Georgia Tech researchers report they have created a new combustor designed to burn fuel with next to no emission of nitrogen oxide (NOx) and carbon monoxide (CO). The device has a simpler design than existing state-of-the-art combustors and could be manufactured and maintained at a much lower cost, making it more affordable in everything from jet engines and power plants to home water heaters.
Called the Stagnation Point Reverse Flow Combustor, the Georgia Tech device, originally developed for NASA, burns fuel with NOx emissions below 1 parts per million (ppm) and CO emissions lower than 10 ppm, significantly lower than emissions produced by other combustors.
The project’s initial goal was to develop a low emissions combustor for aircraft engines and power-generating gas turbines. A traditional combustor mixes fuel and air before they are injected into the combustion chamber. Georgia Tech’s combustor injects the fuel and air separately into the combustor. The combustor burns fuel in low temperature reactions that occur over a large portion of the combustor. By eliminating all high temperature pockets through better control of the flow of the reactants and combustion products within the combustor, the device produces lower levels of NOx and CO and avoids acoustic instabilities that are problematic in current low emissions combustors.
To reduce emissions in existing combustors, fuel is premixed with a large amount of swirling air flow prior to injection into the combustor. This requires complex and expensive designs, and the combustion process often excites instabilities that damage the system. Georgia Tech’s design reportedly eliminates the complexity associated with premixing the fuel and air by injecting the fuel and air separately into the combustor. The combustor’s shape forces them to mix with one another and with combustion products before ignition occurs.
The project was funded by the NASA University Research Engineering Technology Institute (URETI) Center on Aeropropulsion and Power and Georgia Tech. The primary investigators on the project were Professors Ben T. Zinn, Yedidia Neumeier, Jerry Seitzman and Jeff Jagoda from the School of Aerospace Engineering, and Visiting Research Engineers Yoav Weksler and Ben Ami Hashmonay. – David Wagman