الفهرس 
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Abstract
The performance of a gas turbine is negatively influenced when operated in hot weather conditions. Inlet air fog cooling is one of the most cost-effective techniques to improve gas turbine performance. The water is atomized into very fine droplets during fog cooling and injected into the inlet airflow. In addition to cooling the inlet air, an over-spray will further increase the output power due to cooling inside the compressor. There is a certain limit for over spray to avoid the damage to the compressor blades. The two-phase flow during the wet compression process still needs more research and development either experimentally or by developing prediction models.
The aim of this research is to study the performance of Siemens (V94.3A2) gas turbine unit equipped with a fogger to cool the air before entering the compressor. The recorded data for this analysis were collected from El korymat, BeniSuef gas turbine unit. The performance of the unit was determined under different compressor inlet temperatures for both on-off conditions of the fogger.
At first, the cooling degree hours were calculated for the site of the gas turbine unit. It gives an idea about the potential of using a fogger cooling process in this region. The results showed that the gas turbine can operate for 13 hours in case of base temperature 20 °C with 7848-degree hours in July. Through the recorded values, the results of the analysis showed that operating the fogger during the peak hours of high temperature in summer gives a power of 16 megawatts higher than that without operating the fogger. On the other side the electrical efficiency increased by 3 % due to the existence of the fogger cooler. When the fogger is turned on at air temperature of 38 °C, the specific fuel consumption decreases by 1.2%. When the compressor inlet temperature drops from 30 °C to 20 °C, the exit temperature from the compressor decreases from 437 °C to 417 °C, i.e., 4.6%. Therefore, cooling the air before entering the compressor is a solution to enhance the performance of the turbine during summer hot days.
Injecting more water droplets than that required for saturation, known as over spray improves the isentropic efficiency of the compressor due to the internal cooling. The results showed that an overspray of 0.0075 kgw/ kga gives an increase of 1.9% in electrical efficiency. In the case of 0.0078 kgw/ kga overspray, the isentropic efficiency of the compressor increased by 2.5% and the electric power increased by 6.6%.
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