GPMs will utilize Francis-type pump-turbines at ground level which are capable of providing high efficiency at high head (pressure) in both the pump and turbine modes. These same pump-turbines are the core technology behind PSH and are traditionally custom designed using a trial-and-error iterative process that requires several years for development. However, a steadily improving knowledge of hydrodynamics and computational fluid dynamics (CFD), coupled with vastly improved computer capability, allows for a different approach: CFD-based computer-aided design.
|GPM Pump-Turbine Elements|
Pump-turbines can ramp from zero to full power in large GPM installations in under 20 seconds, making their fast response ideal for servicing the Ancillary Services and Peaking Power markets. Their efficiency and ramp rates are much higher than those of gas combustion turbines. Gravity Power is exploring supply and joint venturing arrangements with qualified global companies to supply serial production of Francis pump-turbines for GPMs.
Over the last two decades our Chief Scientist, Dr. Jingchun Wu, has developed a CFD-FEA-based design optimization system that integrates internally developed blade design tools, automatic mesh generators, and parameterized mathematical geometry models, with commercial 3D Navier–Stokes code. This powerful system provides a far more efficient means of optimization than the traditional trial-and-error approach and has been used to design the pump-turbine runner, tandem cascade, spiral casing, and partial draft tube to meet the specific requirements of a GPM.
GPM Pump-Turbine Elements
Pump-Turbine Optimization CFD Grid
Pressure Distribution at Pump-Mode
Pressure on Runner Plus Streamlines