow rate of a flowing liquid or gas has a housing (1) that encloses a measuring section along which a differential time of flight measurement can be made using at least an ultrasonic transducer (2) and a ultrasound mirror (5) for guiding the sound beam. Fluid flow guiding elements are provided in the area of the mirror surface to optimize the fluid flow over the mirror surface. Independent claims are also included for the following:- (a) an ultrasound meter with an ultrasound deflection mirror holder (8) manufactured from two halves separated in a direction parallel to the longitudinal axis of the meter and; (b) an ultrasound meter with an ultrasound deflection mirror holder, mirror and measurement pipe that can be removed and inserted as a unit in the meter.

Experimental investigation of transverse flow estimation using transverse oscillation

Abstract: Conventional ultrasound scanners can only display the blood velocity component parallel to the ultrasound beam. Introducing a laterally oscillating field gives signals from which the transverse velocity component can be estimated using 2:1 parallel receive beamformers. To yield the performance of the approach, this paper presents simulated and experimental results, obtained at a blood velocity angle transverse to the ultrasound beam. The Field II program is used to simulate a setup with a 128 element linear array transducer. At a depth 27 mm a virtual blood vessel of radius 2.4 mm is situated perpendicular to the ultrasound beam. The velocity profile of the blood is parabolic, and the speed of the blood in the center of the vessel is 1.1 m/s. An extended autocorrelation algorithm is used for velocity estimation for 310 trials, each containing 32 beamformed signals. The velocity can be estimated with a mean relative bias of 6.3% and a mean relative standard deviation of 5.4% over the entire vessel length. With the experimental ultrasound scanner RASMUS the simulations are reproduced in an experimental flow phantom using a linear array transducer and vessel characteristics as in the simulations. The flow is generated with the Compuflow 1000 programmable flow pump giving a parabolic velocity profile of the blood mimicking fluid in the flow phantom. The profiles are estimated for 310 trials each containing of 32 data vectors. The relative mean bias over entire blood vessel is found to be 10.0% and the relative mean standard deviation is found to be 9.8%. With the Compuflow 1000 programmable flow pump a color flow mode image is produced of the experimental setup for a parabolic flow. Also the flow of the human femoralis is reproduced and it is found that the characteristics of the flow can be estimated.

Quantitative analysis of the cross-correlation ultrasonic flow meter by means of system theory

Abstract: The physical principles of the ultrasound cross-correlation flow meter are described quantitatively by means of an approach based on system analysis. We extend an earlier theoretical model of Shu (1987 PhD Thesis Universitat Karlsruhe) by accounting for additional characteristics of the turbulent pipe flow and making use of characteristic turbulence parameters. The velocity obtained by cross-correlation of the phase-modulated ultrasound signals can be predicted with the theoretical model as a function of the Reynolds number. These theoretical predictions agree favourably with experimental results. It is shown that the velocity determined by cross-correlation is nearly the 'modal value' of the turbulent velocity profile and, thereby, higher than the bulk velocity in the pipe. The investigations include studies of the influence of a number of parameters that can be varied in a practical set-up. It is shown that a calibration of the system, as it is done in practice, is only valid for a specific set of values of these parameters and restricted to fully developed flow in the pipe.

Ultrasonic transmitter/receiver, process for producing the same, and ultrasonic flowmeter

Abstract: An ultrasonic transmitter/receiver comprising a piezoelectric (2) for transmitting/receiving an ultrasonic wave, and acoustic matching layers (3a, 3b) composed of dry gel. The acoustic matching layers (3a, 3b) are formed of a plurality of dry gel layers having a different acoustic impedance.

Flow averaging tube and method of using same

Abstract: A flow meter of the pitot type. The meter incorporates a series of apertures along a probe body for exposure to a fluid stream. The result is a number of datum which are averaged and correlated to be representative of the flow within a conduit. Aberrations encountered in noncircular ducting or other irregularities are compensated by correction. The disclosure further sets forth the use of an apparatus to effect the measurements.

