Investigation of Viscor and Methanol Spray Dynamics Using Proper Orthogonal Decomposition in Siemens Energy Industrial Atomizers

The demand to reduce carbon emissions has prompted research into alternative fuels that can replace conventional fuels like diesel in industrial gas turbines. Among different potential biofuels and e-fuels, methanol emerges as a sustainable and high-performance alternative to diesel for gas turbine applications. It is well established that the fuel physical properties, spray dynamics, and degree of atomization are strongly correlated and affect the engine performance. In this study, proper orthogonal decomposition (POD) was applied on spatiotemporally resolved images to characterize Viscor, here used as diesel surrogate, and methanol sprays of pressure-swirl atomizers employed in Siemens Energy industrial gas turbine (SGT-400) combustors. The methanol experimental results were then compared against Viscor results at analogous operating conditions, including density-adjusted atomizer pressure drop and ambient pressures. Results confirmed that methanol spray cone angle is slightly wider than Viscor at corresponding operating conditions. The POD analysis allowed to identify dominant spatial oscillation modes and characterize them in terms of oscillation amplitude, wavelength, and onset distance from the atomizer edge for both fuels. Oscillations wavelengths and maximum amplitudes were found to correlate with Weber number, average Sauter mean diameter (SMD), and axial jet velocities.