Laser Doppler Anemometry-Explained!

"There are many types of instrumentation available to today's engineers for the measurement of airflow within a building, but the majority of them are intrusive and this often affects the end result," reports Alan Gilbert, Project Manager at BSRIA.

Using Laser Doppler Anemometry (LDA) involves a non-intrusive method of measuring air velocity. It uses two laser lines that are projected into an air stream containing non-toxic particles that, once detected, allow calculation of the air velocity to a degree of accuracy not seen before. Such a high degree of accuracy in air velocity calibration and airflow instrumentation means BSRIA can offer its clients a greater range of products and services whilst improving turnover and ultimately profit for the organisation.

To date, a special technique has been developed, using the LDA system, to measure the flow rate produced by one of the calibration facilities that is repeatable over a range of air flow rates. UKAS accreditation for this test facility is currently being sought so the company can apply the same technique to other calibration rigs across BSRIA.

"The KTP project is a fantastic opportunity for BSRIA to investigate and apply modern technology that is not widely used in industry. Access to the resources and expertise at LSBU has meant a significant increase in the understanding of the LDA process. This can now be applied to other areas, opening up further business opportunities," comments Alex Mayes, KTP Associate.

LSBU academics Professor John Missenden and Dr Steven Mitchell are providing the expertise. "This project represents an important opportunity to apply research techniques to solve real problems in industry. It is extremely useful to see how academic theories of fluid mechanics, the use of instrumentation and advanced numerical modelling techniques can be applied to the work of BSRIA and make a real difference to their business," says Steve.