Detection of nitrous oxide through IR-DFWM in gas flows with future application in ammonia flames

Sammanfattning: This thesis report on an investigation into the applicability of mid-infrared degenerate four-wave mixing (IR-DWFM) as a method to detect N\(_2\)O in ammonia flames. DFWM has previously been used for concentration measurements on other molecules, but has never, to the author's knowledge, been applied to measure N\(_2\)O in ammonia flames before. Through measurements in gas flows at different temperatures a transition was found which has potential to act as an identifier transition for N\(_2\)O in a ammonia flame environment. The P(39) transition in the combination band \(\nu_1+\nu_3\) was found to be a good candidate for the set-up available. Using this transition a detection limit of 2804 ppm was found at a temperature of 803 K. This detection limit is likely insufficient for N\(_2\)O detection in flames. However, using an upconversion detector, which has much higher sensitivity for detection of mid-infrared light, this detection limit could be improved enough that N\(_2\)O detection in flames is possible. Experimental data of N\(_2\)O concentrations in flames can be used as basis for evaluating computational models, and the same method can be used to estimate N\(_2\)O emissions from ammonia flames.