Fuel spray injection will be a key element for enabling high-efficiency, low-emission engines of the future. Understanding the spray combustion process is critical, however, investigating engine combustion processes is challenging due to factors affecting the in-cylinder environment where mixing with fuel sprays occurs. The temperature, pressure, density, and composition of the in-cylinder gases and the fuel-injector conditions have a direct effect on combustion and emission-formation processes.
Unique installations available in the CRF’s Spray Combustion Laboratories can simulate a wide range of ambient (charge gas) environments at the time of fuel injection, allowing researchers to assess the effect of each variable with more control than can be achieved in an engine. There are two high-pressure and high-temperature optically-accessible chambers at the CRF: (1) A constant-volume vessel and (2) a constant-flow chamber. The capabilities for these facilities are listed in the table below:
|Parameters||Constant-volume vessel||Constant-flow chamber|
|Temperature range [K]||400 – 1700||300 – 1100|
|Pressure range [bar]||1 – 350||< 1 – 150|
|O2 concentration range [%]||0 – 21|
|Repetition rate||Every 5 min||Every 1-3 s|
CRF researchers use advanced laser and optical diagnostics to study the fundamental spray and combustion processes. Data obtained in these facilities are used to provide detailed understanding of the spray and combustion phenomena at relevant engine conditions. Beyond gaining fundamental knowledge about these processes, we use the information to improve computational fluid dynamic models, which in turn are used to optimize engine designs.
Understanding of sprays and injector flow is enhanced by using a unique transparent nozzle research vessel. As shown below, a regular diesel or gasoline injector is ground flat below the needle sealing surface and replaced with a transparent nozzle (acrylic or other transparent material). The transparent injector nozzles are manufactured with real size and shape compared to the original metal injector. The nozzles are mounted and sealed inside a small pressurized vessel and operated at realistic injection pressures (to 1000 bar). High-speed long-distance microscopy is applied to visualize the flow, cavitation, and gas exchange
An extensive dataset from this laboratory is available to download at the Engine Combustion Network, which seeks to advance state-of-the-art engine combustion modeling. An industry-sponsored consortium on spray combustion also uses these facilities to improve CFD engine design tools.
PIs: Lyle Pickett, Julien Manin
Please visit our other pages for more information about these collaborations: