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论文类型：期刊论文

发表时间：2016-12-01

发表刊物：INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER

收录刊物：SCIE、EI、Scopus

卷号：103

页面范围：646-660

ISSN号：0017-9310

关键字：Multi-component oil; Evaporation; Pyrolysis; Lubricating oil; Abnormal combustion in natural gas engines

摘要：The auto-ignition of lubricating oil droplets in cylinder has been confirmed to be one of the major reasons of abnormal combustion in natural gas engines. A serial of fundamental experiments were carried out to elucidate the lubricating oil evaporation and pyrolysis behaviors under different ambient temperatures. An enhanced multi-component evaporation and pyrolysis model for lubricating oil droplets was presented. This model takes into account all key processes during the droplet lifetime, including the finite heat conduction and mass diffusion in the liquid phase, multi-component diffusion in the gas phase, as well as the pyrolysis and polymerization of high molecular-weight hydrocarbons in high temperatures. By comparing with the measurements of the droplet behaviors of lubricating oil and heavy oil, the present model shows good predictions of the droplet behaviors. Furthermore, this model was used to discuss the detailed behaviors of lubricating oil droplets in natural gas engine conditions. It is found that the lubricating oil droplets have significantly different behaviors from those of diesel and gasoline. They show slight pyrolysis and polymerization behaviors due to the high molecular-weight components. The heating period is crucial for the lubricating oil droplets, and the highest ratio of the heating period to the total droplet lifetime is up to 80%. The smaller droplet takes shorter time to get the high concentration of oil vapor surrounding the droplet surface than the larger droplet. (C) 2016 Elsevier Ltd. All rights reserved.