Gas Turbine - How Gas Turbine Fuel Nozzle works

Gas turbines typically have multiple fuel nozzles through which fuel is injected into the combustion zone. Ideally the fuel flow rate through each nozzle should be uniform and the mixing of fuel with air should be equally effective for each nozzle. If liquid fuel is being injected, the atomization of the fuel droplets should also be identical for each nozzle. If maldistributions occur, the result will be uneven firing temperatures around the circumference of the combustion section. Since most gas turbines do not have thermocouples at the exit of the combustors, these uneven firing temperatures are typically detected by thermocouples mounted further downstream. Single-shaft gas turbines have an array of thermocouples installed around the circumference of the outlet of the turbine, while multiple-shaft turbines typically have a thermocouple array around the inlet of the power turbine. Almost all gas turbine control systems monitor “exhaust temperature spread” and issue an alarm when this reaches an OEM-specified value. The challenge for the turbine O&M staff is then to figure out the source of the high temperature spread. A gas turbine fuel nozzle injects a liquid fuel flow from a liquid fuel passage in the swirler vane. An air flow over the swirler vane atomizes the liquid fuel flow to form a fuel air mixture. The fuel nozzle eliminates the need for a conventional air blast atomizer. There is DM water flow passage for Reducing the NOx and Natural gas passage is on the outer side. base load and peak load power plants.