Development of a Dry Low-NOx Combustor for the VT100 Automotive Gas Turbine

The design and development of a pilot assisted dry low-NOx LPP (Lean Premix Prevaporized) combustor for the VT100 turbogenerator is described. The combustor was designed for and tested on ethanol, a renewable biofuel chosen to minimize the contribution to atmospheric CO2. Engine specifications for pressure drop, operability and emissions have been met. The combustor has successfully demonstrated ultra low NOx and CO emissions below 10 and 20 ppmv respectively at the best engine conditions. The rig testing was performed at reduced inlet temperatures and the fuel flow was scaled to achieve main combustion zone flame temperatures as in the engine. The results show good agreement for NOx vs. flame temperature between the rig and engine tests. The dry low-NOx combustor for the VT100 turbogenerator meets the emission specification and gives the hybrid propulsion system the potential of meeting the foreseen (2010) NOx emission targets for urban delivery vehicles of 1 g/kWhe compared to today’s 7 g/kWhe.