About AQFlow

AQFlow's mission is to produce acoustic scintillation flow measurement systems that will be globally recognized as the solution to the hydro-electric industry's toughest discharge measurement challenge: turbine flow measurement in short converging intakes of low-head plans.

ASL Environmental Sciences has over 30 years of experience carrying out successful flow velocity measurement programs in the most difficult ocean environments from the Arctic to the tropics. The company has been working in hydroelectric applications for over 20 years, since 2000 through AQFlow.

Early projects related to the hydroelectric industry include:

• Flow surveys in forebays and tailraces of hydro plants in Canada and the USA since the 1980s.
• In 1990/91, flow measurements in the forebay of the Rocky Reach Dam for Chelan P.U.D.
• In 1992, a prototype of the Acoustic Scintillation Flow Meter (ASFM) at Rocky Reach.
• Flow studies at Fort Patrick Henry and Wheeler Dams, Tennessee Valley Authority, in 1997 and 1999.
• The first ASFM system was sold to the US Army Corps of Engineers (USACE), Portland District in 1998. Between 1998 and 2001, measurements with this system were conducted successfully at McNary, Bonneville, Lower Granite and The Dalles.

3-bay, 10-path ASFM Advantage System

In 2001, ASFM Advantage was released. It incorporated significant refinements, and has since been used successfully and effectively by:

• Nova Scotia Power - Canada
• Hydro Kennebec - USA
• US Army Corps of Engineers - USA
• Edison Sault Electric Company -USA
• Portland General Electric - USA
• Hydro Quebec - Canada
• Korea Water Resources Corp.
• Douglas County PUD - USA
• Electricite de France

In 2005, ASFM Monitor was introduced. This non-intrusive system can be installed permanently in the intake and provide continuous, repeatable and reliable real-time monitoring of turbine discharge.

Typical Applications of the ASFM include:

• Measuring absolute turbine discharge
• Measuring turbine discharge to check measurements obtained with other technologies
• Measuring turbine discharge to calibrate Winter-Kennedy readings
• Measuring the effect of fish diversion screens on turbine efficiency
  

Future Applications

AQFlow continues to pursue research into other challenging hydro applications needing innovative flow measurement techniques, including spillways.

Code Acceptance

The process of obtaining code recognition continues. It is expected that code acceptance will be attained by the end of this decade. The international committees responsible for the ASME PTC-18 Hydraulic turbine and pump turbines and the IEC 41 Test code for field acceptance tests to determine the performance of hydraulic turbines are currently considering the inclusion of the acoustic scintillation technology in the next issue of their respective codes.

CFD Modeling

Computational Fluid Dynamics (CFD) modeling has been used by the industry to optimize hydro turbine designs for many years. CFD has now become an indispensable tool in the design of entire hydro installations, from intakes to draft tubes, and from forebays to tailraces.

AQFlow has applied the CFD technique since 1998, using a cluster of computers and sophisticated CFD software including the latest ANSYS and Amtec products (CFX, Fluent, ICEMCFD). By conducting direct field measurements of velocity and turbulence in combination with the CFD modeling, AQFlow has gained better understanding of the complex fluid physics in the converging intakes of the low head plants. In turn, this helped us to make better measurements with the ASFM.