Research Projects

India has set a comprehensive decarbonization strategy committed to achieving net-zero emissions by 2070, as announced at the COP26 summit in Glasgow, by achieving 50% of its electricity from non-fossil sources by 2030. As a part of this road map, hydrogen co-firing in gas turbines can play a key role in reducing CO2 emissions. Excess energy from renewables can be conveniently stored as green hydrogen for later use as fuel. India's National Green Hydrogen Mission, launched in January 2023, is a major initiative to make the country a global hub for the production, usage, and export of green hydrogen and its derivatives. Currently, green hydrogen is expensive (around INR 400/kg in India), but long‑term estimates suggest green hydrogen could fall to INR 100-200 /kg in locations with abundant low‑cost renewables by 2050. Green hydrogen has a lower volumetric energy density than natural gas. However, per MJ basis, when its price falls to around INR 200/kg, it turns competitive with natural gas priced at INR 900–1200/MMBtu (assuming ~14.3 MJ/kg hydrogen). The energy mix in India currently lacks power from gas turbines due to the high per-unit cost of electricity generation. This project aims to develop technology to utilise hydrogen in gas turbines when there is an enhanced, affordable availability. One promising method to achieve complete hydrogen combustion in gas turbines, while maintaining high efficiency, flexibility, and low emissions, is the constant pressure sequential combustion (CPSC) concept. This approach represents a significant shift from traditional designs. Instead of relying on the usual method of flame propagation to keep the flame stable, it uses spontaneous ignition (autoignition) as the primary stabilization mechanism. This is realized using a two-stage combustor system. The first stage burns fuel with a conventional flame (similar to current gas turbines), while the second stage uses autoignition to continue combustion. Gas turbine combustion systems can experience thermoacoustic instabilities (fluctuations caused by the interaction of heat release and pressure waves) that may damage engine components over time, reducing reliability and service life. In sequential combustors, interaction between stages adds another layer of complexity to an already complex problem. As a result, the system can behave unexpectedly, leading to new types of dynamic behavior that are still not fully understood. To the best of PI's knowledge, research in CPSC systems is not being pursued in India. This project aims to investigate thermoacoustic instabilities in a lab-scale CPSC burner operating on natural gas-hydrogen blends. The hydrogen content will be more than 50% with attempts to use up to 100%. A CAD model will be designed and fabricated using preliminary CFD simulations and 1D acoustic model. The setup will be instrumented using PMT, pressure sensors, and thermocouples. A high-speed DAQ will be used to record high-frequency data under thermoacoustic instability conditions. NOx levels under various conditions will be measured using an emission analyzer. The experimental data obtained will be used to build an operational map of CPSC and a numerical model. The numerical model will use high-fidelity LES simulations with detailed chemistry to quantify and understand the combustion dynamics of the system. RANS-based model will be used to carry out parametric studies to investigate effects of swirl strength, air fuel ratio, heat release-acoustic coupling, and emissions. The numerical model will also be used for different parametric studies to minimise NOx emission for different operating conditions and hydrogen blend compositions. The numerical model will also be helpful in the design and development of an industrial-scale CPSB system. These outcomes directly address the challenge of decarbonizing and modernizing gas turbine technology for a net-zero future.