Date of Award


Publication Type

Master Thesis

Degree Name



Mechanical, Automotive, and Materials Engineering


Alternative Fuels, Dimethyl Ether, Direct Injection, Fuel, Spray


Tjong, Jimi


Zheng, Ming




The primary objective of this thesis is to analyze the spray characteristics and behaviour of dimethyl ether (DME) in a high-pressure direct injection application. To achieve these results, two optically-accessible constant-volume chambers (CVC) will be used to observe the fuel spray development. An injector is instrumented inside the CVC and the injections are recorded with a high-speed camera. Various injection and background parameters are manipulated to study the effect of each parameter on the fuel spray characteristics and spray behaviour. Two types of experiments are used to study fuel spray, a quantitative study and an observational study. The first uses a direct imaging setup to measure the spray characteristics, e.g. spray penetration length and cone angle. The latter adopts a shadowgraph imaging technique to enhance the visual representations of vaporization around the fuel spray. In the first section of results, only the spray characteristics and vaporization behaviour of DME fuel will be presented and detailed. These will include results from both experiment types, the quantitative study and the observational study. In the second section of results, the corresponding sprays of diesel and n-butanol fuel are analyzed and compared to that of DME fuel. For a thorough comparison of the tested fuels, these experiments are subjected to the same testing parameters as used for DME fuel.