An optical study on spray and combustion characteristics of ternary hydrogenated catalytic biodiesel/methanol/n-octanol blends; part Ⅰ: Spray morphology, ignition delay, and flame lift-off length. (1st April 2021)

• Record Type: Journal Article
• Authors: Xuan, Tiemin; Sun, Zhongcheng; EL-Seesy, Ahmed I.; Mi, Yonggang; Zhong, Wenjun; He, Zhixia; Wang, Qian; Sun, Jianbing; El-Zoheiry, Radwan M.
• Is Part Of: Fuel. Volume 289(2021)
• Publication Date: 2021-04-01
• Subjects: CI Compressed ignition -- UHC unburned hydrocarbon -- HCB Hydrogenated catalytic biodiesel -- C16 n-hexadecane -- C17 n-heptadecane -- C18 n-octadecane -- GCI Gasoline compressed ignition -- CVCC constant volume combustion chamber -- Fps frames per second -- FHWM Full width at half maximum -- ASOI After start of the injection -- ECN Engine Combustion Network -- CN Cetane number -- Zst Stoichiometric fuel mass fraction -- Pinj Injection pressure -- Ta Ambient temperature -- ρa Ambient density -- Pa Ambient pressure -- ID Ignition delay -- LOL Flame lift-off length -- ID* Calculated ignition delay -- ID Exp Experimental ignition delay -- d Nozzle orifice diameter -- U Theoretical velocity of the fuel at orifice outlet -- ρf Fuel density; Hydrogenated catalytic biodiesel -- Methanol -- N-octanol as cosolvent -- Optical study -- Spray and combustion; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2020.119762
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: Methanol was blended with hydrogenated catalytic biodiesel using n-octanol as co-solvent. The spray morphology, ignition delay, and flame lift-off length of the ternary blends were measured. The stoichiometric fuel mass fraction plays an important role on ignition delay. The effect of cetane number on flame lift-off length is more important than that of Zst. Abstract: A fundamental study on spray morphology, ignition delay, and flame lift-off length of two ternary hydrogenated catalytic biodiesel (HCB)/methanol/n-octanol blends were carried out by performing visualization tests through high-speed Schlieren and OH* chemiluminescence simultaneously within a quiescent combustion chamber. The two ternary mixtures are 68% by volume HCB, 17% octanol, and 15% methanol, as well as 58% HCB, 17% octanol, and 25% methanol, which are denoted as M15 and M25 respectively. It was found that the mixture stability of HCB/methanol is significantly enhanced using n-octanol as the co-solvent. The pure HCB (M0) was also tested under the same operating conditions as references. All the sprays were injected into the chamber through an injector equipped with a single-hole nozzle. Experimental results show that spray of M0 presents a faster penetration, following by M15 and M25, which is mainly caused by the shorter ignition delay of M0; With the increase of methanol percentage in the blends, the stoichiometric fuel mass fraction increases because of the high oxygen content of methanol, which contributes to a longer ignition delay; There are two factors of the blended fuel properties affecting flame lift-off length, namely stoichiometric fuel mass fraction and cetane number. It was found the cetane number plays a much more important role than that of stoichiometric fuel mass fraction on lift-off length.