Experimental investigation of evaporation characteristics of biodiesel-diesel blend droplets with carbon nanotubes and nanoceria as nanoadditives

The evaporation characteristics of biodiesel-diesel blends mixed with different concentrations of nanoadditives, namely, carbon nanotubes (CNTs) and ceria nanoparticles (NPs), at ambient temperatures of 673 K and 873 K under normal gravity were researched. The nanoadditives were dispersed in dosages of 50 ppm CNTs + 50 ppm NPs, 100 ppm CNTs + 100 ppm NPs, 250 ppm CNTs + 250 ppm NPs, and 500 ppm CNTs + 500 ppm NPs with 80% diesel blended with 20% jatropha biodiesel (B20D80). The results show that the nanoadditive has dual influence during evaporation processes at 673 K; the nanoadditives accelerate the evaporation rate at concentrations of 50 ppm CNTs + 50 ppm NPs and 100 ppm CNTs + 100 ppm NPs; conversely, they retard the evaporation rate at concentrations of 250 ppm CNTs + 250 ppm NPs and 500 ppm CNTs + 500 ppm NPs. However, the four concentrations of nanoadditives accelerate the evaporation rate at 873 K, whereas the level of evaporation acceleration is different. The CNTs has higher heat transfer efficiency than ceria NPs, whereas CNTs aggregate more easily and prolong the evaporation owing to their long length. Finally, the 100 ppm CNTs and 100 ppm NPs are suitable concentrations for nanoadditive in that it can effectively accelerate droplet evaporation at 873 K and 673 K.