5. Spray Chamber Designs and Optical Techniques for Fundamental Spray Investigations

In the present scenario, research in the area of Internal Combustion (IC) engines is mainly driven to address the alarming depletion of conventional fossil fuels and to control the tail-pipe emissions in order to comply with stringent emission norms. Combustion is one of the primary reasons for global warming; however, ~80% of total global energy production is based on combustion of conventional fuels. Hence, researchers have been trying to understand the in-cylinder combustion phenomenon to improve efficiency of energy conversion devices and new ways to utilize alternate fuels. Spray studies in engine-like environment play vital role in combustion and consequent heat loss to the cylinder walls. Fuel spray affects the air–fuel mixture formation, which is responsible for combustion and emission formation in the engine combustion chamber. To study mixing processes and spray distribution, in-cylinder conditions need to be simulated in constant volume combustion chamber (CVCC). Development of high-pressure high-temperature chambers and optical diagnostics involves lasers and high-speed cameras. These investigations enable us to understanding the insights into combustion that takes place in few milliseconds. This chapter starts with design of combustion chambers, followed by explanation of prominent optical techniques. This is followed by detailed discussions with the help of recent studies involving these chambers and techniques to understand spray atomization and combustion in different operating conditions. This chapter aims to give an understanding of different aspects of experimental spray studies and their impact in the field of IC engines.