A Study of Energy Released During Premixed Combustion

The paper* describes the analysis of experimental results of a laboratory flow apparatus used to measure the energy released during premixed combustion at atmospheric pressure in near quiescent air. The flow apparatus, described in a parallel paper, has the means to provide air temperatures in the range between 800 and 950° K. An infrared radiation detector and a photodiode sensitive to radiation in the visible range of the electromagnetic spectrum monitor the events taking place inside the combustion chamber through a sapphire lens. A beam splitter permits simultaneous observation of the combustion events by both sensors. The difference in response times between the two sensors offers information about the non-luminous premixed combustion. Four fuels, No. 2-D diesel fuel, a 50/50% volumetric mixture of diesel fuel and sunflower oil, neat sunflower oil, and neat high oleic safflower oil were used. The covariance analysis technique was selected for premixed combustion energy release study.

It was determined that fuel type, combustion air temperature, and fuel injection pressure have statistically significant effects on premixed burning, while injection fuel delivery rate does not. Fuel type and combustion air temperature have the strongest effects on energy output. The highest premixed energy output was measured for vegetable oils at low temperatures.