Development of a New Fundamental Measuring Technique for the Accurate Measurement of Gas Flowrates by Means of Laser Doppler Anemometry

Dopheide, D.; Taux, G.; Krey, E.A.

doi:10.1088/0026-1394/27/2/004

Cited by 9 publications

(7 citation statements)

References 5 publications

(2 reference statements)

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“…The uncertainty of measurement also depends decisively on the accuracy with which the Doppler bursts can be measured. In 1984, the authors presented a procedure [14] by which LDA signals can be measured with a relative uncertainty of 2 x using the transient recorder technique, a prerequisite being that the signal-to-noise ratio is about 20 dB. An online computer-controlled apparatus allows the uncertainty of measurement of the electronic signal processing chain to be determined routinely when noisy LDA signals are processed with a signal simulator [14].…”

Section: Miniaturized Diode Laser Ldamentioning

confidence: 99%

Three-component Laser Doppler Anemometer for Gas Flowrate Measurements up to 5 500 m³/h

1994

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In the Physikalisch-Technische Bundesanstalt (PTB) the primary standard for on-line flowrate measurements using the laser Doppler anemometer (LDA) technique has been extended to a three-component LDA to improve velocity profile measurements in the boundary layers of a nozzle flow. The LDA flowrate measuring facility now consists of a two-colour argon ion LDA and a wavelength-stabilized GaAlAs diode laser LDA. The gas flowrate is obtained by numerical integration of the measured velocity profiles across the exit plane of the nozzle. High local resolution of the velocity profile measurements is achieved by perpendicular orientation of the measurement volumes of the two-component gas laser LDA and the semiconductor diode laser LDA (LD-LDA). This allows the resolution in the boundary layer to be improved significantly to velocity gradients. The present work presents the LD-LDA system for precise velocity profile measurements at flow velocities of up to 120 m/s; selected profile measurements are described in detail to demonstrate the high resolution and the symmetry of the flow profile. For the first time a wavelength-stabilized miniaturized diode laser LDA has been successfully applied in precise velocity measurements, and comparisons with well-established gas laser LDAs have been made. The uncertainty of the flowrate measurement up to 5 500 m3/h is 0,l YO for air at atmospheric pressure. A turbine gas meter, type Elster G2500, was calibrated with the LDA and used as a transfer standard for an intercomparison with the Nederlands Meetinstituut (NMI) in the flowrate range up to 5 500 m3/h with and without the installation of perforated plates to condition the flow in the inlet section of the gas meter. The results of the comparison experiment clearly show the reliability and accuracy of the online flowrate measurement of gases and underline the necessity for a detailed research programme to investigate the relationship between installation effects, upstream flow conditions and the measurement uncertainty of gas meters. The design of a test rig now under construction at the PTB is shown. This will allow the diode laser LDA technique to be applied to the measurement of installation effects according to OIML Recommendation R-32.

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Section: Miniaturized Diode Laser Ldamentioning

confidence: 99%

Three-component Laser Doppler Anemometer for Gas Flowrate Measurements up to 5 500 m³/h

1994

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“…Laserbased techniques for the measurement of flow rates have several advantages, such as remote, nonintrusive, in situ, spatial, and temporally precise measurement [6][7][8][9]. Laser Doppler velocimetry (LDV) uses the Doppler shift in a laser beam to measure the velocity of particle seeded fluid flows [10,11]. Particle image velocimetry (PIV) measures the flow velocity field by capturing two images of seeding particles in the fluid with a time gap.…”

Section: Introductionmentioning

confidence: 99%

Practical methodology for in situ measurement of micro flow rates using laser diode absorption sensors

