US NAVY DEVELOPMENT OF AIR ASSIST FUEL NOZZLE SYSTEM FOR THE 501K SERIES GAS TURBINE ENGINES

摘要

The U.S. Navy has experienced problems with liquid fuel nozzles used on the Rolls Royce (formerly Allison) 501K series marine gas turbine engines. The 501K engines used by the U.S. Navy power Ship Service Gas Turbine Generators (SSGTGs) on a number of destroyer and cruiser class ships. Over roughly the last 25 years, 3 different nozzle designs have been employed, the latest and current nozzle being a piloted air blast design. The primary failure modes of these designs were internal fuel passage coking and external carbon deposits. The current piloted air blast design has a hard time replacement requirement of 1500 hours. This life is considered unacceptable. To improve fuel nozzle life, the Navy and Turbine Fuel Technologies (formerly Delavan) teamed in a fast track program to develop a new fuel nozzle with a target life of 5000 hours and 500 starts. As a result, an air assist/air blast nozzle was developed and delivered in approximately 6 months. In addition to the nozzle itself, a system was developed to provide assist air to the fuel nozzles to help atomize the fuel for better ignition. Nozzle sets and air assist systems have been delivered and tested at the NSWC Philadelphia LBES (Land Based Engineering Site). In addition, nozzle sets have been installed aboard operating ships for in-service evaluations. During the Phase one evaluation (July 2000 to June 2001) aboard USS Porter (DDG 78) a set of nozzles accumulated over 3500 hours of trouble free operation, indicating the target of 5000 hours is achievable. As of this writing these nozzles have in excess of 5700 hours. The improvements in nozzle life provided by the new fuel nozzle design will result in cost savings through out the life cycle of the GTGS. In fact, the evaluation nozzles are already improving engine operation and reliability even before the nozzles' official fleet introduction. This paper describes the fuel nozzle and air assist system development program and results of OEM, LBES and fleet testing.