Researchers at Georgia Tech are showing-off what they say is a combustor with virtually no emissions of either nitrogen oxide or carbon monoxide — two main contributors to air pollution. Their design, which is modeled around an aircraft turbine engine, as opposed to the piston-driven combustion engine that's found in most cars, relies on a new and unique fuel delivery system. In current turbine combustors, fuel and air are usually premixed prior to it being injected into the combustion chamber. While the process helps to reduce emissions, the process is complex, expensive and difficult to control, say the Georgia Tech scientists who've taken a different approach.In the Georgia Tech engine, called the Stagnation Point Reverse Flow Combustor, the fuel and air aren't premixed. "We inject the fuel and air directly in the combustion chamber and they premix together before they ignite," says Dr. Ben Zinn, one of the project's key collaborators. The result is improved control of the combustion process and substantially-reduced emissions.
Dr. Zinn explained that in current combustors, the fuel/air mix ignites immediately upon injection, and burns at a very high temperature. It's this high temperature flame that results in high levels of nitrogen oxide emissions that contribute to smog. Unique to the new design is the fact that the fuel enters into the combustor on the same plane as it exits. In other combustors, the fuel is injected into one end of the combustion chamber, is burned, and the exhaust exits out the other. Not so in the Georgia Tech design, where the fuel-air mixture is injected and swings around the bottom of the combustor, burns, and then is exhaust out the same end it entered.
:: Via Discovery Online