The optically accessible combustion vessel is a high-pressure combustion vessel which enables combustion studies including spray, ignition, and flame investigations at a maximum pressure of 345 bar (5000 psia) with full-field, multi-axis, optical access. This high-pressure vessel is based upon the design and operation of the Sandia National Laboratory combustion vessel (http://www.sandia.gov/ecn/dieselSprayCombustion.php). The vessel is formed by the intersection of three cylinders creating a cubical chamber with a volume of 1.1L. On each of the six faces of the cube is a removable sapphire window for nearly complete optical access to the combustion chamber. On each vertex of the combustion chamber, there are eight instrument and actuator access ports that contain valves, pressure transducers, etc.
With a gas mixing system including a 10L mixing vessel, the gas composition inside the vessel can be generated to provide an inert environment for the study of vaporizing non-reacting sprays as well as high dilution conditions over a range of percent oxygen. The same gas mixing system can be used to provide virtually any composition of gaseous fuels for combustion studies as well. The gas mixing system mixes up to seven components (of any gas desired), and is currently configured with O2, N2, CO, CO2, H2, C2H2, and CH4. The combustion vessel provides the ideal environment to investigate the fundamental spray, vaporization, and ignition characteristics of the gaseous and liquid fuels and supports advanced chemical kinetics, auto-ignition, and CFD combustion modeling efforts for these fuels.
The operating range of the combustion vessel in comparison to the TDC compression conditions of a naturally aspirated and a highly boosted, 10 bar boost, compression ignition engine. As can be seen the combustion vessel is able to attain and exceed the thermodynamic conditions experienced in advanced IC engines. It is also seen that the critical temperature and pressure for various fuels are often exceeded prior to fuel injection. The operational range of the combustion vessel not only covers the conditions expected in advanced engine technologies, but to conditions well above these. This is key since the engine efficiency and operation demands of the future will continue to rise.
The entire AFCL, including the gas mixing system, data acquisition, process control, and all safety and operator alert systems are separated from the lab in a control room and fully automated using A&D Technology data acquisition and process control equipment.