Fog Cooling, Wet Compression and Droplet Dynamics In Gas Turbine Compressors

During hot days, gas turbine power output deteriorates significantly. Among various means to augment gas turbine output, inlet air fog cooling is considered as the simplest and most costeffective method. During fog cooling, water is atomized to micro-scaled droplets and introduced into the inlet airflow. In addition to cooling the inlet air, overspray can further enhance output power by intercooling the compressor. However, there are concerns that the water droplets might damage the compressor blades and increased mass might cause potential compressor operation instability due to reduced safety margin. Furthermore, the two-phase flow thermodynamics during wet compression in a rotating system has not been fully established, so continued research and development in wet compression theory and prediction model are required. The objective of this research is to improve existing wet compression theory and associated models to accurately predict the compressor and the entire gas turbine system performance for the application of gas turbine inlet fog cooling. The following achievements have been accomplished: (a) At the system level, a global gas turbine inlet fog cooling theory and algorithm have been developed and a system performance code, FogGT, has been written according to the developed theory. (b) At the component level, a stage-stacking wet compression theory in the compressor has been developed with known airfoil configurations. (c) Both equilibrium and non-equilibrium water droplet thermal-fluid dynamic models have been developed including droplet drag forces, evaporation rate, breakup and coalescence. A liquid erosion model has also been developed and incorporated. (d) Model for using computational fluid dynamics (CFD) code has been developed to simulate multiphase wet compression in the rotating compressor stage. In addition, with the continued increase in volatility of natural gas prices as well as concerns regarding national energy security, this research has also investigated employing inlet fogging to gas turbine system fired with alternative fuels such as low calorific value synthetic gases. The key results include discovering that the saturated fogging can reduce compressor power consumption, but overspray, against conventional intuition, actually increases compressor power. Nevertheless, inlet fogging does increase overall net power output.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Year

2009

Author dc:creator

• Khan, Jobaidur Rahman

Contributors dc:contributor

• Wang, Ting
• Akyuzlu, Kazim
• Guillot, Martin

• Wet compression
• Overspray
• Axial Compressor

Repository record dc:identifier

https://scholarworks.uno.edu/td/908

OAI identifier oai:identifier

oai:scholarworks.uno.edu:td-1889