Experimental investigations on spray flames and emissions analysis of diesel and diesel/biodiesel blends for combustion in oxy-fuel burner

Present research work shows the emissions and flame analysis of oxy-fuel combustion of diesel and diesel/biodiesel blends in the experimental test burner manufactured in Mechanical power engineering laboratory at Tanta University, Egypt. Diesel and a mixture of diesel and biodiesel (B0, B10, B20, B30, and B40) used as a fuel with the effect of pure air and oxy-combustion. Different emission parameters (carbon monoxide, carbon dioxide, unburned hydrocarbons, NOx, and soot opacity) and the flame parameters (flame cone angle and flame length) were also studied. It has been found that the emission parameters and the flame temperature are higher in diesel fuel than diesel and biodiesel blends for pure air combustion and oxy-combustion. It has also been found that flame parameters (the flame cone angle and flame penetration length) decreased by adding the oxygen into the charged air and increased by increasing the biodiesel mass percentage. The complete combustion of the fuel blends will dramatically increase the flame temperature due to the presence of a sufficient amount of oxygen for the early chemical reaction between fuel and oxidizer. These results indicated that the biodiesel could be the best alternative as well as an environmentally friendly fuel for diesel engines. - 2019 Curtin University and John Wiley & Sons, Ltd.Scopu

Hot deformation behavior and constitutive modeling of a cost-effective Al8Cr12Mn25Ni20Fe35 high-entropy alloy

Abstract In this study, a new non-equiatomic and cost-effective high-entropy alloy (HEA), Al8Cr12Mn25Fe35Ni20, was designed using thermodynamic parameters and prepared by arc melting. The alloy was subjected to homogenization at 1200 °C and a hot-rolling reduction of 50%. The hot deformation behavior and deformation mechanism were studied at varying strain rates ranging from 0.01 to 10 s−1 and temperatures ranging from 900° to 1100°C via plane strain compression tests using a Gleeble 3800 thermo-mechanical simulator. The phase structure of the rolled alloy was studied using electron backscattered diffraction (EBSD), X-ray diffraction, and differential thermal analysis to detect phase transformation. The constitutive model was implemented to predict the high-temperature flow stress using the Zener-Holloman parameter (Z), which correlated well with the experimental values. The studied HEA exhibited a relatively high activation energy for hot deformation of 389.5 kJ.mol−1, i.e., comparable to those of equiatomic HEAs in the literature. The hot-deformed microstructural features and deformation mechanism were studied using EBSD, which revealed discontinuous dynamic recrystallization as the main softening mechanism. Dynamic recrystallization (DRX) showed the formation of fine grains along the initial grain boundaries, accompanied by Al-Ni-rich B2 precipitates at the recrystallized grain boundaries