Browse Publications Technical Papers 2005-01-1723
2005-04-11

Comparative Study of Characteristics of Diesel-Fuel and Dimethyl-Ether Sprays in the Engine 2005-01-1723

A comparative study of characteristics of diesel fuel and dimethyl ether sprays was conducted on the basis of momentum conservation. The analysis reveals that the DME spray in the diesel combustion system may not develop as well as that of diesel fuel at high engine loads and speeds due primarily to the following reasons. (1) Because 42% more fuel volume must be injected into the engine to reach the diesel-fuel equivalent and because the DME injection pressure is lower than that of diesel fuel, longer injection duration for DME is needed even if with the enlarged orifice diameters. As a result, the penetration of the DME spray tends to be longer than that of diesel fuel. (2) Due to the enlarged diameter, the DME orifice becomes hydrodynamically short and the contracted fuel flow at the orifice entrance is not recovered fully; the still-diverging orifice flow at the orifice exit results in an increased angle for the subsequent spray. (3) Being less dense and more volatile than diesel fuel, DME has a higher gas-to-liquid density ratio in the spray, which also tends to increase the spray angle. Because of the large spray angle, the fuel-rich boundaries (due to the rapid fuel evaporation) of the DME sprays from different orifices of the injector tend to overlap under long injection duration and a strong swirl, which is unfavorable to complete combustion.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

Fuel Injection Strategy for Reducing NOx Emissions from Heavy-Duty Diesel Engines Fueled with DME

2006-01-3324

View Details

TECHNICAL PAPER

Thermochemical Characteristics of Dimethyl Ether - An Alternative Fuel for Compression-Ignition Engines

2001-01-0154

View Details

TECHNICAL PAPER

Experimental Study on the Combustion Process of Dimethyl Ether (DME)

2003-01-3194

View Details

X