Key Parameters for the Performance of Impaction-Pin Nozzles Used in Inlet Fogging of Gas Turbine Engines

Abstract

Application of inlet air fogging to gas turbine engines for power augmentation, has become common practice, with more than a 1000 installations worldwide including a large number of advanced gas turbines. In this paper an experimental investigation and empirical analysis of key operating parameters on the performance of impaction pin nozzles will be investigated. To this date no such correlation is available for impaction pin nozzles, which are currently used in about 75% of this type of applications. The correlations are developed from a series of experiments conducted in a wind tunnel equipped with the Malvern Spraytec droplet size measurement system. The conducted analysis covered a wide range of the relevant parameters. Mainly the water flow rate from the nozzle orifice was (0.00126 1.s−1 to 0.00063 1.s−1: 0.02 gpm to 0.1 gpm), the operating pressure was (34.5 bars to 204.1 bars: 500 psi to 3000 psi), the airflow velocity was (1.5 m.s−1 to 15.2 m.s−1: 295 fpm to 3000 fpm), the distance between the nozzle orifice and the location of measurement was (0.0127m to 0.508 m: 0.5” to 20”). Other parameters such as the plume spray one angle and the surrounding ambient psychrometric conditions, which may affect the droplet size for impaction pin nozzles is also discussed.