M.L. Sanderson

Guidelines for the use of ultrasonic non-invasive metering techniques

Abstract This paper provides a comprehensive set of Guidelines for the application of clamp-on transit time ultrasonic flowmeters to a wide range of industrial flows. These Guidelines have been drawn up in conjunction with users and manufacturers and sponsored by the United Kingdom’s Department of Trade and Industry. They represent the best practice to be used for the application of this technology to liquid metering. The Guidelines identify the range of possible non-invasive technologies which can be employed for the measurement of pipe flows and installation, pipework, fluid and operational effects on clamp-on transit time ultrasonic flowmeters, together with effects which may be specific to particular manufacturers. The paper concludes with the identification of further work which needs to be undertaken to strengthen the Guidelines.

Problems in the theory and design of electromagnetic flowmeters for dielectric liquids: Part 1: experimental assessment of static charge noise levels and signal-to-noise ratios

This paper reports on experimental measurements of electrode signal noise spectra in an electromagnetic flowmeter designed for flow measurement of the dielectric liquid BP180. The design of the flowmeter tube and the detection electronics is described. Dependence of the noise spectra on flow rate, electrode dimensions and particle content of the liquid is reported. Implications for flowmeter tube design and for the choice of frequency of operation to achieve reasonable signal-to-noise ratios are explained.

Problems in the theory and design of electromagnetic flowmeters for dielectric liquids. Part 2b: theory of noise generation by charged particles

Abstract This paper describes an analytical model of the generation of noise by charged particles in electromagnetic flowmeters working with dielectric fluids. Using estimated charge values for the particles, the model predicts that particle noise dominates in the case of dirty liquids, with very small particle concentrations producing high levels of noise. Validation of the theory is done by comparison with available experimental data of noise in BP 180 oil for different flow rates and electrode lengths. The model can be used to study the noise spectrum of a particular meter design when the liquid and particle physical properties are known.

Problems in the theory and design of electromagnetic flowmeters for dielectric liquids. Part 2a: Theory of noise generation by turbulence modulation of the diffuse ionic charge layer near the pipe wall

Abstract This paper describes an analytical model of the generation of noise by turbulence modulation of the background charge distribution in electromagnetic flowmeters working with dielectric liquids. The model is tested for the highly insulating oil BP180 in cases with different flow speeds and electrode lengths, and the results show good agreement with the available experimental data. Comparison of experimental results of filtered and unfiltered oil shows that turbulence modulation of the background charge is responsible for the generation of noise in the filtered case, and that other source of noise is present in the unfiltered case. This model is therefore valid for clean fluids, and can be used to study the characteristics of the noise spectrum of a particular meter design under this condition.

Signal recognition: Fourier transform vs. Hartley transform

Abstract The new generic feature representation approach was utilized for Gaussian recognition. Approach consists of using simultaneously two new recognition features: real and imaginary Fourier components with taking into account the covariance between features. Advanced time–frequency technique, short time Fourier transform was considered. The recognition effectiveness between the new approach and Hartley based approach was compared. It was shown for Gaussian recognition that Hartley approach is not an optimal and is not even a particular case of the proposed approach. The use of the proposed approach provides an essential effectiveness gain in comparison with Hartley approach.

Domestic water metering technology

Abstract This paper is concerned with the design and performance of a novel fluidic oscillator flowmeter which has been developed for domestic water metering applications. The flowmeter employs electromagnetic sensing of the oscillations. The paper discusses the possible locations of the sensor, the magnetic field and electrode structures which can be used, and estimates the signal strengths at the various locations. For the sensor configuration in the main jet it is shown that the signal strength is affected by the shorting caused by the stagnant fluid surrounding the jet, the velocity profile of the jet, and incomplete switching of the jet. It is shown that the sensor provides sufficient signal strength over the range of flows required for a class D Q n 1 domestic water meter ( Q n 1 = 1m 3 h −1 ), for which the range of flows over which an accuracy is specified is from 2 ml s −1 to 0.55 l s −1 .

Signal recognition: fourier transform vs. Cosine transform

A new feature representation approach, the simultaneous usage of the real and imaginary Fourier components with taking into account the covariance between these components, was compared with the Cosine transform approach for Gaussian recognition.

Streaming current noise generation in electromagnetic flowmeters measuring conducting fluids

Abstract This paper provides a model of streaming current noise generated by the interaction of turbulence with the charge distribution which occurs in the liquid, close to the surface of the insulating liner of an electromagnetic flowmeter, as a consequence of charge species being absorbed by the lining material itself. Such noise is present whether the electromagnetic field of the flowmeter is excited or not. It is shown in this paper that this noise can be detected in potable water at a conductivity of order 5 mS/m, although at such levels it is often masked by the first stage amplifier noise, but that it becomes more significant when measurements are made in de-ionised water where the conductivity may be as low as 5 μS/m. The predicted spectral characteristic of the noise and the dependencies of the noise on the conductivity of the fluid, the pipe size and flow velocity provided by the model are all shown to be in good agreement with experimental data. The model is valid for clean aqueous fluids, where there is no noise generated by particle impact or significant electrochemical reaction between the fluid and the sensing electrodes. It can be used to predict the signal to noise ratios in electromagnetic flowmeters using different excitation waveforms and frequencies or different electrode structures.

A Novel Two-Phase Gas\Liquid Slug Flow Measurement System Using a T-Junction Separator and Ultrasonic Measurements

Over the last decade, the development and deployment of in-line multiphase flow metering systems has been a major focus worldwide. Accurate measurement of multiphase flow in the oil and gas industry is difficult because it occurs in wide range of flow regimes and multiphase meters do not generally perform well under the intermittent slug flow conditions which commonly occur in oil production. A novel ultrasonic multiphase metering concept has been proposed and investigated which measures the flow rates of the liquid and gas phases from ultrasonic measurements made in two different flow regimes – partially separated and homogeneous — in the same measurement system and fuses the data from the different flow regimes to obtain improved overall measurement accuracy. The system employs a partial gas/liquid separation using a T-junction configuration and a combination of Doppler and cross correlation. The partially separated flow regimes uses ultrasonic cross correlation measurement for the liquid flow measurement which has gas entrained within it. The homogeneous regime employs ultrasonic Doppler method. This approach has been tested on water/air flows on a 50mm facility in the Department of Process and Systems Engineering. The liquid and gas flowrate measurements using the proposed techniques were compared with a reference measurement and good agreements between these two measurements were obtained with error ranging from ± 2% and 10%, respectively. Such a performance offers the potential for an in-line multiphase flowmeter with improved performance.Copyright

The Engineering Doctorate — An "Enhanced" Doctoral Programme for Engineers Incorporating Business Decision-Making Skills:A Gas Turbine Engineering Perspective

This paper describes a new UK initiative in the post graduate education of Engineers. The new ‘enhanced’ degree of Engineering Doctorate educates graduate Engineers in their respective technical disciplines whilst at the same time integrating the world of commerce and business into the technical decision making process.The paper describes the initial candidate selection methodology, project selection, course structure, assessment, thesis structure and outputs. The advantages of this enhanced postgraduate training are demonstrated, as are the objectives for the UK in adopting such a scheme.An example is presented from a joint Rolls Royce / Cranfield case study of the Design, Development and Product launch of a new type of Gas Turbine Instrumentation. This is set in a Gas Turbine Engineering perspective, in particular the consideration of active control of compressor surge to benefit aircraft engine fuel burn and increased flight range.Copyright