Flow Measurement Technologies

The need to act on climate change, and sustainable energy security, is well documented. The Climate Change Act 2008 committed the UK to reduce the net carbon account for 2050 by at least 80% of the 1990 baseline. In June 2019, the Climate Change Act 2008 (2050 Target Amendment) Order 2019, set a target for at least a 100% reduction. Based on an earlier Committee on Climate Change (CCC) assessment, the net-zero target is beyond current technical feasibility: only further research and development, innovation and technology development will deliver the target.

However, the development of low carbon technologies alone is insufficient. In summary - “you cannot control what you cannot measure”. The pursuit of net-zero requires the development of measurement technology and infrastructure for accurate tracking of key materials (for example, carbon dioxide and hydrogen) economy-wide, which are not currently available. These measurement systems are necessary in order to evaluate the effectiveness of particular low carbon technologies or policies, and for formal reporting or auditing.

Coventry University has joined TÜV SÜD and other partners to form the Clean Fuels Centre, with the aim of developing flow measurement validation technologies and infrastructure to support the roll-out of net-zero energy systems.

Group members have been at the forefront of developing new flow metering technologies, from first concept through to final commercial product, for over 20 years. There is particular expertise in the technique known as Coriolis mass flow metering, which is widely used throughout the energy, pharmaceutical, chemical and food and beverage industries.

While Coriolis meters are known to be accurate when measuring either pure liquids or pure gases, for example measuring to within ± 0.1% for liquids, in the past poor accuracy is achieved when measuring mixtures of liquid and gas. This is of practical importance in many applications, for example in oil and gas, or chemical applications. The group’s novel use of digital electronics, advanced signal processing, and neural networks has enabled the development of new Coriolis meters which have successfully been used in operations ranging from oils fields to ship refuelling. Activities range from the demonstration of first principles using prototype devices through to developing commercial products with flow meter manufacturers as partners.

Currently, there is focus of developing fast flow measurement, for example measuring the stream of 1 millisecond fuel injection pulses in an internal combustion engine; developing optimising Coriolis meters for working with hydrogen, for example at filling stations for ‘green’ vehicles; and improved operation in multiphase flow mixtures, from oil and gas to carbon dioxide in carbon capture and storage applications.

Improvements in signal processing is one of the chief means of providing enhanced flow meter performance, whether by improving measurement accuracy, or by extending the operating range of meters into more difficult applications such as dealing with gas/liquid mixtures.

Prism Signal Processing is a new technique, developed within the group, which addresses many of the challenges for instrumentation arising from the Internet of Things and Industry 4.0. The Prism is a recursive finite impulse response (FIR) filter, offering linear phase response and numerical stability. Unlike conventional FIR filters, the computation of the Prism is fully recursive, so that the computational cost is independent of the length of the filter.

A further benefit of the Prism is that filter design is very simple, so that new signal processing structures can be created in real time within resource-limited devices as signal properties and/or processing requirements change.

A range of signal processing techniques have been developed based on the Prism, such as static and dynamic notch filters, band-pass filters, and trackers, which extract the frequency, phase and/or amplitude of a sinusoidal component within the supplied signal. These tools share the Prism's characteristic rapid calculation and easy design.
Prism techniques have been applied to a variety of applications. In the case of Coriolis mass flow metering it has been possible to achieve 100x faster measurement updates, providing tracking, for the first time, of the mass flow rate of engine fuel injection pulses as short as 1ms.

The techniques can be used in devices ranging from low cost processors or FPGAs up to supercomputers, to isolate and track one or more signal components. While the first applications of Prism Signal Processing have been in flow metering, it is likely to offer advantages in other measurement and control domains, and we welcome enquiries from potential partners who would be interesting in collaboration.