Bibb & Associates of Kenexa, KS is the EPC contractor for Tenaska's 890MW combined cycle power plant in Fluvanna County, Virginia.

The Fluvanna Generating Station is a dual fuel plant capable of burning both natural gas and No. 2 fuel oil in its three GE gas turbines and Deltak heat recovery steam generator with duct burner. 410MW of the total generating capacity is provided by a GE condensing steam turbine. Cooling for the main condenser and auxiliary heat exchangers is provided by a system including three, 138,000 gpm main circulating pumps supplying cooling water through 78" diameter supply and return lines in conjunction with a 14 cell cooling tower.

Bibb & Associates enlisted AFT's expertise to model the cooling system and analyze its behavior under a variety of pump shutdown and startup scenarios along with associated main discharge valves opening/closing. AFT Impulse 3.0 was used to model the system and included modeling four quadrant pump hydraulics and inertia effects along with the several vacuum breaker/air release valves in the system and partially filled pipes near the pumps at start up. The completed model consisted of 112 pipes plus the 34,140 tubes in the main condenser. A total of nine cases were analyzed with the results clearly illustrating transient liquid flows, air flow through the vacuum breaker/air release valves and, or course, transient pressures.

Fluvanna Generating Station will depend on its main cooling system for reliable operation. Modeling the system with AFT Impulse allows it designers to insure in the design stage this critical system will meet that requirement.