Ammonia borane as a hydrogen-rich additive for cleaner and enhanced combustion of Biodiesel–Diesel Blends: Experimental insights

This study investigates the effects of ammonia borane (AB) additives at concentrations of 50, 100, and 200 ppm (designated B20A1, B20A2, and B20A3, respectively) on the droplet combustion characteristics of B20 biodiesel-diesel blends. Single-droplet combustion experiments were performed using high-speed imaging combined with MATLAB-based image analysis to quantify ignition delay, burn rate, combustion duration, and evaporation characteristics. Results revealed significant improvements in combustion performance upon AB addition. Specifically, ignition delays decreased by up to 49.4 %, and burn rates increased by approximately 23.2 % at moderate AB concentrations (100 ppm), facilitating enhanced combustion initiation and energy release. Additionally, AB additives shortened droplet evaporation duration by up to 26.8 %. However, excessively high AB concentration (200 ppm) led to agglomeration and inconsistent hydrogen release, adversely affecting combustion uniformity. These findings demonstrate the promising potential of AB as an additive to enhance biodiesel-diesel blend combustion, emphasizing the need for optimized concentrations to balance combustion efficiency with stable performance.