Fish Strike Survival
In 2019, Natel performed controlled laboratory strike tests at Alden Laboratory to understand the effect of the uniquely thick, curved leading edge of the RHT on fish survival. The scientific findings are published in the Journal of Ecohydraulics and are guiding Natel's fish-safe turbine design process.
The results of this study indicate that the RHT can safely pass juvenile salmonids (up to 300 mm in length) with >99% success rate through the turbine in its operating range, while larger fish are effectively screened by low-maintenance standard trash racks at the intake.
Further fish testing, including field demonstration of fish survival, is underway.
Test of Rainbow Trout Passage through the RHT
Test of American Eel Passage through the RHT
Test of Juvenile Alewife Passage through the RHT
Fish Safe Restoration Hydro Turbine Video
Monroe Fish Passage Testing Video
Hydraulic Performance Testing
Natel's hydraulic performance testing facility is located onsite at the Alameda headquarters and enables scale model turbine testing at net heads up to 10 meters and flow rates up to 1 cms. The test stand utilizes world-class instrumentation for measurement of flow, pressure, torque, and speed to achieve PTC standard compatibility.
In June 2019, a D55 (0.55m diameter runner) RHT prototype unit was tested by Jim Walsh of Rennasonic Inc., chair of IEC TC-4 and PTC-18. Key results from the test are summarized below. The full report is available by request.
- Peak hydraulic efficiency >90.5%
- Experimental uncertainty <0.5%
- Good correlation to CFD simulation results