Successful laboratory tests on a small scale turbine model have shown a project to rehabilitate Center Hill hydrpower project in Tennessee, US, is on track, the US Army Corps of Engineers has announced.

The Corps Nashville District awarded a $47.25 million contract to Voith Hydro in June 2014, to rehabilitate three Center Hill Dam hydropower units. Voith designed the turbine, built a to-scale turbine model in York, Pennsylvania, and then operated it to ensure it meets design specifications.

Voith Hydro technicians put the model through its paces from 6-9 October, while representatives from the Hydroelectric Design Center in Portland, Oregon, verified the results.

Ryan Sollars, mechanical engineer with HDC, said Voith Hydro provided the Corps a model test report several weeks ago. He previewed the report and then witnessed and verified the data points provided.

Sollars said he looked closely at efficiencies, cavitation, dimensional tolerances, draft tube pressure pulsations, runaway speed of the runner, wicket gate torque, and even the validity of the checks being conducted.

"The goal is to verify you are not going to have any issues with these units, and they generally last for many years… 40, 50, 60 years. So it’s important that you get high efficiency," Sollars explained. "We witnessed checks through the entire operating range, and found that Voith has exceeded the contract requirements."

The Nashville District also sent a small team of experts to the lab on 8 October, to receive a briefing, ask questions and witness the operation of the model turbine.

During the witness test, Nashville District personnel stood underneath the turbine and watched it operate through Plexiglas. The lab technicians applied different operating conditions to demonstrate the turbine’s efficient operation.
Francisco Kuljevan, hydraulic engineer with Voith Hydro, said the model testing conducted at S. Morgan Smith Memorial Laboratory, measured the performance of the turbine to ensure it meets the required specifications before the manufacturing process and work to modernize the power house begins. The witness test also provided Voith an opportunity to showcase the turbine and demonstrate that it meets or exceeds the Corps’ requirements.

The rehab of the three turbine generators located at Center Hill Dam is the start of a 20-year process to rehab all of the turbines, and the laboratory testing is vital to the success of the project.

Image: Jeff Linkinhoker (Right), project manager of the U.S. Army Corps of Engineers Nashville District’s Center Hill Hydropower Rehabilitation Project, and Mike Murphy, mechanical engineer with the Hydropower Branch, tour Voith Hydro’s laboratory.

News story by Lee Roberts, Public Affairs Specialist, US Army Corps of Engineers