Experimental Study on Diesel Spray Characteristics at Different Altitudes Tongji University

Format:

Conference/Event

Author/Creator:

Wang, Wang, author.

Contributor:

Hu, Zhiyuan

Liu, Sheng

Lou, Diming

Tan, Piqiang

Yang, Zhenhuan

Conference Name:

WCX World Congress Experience (2018-04-10 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2018

Summary:

AbstractIn this study, effects of altitude on free diesel spray morphology, macroscopic spray characteristics and air-fuel mixing process were investigated. The diesel spray visualization experiment using high-speed photography was performed in a constant volume chamber which reproduced the injection diesel-like thermodynamic conditions of a heavy-duty turbocharged diesel engine operating at sea level and 1000m, 2000m, 3000m and 4500m above sea level. The results showed that the spray morphology became narrower and longer at higher altitude, and small vortex-like structures were observed on the downstream spray periphery. Spray penetration increased and spray angle decreased with increasing altitude. At altitudes of 0m, 1000m, 2000m, 3000m and 4500m, the spray penetration at 1.45ms after start of injection (ASOI) were 79.54mm, 80.51mm, 81.49mm, 83.29mm and 88.92mm respectively, and the spray angle were 10.9°, 10.8°, 10.7°, 10.4°and 9.8° respectively. The air-fuel mixing process was analysed using empirical relations like fuel spray area, spray volume, mass of air entrained within the spray and equivalence ratio. The decrease of spray area, spray volume and mass of air entrained were accelerate when altitude increased. At 1000m, 2000m, 3000m and 4500m, compared with 0m, the relative changes of spray area were 0.78%, 2.23%, 4.49% and 9.45% respectively, the relative changes of spray volume were 1.54%, 4.38%, 8.72% and 17.9% respectively, and the relative changes of mass of air entrained were 5.06%, 13.18%, 23.89% and 42.68% respectively, showing the negative effect of altitude was more obvious on the mass of air entrained due to the additive effect of spray volume and ambient density. Hence at a given incharge condition of a diesel engine at high altitude, it is necessary to intensify air-fuel mixing to improve oxygen utilization. When altitude increased, the higher axial equivalence ratio showed the quality of air-fuel mixing was deteriorated and similarly the relative changes of axial equivalence ratio also indicated the acceleration of the level of deterioration as altitude rose. Due to the narrower spray angle and smaller mass of air entrained, higher altitude provided larger and sharper distribution of radial equivalence ratio, indicating poor air-fuel mixing at high altitude

Notes:

Vendor supplied data

Publisher Number:

2018-01-0308

Access Restriction:

Restricted for use by site license