1 Copyright © 2002 by ASME Proceedings of ASME Turbo Expo 2002 June 3-6, 2002 Amsterdam, The Netherlands 2002-GT-30563 INLET FOGGING OF GAS TURBINE ENGINES - PART B: FOG DROPLET SIZING ANALYSIS, NOZZLE TYPES, MEASUREMENT AND TESTING Mustapha Chaker, Ph. D. Director, Research and Development Cyrus B. Meher-Homji Chief Engineer Thomas Mee III, Chairman and CEO Mee Industries Inc., Gas Turbine Division Monrovia, California, USA ABSTRACT The inlet fogging of gas turbine engines for power augmentation has seen increasing application over the past decade yet not a single technical paper treating the physics and engineering of the fogging process, droplet size measurement, droplet kinetics, or the duct behavior of droplets, from a gas turbine perspective, is available. This paper provides the results of extensive experimental and theoretical studies conducted over several years, coupled with practical aspects learned in the implementation of nearly 500 inlet fogging systems on gas turbines ranging in power from 5 to 250 MW. Part B of the paper treats the practical aspects of fog nozzle droplet sizing, measurement and testing presenting the information from a gas turbine fogging perspective. This paper describes the different measurement techniques available, covers design aspects of nozzles, provides experimental data on different nozzles and provides recommendations for a standardized nozzle testing method for gas turbine inlet air fogging. NOMENCLATURE A d Surface Area of the Droplet (m 2 ) AD or D21 Absorption Diameter (m) AMD or D10 Arithmetic Mean diameter (m) ASTM American Society for Testing and Materials CV Concentration Volume (ppm) D d Droplet Diameter (m) ED or D31 Evaporative Diameter (m) Fpm Feet per Minute MMD or Dv50 Mass Median Diameter (m) PDPA Phase Doppler Particle Analyzer PMS Particle Measurement system RSF Relative Span Factor SAMD Surface Area Mean Diameter (m) SMD or D32 Sauter Mean Diameter (m) V d Droplet Volume (m 3 ) VMD or D30 Volume Mean Diameter (m) V rel Droplet relative velocity (m.s -1 ) We Weber Number γ w Surface tension of the water (N.m -1 ) ρ a Density of the air (kg.m -3 ) INTRODUCTION Over the past decade and especially over the past five years, the application of inlet fogging for the power augmentation of gas turbines has become increasingly popular. It is estimated that approximately 700 gas turbines worldwide have fogging systems at this time including several new F-class gas turbines. To this point however, not a single technical paper exists comprehensively covering the physics and engineering of the fogging process, droplet measurement, kinetics, duct behavior of droplets from a gas turbine perspective. This paper provides the results of extensive experimental and theoretical studies conducted over several years, and also mentions practical aspects learned in the implementation of nearly 500 inlet fogging systems on gas turbines. A major problem faced by gas turbine users considering the utilization of inlet fogging is that different fog nozzle manufacturers and suppliers present data in very different formats and under different operating conditions. In this paper we point out the key operating parameters that are pivotal in a gas turbine fogging application and also provide data on a large number of nozzle tests made in our experimental wind tunnel.