Sonar-based volumetric flow and entrained air measurment for pulp and paper applications

Abstract: A sona r-based flow measurement technology for simultaneously measuring volumetric flow rate and volumetric percent of entrained air in paper and pulp slurries is described The technology utilizes sonar array processing techniques to perform two independent measurements to characterize the process fluid Firstly, the meter provides mixture volumetric flow by tracking the speed at which naturally occurring turbulent structures convect with the flow past an axial array sensors The flow meter can be implemented either pressure transducers ported directly to the process fluid or with non-intrusive sensors clamped-on to existing process piping Secondly, the meter utilizes the same sensors to determine the speed at which naturally occurring sound propagates through the process fluid The speed of sound measurement provides an accurate and robust measurement of entrained air Utilizing these two first principles based measurements, the sonar flow meter provides total mixture flow rate, while measuring and correcting for entrained air Data is presented that demonstrates the ability of the sonar meter to measure flow rates in single phase flows to within 05% accuracy for flows ranging from 3 to 20 ft/sec in a wide range of diameters Calculations are presented demonstrating the link between entrained air and mixture sound speed indicating that the sonar meter can measure entrained air on a real time basis to an accuracy of better than 01% by volume

Mass flow meter with chip-type sensors

Abstract: A mass flow meter employs discrete chip-type tem­perature sensors (Ul,U2,Dl,D2) to sense a fluid flow rate. The sensor can be a semiconductor chip such as SiC or silicon, or thin film tungsten (28) on an AlN sub­strate (30). The sensors can be distributed symmetri­cally with respect to the conduit (4) through which the fluid flows, and can be connected in a four-sensor bridge circuit for accurate flow rate monitoring. An output from the mass flow meter can be used to control the fluid flow.

Oil-gas-water multi-phase flow adjusting apparatus and oil-gas-water multi-phase flow rate measuring apparatus and measuring method

Abstract: The invention relates to an oil-gas-water multi-phase flow adjusting apparatus, which mainly comprises an inlet accelerating pipe section, a vortex flow guide spiral pipe, a gas circuit exit connection pipe section, a liquid receiving cone, a mixed liquid relief exit connection pipe section and a sampler exit connection pipe section, and which has the function for changing at intervals the flow pattern, the flow state and the components of the oil-gas-water multi-phase flow. The invention also relates to an oil-gas-water multi-phase flow rate measuring apparatus and its measuring method. The measuring apparatus comprises a blind three-way mixing means, a pressure differential type flow measuring device, a single-γ phase volume fraction meter, a dual-γ phase volume fraction meter, an oil-gas-water multi-phase flow adjusting apparatus and a computing system. The measuring method is as follows: the single-γ phase volume fraction meter and the dual-γ phase volume fraction meter measure the gas content GVF and the water content WC respectively; the pressure differential type flow measuring device measures the differential pressure ΔP of the total flow rate; the computing unit computes the oil flow rate Qo, the gas flow rate Qg and the water flow rate Qw.

Ultrasonic flowmeter and ultrasonic flow rate measuring method

Abstract: An ultrasonic flowmeter of the present invention includes: first and second ultrasonic transducers that send and receive an ultrasonic wave and are arranged so as to form a propagation path for the ultrasonic wave in a flow path of fluid; a transmission unit and a reception unit that drive the first ultrasonic transducer and the second ultrasonic transducer such that the ultrasonic wave is sent and received in two ways between the first ultrasonic transducer and the second ultrasonic transducer, and receive the ultrasonic wave; a zero-cross detection unit that measures a propagation time of the ultrasonic wave by subjecting a received signal generated by the ultrasonic wave received in the reception unit to zero-cross detection; and a correction unit that reduces an error in the zero-cross detection caused by noise superimposed on the received signal, in which the ultrasonic flowmeter calculates a flow volume of the fluid on the basis of the propagation time.

Simultaneous reconstruction of flow and temperature cross-sections in gases using acoustic tomography.

Abstract: This paper describes the use of air-coupled ultrasonic tomography for the simultaneous measurement of flow and temperature variations in gases. Air-coupled ultrasonic transducers were used to collect through-transmission data from a heated gas jet. A transducer pair was scanned in two-dimensional sections at an angle to the jet, and travel time and amplitude data recorded along various paths in counter-propagating directions. Parallel-beam tomographic reconstruction techniques allowed images to be formed of variations in either temperature or flow velocity. Results have been obtained using heated jets, where it has been shown that it is possible to separate the two variables successfully.

Flowmeter mounted on a containment

Abstract: Flowmeter comprising at least two ultrasonic transducers that are mounted on a container which is penetrated by a medium in a certain direction of flow. The ultrasonic transducers alternately transmit and receive ultrasonic test signals in the direction of flow and counter to the direction of flow. The flowmeter further comprises a control/evaluation unit which determines and/or monitors the volume flow of the medium inside the container based on the difference in the travel time of the ultrasonic test signals propagating in the direction of flow and counter to the direction of flow. The ultrasonic transducers are configured such that they transmit and receive ultrasonic test signals or sound fields having a large aperture angle or a great beam expansion.