General Design Requirements

The inlet system should be designed for at least 220 pounds per second combustion airflow plus package ventilation airflow. Ducts should be as short and straight as the installation will permit; the number of bends and contractions should be kept to a minimum. Projections inside the inlet ducting (such as pipes, wiring, ladders, etc.) should be avoided if possible.

Materials and finishes should be chosen to ensure that corrosion or deterioration will not result in release of particles that could cause foreign-object damage to the gas generator/gas turbine. Zinc plating (galvanizing) shall not be used to protect the intake structure exposed to the engine inlet air.

All fasteners (nuts, bolts, rivets, etc.) in, or having the potential for entry into the inlet airflow path, must be positively retained to preclude loosening and possible entry into the inlet. A four-mesh screen mounted on the inlet partition wall immediately in front of the inlet bellmouth is strongly recommended to reduce the potential for foreign-object damage. If the Purchaser prefers to operate without permanent inlet screens, it is strongly recommended that a screen be used at least for the initial sweeper operation of the installation.

A flange is provided on the inlet bellmouth for installation of a flexible seal between the bellmouth and partition wall between the inlet plenum and the remainder of the unit. The seal must place no more than 100 pounds of axial load, no bending, and no shear load on the bellmouth.

A gas turbine bellmouth seal assemby is available to the Purchaser as optional equipment.

The design of the inlet plenum should include provisions for floor drainage of effluent from compressor crank-soak, fired wash cleaning, rain water ingestion, and inadvertent fluid spills. All drain lines should incorporate a U-tube water trap and siphon breaker to prevent back-siphoning or suction of foreign material, debris, or fluids into the plenum during engine operation with the inlet filters at the pressure drop limit.

In the event of a compressor stall or surge in the engine, a pressure wave will be generated. The resulting pressure is a function of the inlet plenum size and arrangement; for typical inlet plenums, it will normally not exceed 3 psig for 5 milliseconds maximum at the face of the engine bellmouth and will dissipate as a function of distance from the face of the bellmouth.

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19/11/2005http://inside-aep.ps.ge.com/insideaep/aep/iad/engine_prod_delv/idms/lm2500/05general.h...