Experimental study on the micro-explosion characteristics of two blended types of droplets under different nitrogen flow rates

Using the single droplet suspension method, the effect of nitrogen flow rate on the micro-explosion characteristics of L/H (low-boiling fuel in high one) and H/L (high-boiling fuel in low one) droplets in the laminar flow regime at 700 °C and atmospheric pressure was studied. The experimental results showed that for B80P20 (80% biodiesel and 20% 1-pentanol by volume) and B20P80 (20% biodiesel and 80% 1-pentanol), the micro-explosion intensity as well as the number of micro-explosions and strong micro-explosions increased first and then decreased with the increase in the nitrogen flow rate. In addition, the change range of B20P80 was always larger than that of B80P20. The micro-explosion intensity of B80M20 (80% biodiesel, 20% methanol) changed a little. However, for B20M80 (20% biodiesel, 80% methanol), it decreased monotonously with nitrogen flow rate. The variation of droplet lifetime was opposite to that of micro-explosion intensity except for B80M20. The micro-explosion delay time and relative micro-explosion delay time increased monotonously with nitrogen flow rate for B80P20, B20P80, and B20M80. As nitrogen flow rate increased, the micro-explosion distribution of B80M20 and B20M80 became more dense, but for B80P20 and B20P80, it became dense first and then sparse. In short, the nitrogen flow rate had a greater impact on H/L droplets than L/H ones, and a greater impact on B20M80 than B20P80. The experimental results provided a reference for further study on the micro-explosion mechanism of different blended types of droplets in different flow regimes.