Study on the effects of nanobubble-enhanced diesel spray technology on the performance of heavy-duty gas turbines

Nanobubble-enhanced diesel spray technology creates a stable nanoscale dispersion system by introducing gaseous nanobubbles into diesel fuel. This study selected air and methane as representative nanobubble gases to systematically investigate the effects of bubble type and concentration on diesel spray and combustion characteristics. Spray experiments employed Mie scattering imaging and micro-optical measurement techniques to analyze parameters such as spray cone angle, Sauter Mean Diameter (SMD), and droplet size distribution using various nanobubble-enhanced diesel fuels and under varying injection pressure conditions, thereby evaluating atomization performance. Combustion tests measured outlet temperature distribution factor (OTDF), CO, and NO x emissions using thermocouple grids and Fourier Transform Infrared Spectroscopy (FTIR) across varying nanobubble-enhanced diesel fuels and equivalence ratios to evaluate turbine performance. Bubble concentration significantly influenced atomization performance. Compared to conventional diesel, the highest concentration of nanobubble-enhanced diesel fuel reduced SMD by 14% and increased spray cone angle by 3.9%. For combustion, bubble type had a significant impact: methane bubbles increased NO x emissions by up to 13%, while air bubbles reduced emissions by up to 14%. Both bubble types reduced OTDF values and CO emissions. These findings provide crucial experimental and theoretical support for applying nanobubble fuels in heavy-duty gas turbines.