ASME Low Head Investigation
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Flowrate Measuement

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ASME Low Head Investigation

A need exists in the hydro-electric community to find ways to more accurately measure flow in short, convergent intakes typical of low-head hydropower sites. Experts in the hydro electric industry predict that, by reducing flow uncertainty by just 1 percent at such sites, the North American hydro industry could save $136 million a year. (This calculation assumes 60 percent of hydropower generating units with short, convergent intakes; an energy value of US$40/MWh; average annual Canadian hydropower production of 310,000,000 MWh; and average annual U.S. production of 255,000,000 MWh.)


ASME’s Performance Test Code (PTC) Committee No. 18 on Hydraulic Prime Movers is investigating this issue and to possibly include measurement methods in the next revision of ASME PTC 18, Hydraulic Turbines and Pump-Turbines. Currently, neither the ASME test code nor the International Electrotechnical Commission test code (IEC 60041) deal specifically with the application of flow measurement methods for short, convergent intakes. ASME Committee members hope to revise the current published code PTC 18-2002 so that it includes a code-approved and contractually agreeable method or methods for testing in plants with short, convergent intakes. In addition, hydro project owners would be able to determine absolute performance curves for units in these plants.  Currently, some performance testing has occured at various low head intake plants such as Wells Hydro in Chelan Washington. >Read more  Other testing with ultrasonic flowmeters has taken place as early as 1993 at Safe Harbor in Pennsylvania. >Read more


To support these efforts, ASME PTC-18 Committee members are also coordinating a series of comparative field tests to assess the applicability of a variety of test methods, including acoustic time of flight, current meters, and acoustic scintillation, for accurately measuring flow in short, convergent intakes.