Design and Method for the Evaluation of the Coking Resistance of Swirl Plates of the E-2C Aircraft Fuel Nozzles

The extensive coking observed on the swirl plates of the fuel nozzles of the E-2C HAWKEYE aircraft is the initiative of this investigation. A testing rig reproducing the shut down procedure of the engine was designed and a method for the evaluation of the resistance in coking for different types of swirl plates is presented. The method is based on measurements of weight increase and holes closure, and on microscopic examination. It can be applied to the evaluation of any suggested modification of swirl plates in the future and provides the NAVY with a reliable easy to use and modify experimental set-up able to produce comparative data. Results for two different types of swirl plates with different surface finish are presented, together with conclusions and comments arising from the experimental results and the design process. Recommendations for future search objectives to the problem are also presented