Non Intrusive Emission Detectin for Fleet Operation and Combustion Control

In this proposal, a novel method of detecting emissions from combustion systems using silicon carbide photodiodes is presented. Silicon carbide (SiC) photodiodes are responsive in the ultra-violet (UV) regime of the optical spectrum due to the wide band-gap characteristics of silicon carbide. These same characteristics allow SiC semiconductor devices to operate at temperatures up to 600K, rendering it especially useful for harsh environments such as combustion systems and aircraft engine exhaust systems. In the proposed work, SiC photodiodes will be used as sensitive emission detectors for combustion species such as hydroxyl (OH), carbon monoxide (CO), and nitric oxide (NO, NOx). The feasibility of using these sensors as emission detectors in jet engine exhaust plumes for fleet maintenance will also be demonstrated. The validity of the proposed concept will be demonstrated by comparing the SiC detection technique with standard laser based diagnostic measurements of the above combustion species. The use of the SiC photodiode for on-line combustion control will also be demonstrated in a laboratory environment. Due to small size and high temperature compatibility, the silicon carbide photodiode is ideal for on-line control applications.