Investigation of Nitromethane Combustion Using Laser Induced Fluorescence

Abstract

Pre-mixed nitromethane/air/nitrogen flames on a heat-flux burner are investigated at atmospheric
pressure with equivalence ratios of =0.8 and =1.2. Flame thermometry and
chemiluminescence spectrum were used to characterise the flame before carrying out saturated
laser induced fluorescence on NO molecules. The temperature profile revealed three
zones of nitromethane combustion with maximum temperature of 1400K for the lean and
1350K for the rich flame. The chemiluminescence spectrum showed that numerous radicals
were produced and NO2 was responsible for the flame yellow appearance especially in
the lean case. TheNOconcentration profiles showed good agreement with global chemical
equation calculations and previous studies despite some differences. The results indicated
that nitrogen and NO are the main nitrogenous products of nitromethane combustion. The
results will be used to validate chemical kinetic models of nitromethane combustion.

Popular Abstract

Nitromethane is a liquid fuel mainly used in car racing. This is because it is capable of delivering more power compared to other fuels like gasoline for the same quantity of fuel. Interestingly, it also has potential to be used as a rocket fuel. The fuel has oxygen within its chemical structure which enables it to burn without the need for an oxidizer and its combustion produces fewer pollutants compared to hydrazine which is currently being used in rocket propulsion. This makes it a suitable replacement since environmental pollution is a global concern. Furthermore, the fuel is known to reduce soot emission when used together with other fuels in combustion engines. However, the combustion of this fuel is not completely known and therefore, more studies are needed to improve the understanding of the chemistry when the fuel burns. Hence this investigation of nitromethane combustion was performed using a laser-based technique.
Two flames with different fuel and oxidizer ratios were investigated at atmospheric pressure. A laser beam was sent through the flame to measure the concentration of nitric oxide at different heights above the burner. The interaction between the nitric oxide molecules and the laser beam produced radiation which was captured using a camera equipped to detect such radiation. The signal captured wasanalyzed to provide nitric oxide concentrations for information on flame behavior and chemical interactions. To enable the analysis and understanding of the detected radiation, the temperature and the radiation produced due to the chemical reactions within the flame were also recorded.
The results from the analysis showed good agreement with estimations of nitric oxide concentrations from the total nitromethane combustion chemistry and results from software models that predict the combustionof nitromethane. Furthermore, it was discovered that additional chemical species were being produced. Based on thatdiscovery, additional investigations into the combustion of nitromethane fuel for furtherdevelopment and validation of software models is planned for the future

• author: El-Busaidy, Said Ali Said
• supervisor: Elna Heimdal Nilsson
• organization: Department of Physics; Combustion Physics
• course: FYSM30 20161
• year: 2016
• type: H2 - Master's Degree (Two Years)
• subject: Physics and Astronomy
• keywords: Laser Induced fluorescence Nitromethane Combustion Chemiluminescence
• language: English
• id: 8876702
• date added to LUP: 2016-06-08 09:36:22
• date last changed: 2016-06-08 09:36:22