Cooling Circuit for Enhancing Turbine Performance

Abstract

In a gas turbine having a compressor discharge casing, a cooling circuit diverts compressor discharge air toward a high pressure packing (HPP) circuit. The cooling circuit includes an inlet pipe that receives compressor discharge air. One or several cooled cooling air pipes are in fluid communication with the inlet pipe via a pipe manifold, which distributes the discharge air across the cooled cooling air pipes. A seal is disposed upstream of an entrance to the HPP circuit to limit flow into the HPP circuit, and a second seal is disposed downstream of the HPP circuit at turbine wheelspace to limit ingestion and thus the purge flow air required. The circuit serves to reduce required purge flow in the HPP circuit so that an amount of compressor discharge air can be put back to the main flow path, thereby improving turbine performance.

Description

BACKGROUND OF THE INVENTION[0001]The invention relates to a structure and method for enhancing turbine performance and, more particularly, to a cooling circuit that diverts compressor discharge air to supplement the total required purge flow and cool critical turbine components.[0002]The compressor discharge air leaking past the high pressure packing (HPP) of a gas turbine is typically returned to the primary gas path via the first forward wheelspace, between the first stage nozzles and first stage buckets. This secondary flow path is referred to as the HPP circuit. This air is used for two purposes: (1) it is used as purge flow in the first wheelspace to prevent hot gas ingestion; and (2) it cools critical components in the HPP circuit. Some of the critical components in the HPP circuit include the compressor tie bolts, marriage joint, nozzle support ring and first stage wheel.[0003]In some designs, the flow level in the HPP circuit is higher than the wheelspace purge requirement b...

AI Technical Summary

Benefits of technology

"The patent describes a cooling circuit for a gas turbine that improves turbine performance by increasing flow in a high pressure packing circuit. The cooling circuit includes an inlet pipe, cooled cooling air pipes, a pipe manifold, and valve to adjust mass flow and temperature. The circuit also includes upstream and downstream seals to regulate air entering and exiting the circuit. The technical effect of the cooling circuit is to increase the mass flow of air in the high pressure packing circuit, which improves turbine performance."

Problems solved by technology

The cooled cooling air is not adjustable.

No cooled cooling air is needed there, however, because of lower compressor discharge temperatures and consequently lower temperatures in the HPP circuit resulting in adequate wheelspace temperature margins.

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