Executive Summary : | Role of low carbon or sustainable fuels and hydrogen along with their blends with conventional fuels is very crucial in our steps towards carbon neutral economy. There is thus a need to have deeper understanding of flame dynamics of these fuels to design better combustion based fuel utilisation systems. The proposed work will aim to understand flame dynamics of these fuels by studying flame-acoustic-turbulence interactions in premixed combustion. The coupling of intrinsic flame instabilities, turbulence and acoustic instabilities will be studied. Experiments will be carried out in a combustion tube and rectangular channel. A premixed fuel-air will be ignited and flame instabilities will be captured using high speed photography. Acoustic instabilities will be captured by pressure sensors. Effect of fuel properties on thermo-acoustic instability will be studied by mapping experiments on stability regime diagrams. Another important aspect of combustion systems besides flame stability is emissions. Effect of flame and acoustic instabilities on emissions will also be studied by measuring emissions from stable and unstable flames. Applicant's previous works have also shown promise to measure Markstein number (it signifies effect of flow perturbations on flame speed and is very important parameter to study turbulent flames). At present there is only one method to experimentally measure Markstein number which uses a spherically expanding flame. So, the alternate method to measure Markstein number using flame-acoustic interaction will be developed and further tested for various novel fuels. Flames in real combusts are usually turbulent. So, it is also necessary to understand effect of turbulence on flame-acoustic interactions. A turbulent flow field of known intensity will be generated in the experiments and flame propagating in a turbulent field interacting with the acoustic instability will be studied. This experiment will be developed as a benchmark which can be used for further detailed simulations. This work will generate fundamental understanding of flame-acoustic-turbulence interaction in novel fuels and help in burning clean in a stable flame environment. |