|
|
   
|
Active Combustion Control
The three main areas of interest in the active control of aircraft engine combustion systems are: combustion instability control, emission minimizing control and pattern factor control. Combustion Instability ControlAs the requirements for reducing emissions become more stringent, the combustor designs move towards a “lean” burning solution where the fuel/air mixture contains more air to allow for complete combustion of the fuel while forming less pollutants. However, such combustor designs are more susceptible to instability due to thermo-acoustic driven pressure oscillations. Active control of such oscillations will allow for more efficient, lower emissions combustor designs. In recent years, there has been considerable research into combustion instability suppression. However, most of this research has been conducted with fairly simple laboratory combustors. The NASA GRC effort is focusing on development of more real test articles which will lead to improved modeling of the thermal-acoustic instability for actual combustors in an engine environment, and will eventually demonstrate the feasibility of active control of instability through engine tests.
Emission Minimizing ControlFor a given combustor design, it is possible to reduce the NOx (Nitrogen Oxide) emission through active control of the fuel/air mixture. The challenges for this technology are development of emission sensors for the harsh engine environment, development of simplified NOx production models that can be used for control design, and in investigating the most suitable approach to actively control the fuel/air mixture ratio.
Pattern Factor ControlThe Burner Pattern Factor is an indicator of the difference between the maximum and average temperature at the turbine inlet. Reducing the burner pattern factor through active control can eliminate some of the hot streaks at the turbine inlet, which will then allow for more efficient fuel burning, decreased emissions and increased life of turbine blades.
Project Contact
|
|
responsible official: sanjay garg |