et al. 2019

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A laser diodebased flowmeter based on the infrared absorption method that can measure in situ micro flow rates from 0.2 to 20 ml h −1 was developed. A 1450 nm laser absorbed in water was irradiated to form a heated spot at 0 mm, and the temperature was measured upstream and downstream of the heated spot. The flow rate was measured by the temperature difference obtained by two diode lasers and photodetectors upstream and downstream of the heated spot. We measured the temperature profile of the flow rate by changing the temperature measurement position and the heating laser energy upstream and downstream of the heated spot, and compared the measurements with the simulation results. As the flow rate increased, the temperature profile shifted downstream, and the measured temperature upstream and downstream were analyzed according to the flow rate. The flow measurement range was adjusted according to the temperature measurement position. Increasing the energy of the heating laser also improved the measurement accuracy in the lower flow range. The developed flowmeter was calibrated by the gravimetric method, and the deviation and measurement uncertainty according to the flow rate were obtained. The maximum measurement uncertainty was 6.8% at a 1 ml h −1 flow rate, and the minimum measurement uncertainty was 1.78% at 8 ml h −1 . Thus, it was confirmed that the flow rate can be measured through the temperature difference gauged using a simple diode laser set. Using the laser diodebased flowmeter developed in this study, one can measure the flow rate in situ without injecting contaminants, such as particles, for measurements without cutting the piping. In addition, it can be manufactured in a miniaturized form at a low cost, and thus, it can be used for multidrug infusion analysis, semiconductor process monitoring, etc.

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“…The use of nonintrusive technologies for the measurement of fluid velocity was another key point for the final concept of an opticalbased primary flow rate standard. The first prototype of this technology was established by Dopheide [1] in 1990 for air under atmospheric conditions. We want to introduce the realization of a similar approach for high-pressure natural gas (up to 5.5 MPa) and to discuss finally the uncertainties achievable with the technology presented.…”

Section: Introductionmentioning

confidence: 99%

“…The main intention of this paper is to give an overview of the uncertainty budget; hence, we will give detailed explanations of the sources of uncertainty according to equation ( 1) and the determination of their values. This is done separately for the core flow part (c centre and U c ; section 3) and the boundary layer (discharge coefficient c D ; section 4) 1 . Before this, however, we want to introduce details of the technology concept and would like to give a technical description of the facility in section 2.…”

Section: Introductionmentioning

confidence: 99%

A primary standard for the volume flow rate of natural gas under high pressure based on laser Doppler velocimetry

Mickan

Strunck

2014

Metrologia

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In December 2003, the Physikalisch-Technische Bundesanstalt (PTB) started the development of an optical-based primary flow rate standard for application in natural gas under high pressures (up to 5.5 MPa). The concept underlying this technology will be presented in this paper. The technical approach is based on the application of a conventional laser Doppler velocimeter (LDV) as well as on a new LDV-based boundary layer sensor. Both technologies are used to determine the characteristic values of the core flow and the boundary layer in a nozzle flow in a separated approach. Because of the high relevance to the demonstration of traceability and to the evaluation of the uncertainty, the related data processing (especially for the boundary layer) is explained in detail. Finally, after summarizing the uncertainty budget for the optical-based primary standard, we will demonstrate the approval of the new primary standard by means of a comparison with the established conventional traceability of PTB for high-pressure natural gas.

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Development of a New Fundamental Measuring Technique for the Accurate Measurement of Gas Flowrates by Means of Laser Doppler Anemometry

Cited by 9 publications

References 5 publications

Three-component Laser Doppler Anemometer for Gas Flowrate Measurements up to 5 500 m³/h

Three-component Laser Doppler Anemometer for Gas Flowrate Measurements up to 5 500 m³/h

Practical methodology for in situ measurement of micro flow rates using laser diode absorption sensors

A primary standard for the volume flow rate of natural gas under high pressure based on laser Doppler velocimetry

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Development of a New Fundamental Measuring Technique for the Accurate Measurement of Gas Flowrates by Means of Laser Doppler Anemometry

Cited by 9 publications

References 5 publications

Three-component Laser Doppler Anemometer for Gas Flowrate Measurements up to 5 500 m3/h

Three-component Laser Doppler Anemometer for Gas Flowrate Measurements up to 5 500 m3/h

Practical methodology for in situ measurement of micro flow rates using laser diode absorption sensors

A primary standard for the volume flow rate of natural gas under high pressure based on laser Doppler velocimetry

Contact Info

Product

Resources

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Three-component Laser Doppler Anemometer for Gas Flowrate Measurements up to 5 500 m³/h

Three-component Laser Doppler Anemometer for Gas Flowrate Measurements up to 5 500 m³/h