Experimental study on puffing and evaporation characteristics of jatropha straight vegetable oil (SVO) droplets

•Evaporation characteristics of jatropha straight vegetable oil (SVO) droplet.•Jatropha SVO droplet shows three-staged evaporation characteristics.•Evaporation mechanism of jatropha straight vegetable oil (SVO) droplet.•Puffing and micro-explosion are observed during jatropha SVO droplet evaporation.•For jatropha SVO droplet, bubble formation and rupture are seen at temperature 873 K. The present investigation studied the puffing characteristics and evaporation characteristics of jatropha straight vegetable oil (SVO) droplet under high ambient temperature in the experiments of single droplet evaporation. The effects of temperature on droplet normalized squared diameter and evaporation phenomenon were analyze. The results show that the evaporation characteristics of jatropha SVO droplet at 873 K are completely different from that at 673 K. The evaporation of jatropha SVO can be divided into three phases: transient heating phase, fluctuation evaporation phase and equilibrium evaporation phase. Puffing can be observed at both 673 K and 873 K; and, at 873 K, droplet deformation, bubble formation and expansion, jet and micro-explosion are also observed in the evaporation process. The increase of the ambient temperature is the main reason for improving the evaporation of jatropha SVO droplet, it is because there are many high volatile components in jatropha SVO which will first volatile to form bubbles and then make droplet puffing and micro-explosion under high temperature.