Aspects of Fluid Flow and Heat Transfer in a Rapid Compression Machine

This work presents results on fluid flow and heat transfer characteristics relevant to a rapid compression machine. The relative contributions to the overall heat loss from the various surfaces that make up the machine enclosure are quantified. In addition, the flow and temperature fields present within the machine are studied to determine the degree of homogeneity of the temperature. The temperature distribution inside the RCM reactor and the crevice region is computed, and its statistical properties are evaluated over the entire domain. The development of the roll-up vortex in this piston – cylinder setup is examined in detail, and both the vortex path and its velocity are determined. The consequences of vortex formation for employing RCM in kinetic investigations are examined. The significance of the crevice, with particular emphasis on the amount of mass retained within it, is examined in relation to speciation research. This study further reveals how the interaction between the vortex and the wall is connected to its influence on the instantaneous rate of heat loss. Quantitative visualization is used to illustrate the primary features of the piston-driven flow and to demonstrate how it affects the local temperature field and the corresponding heat transfer rate. A criterion for determining an appropriate test duration for ignition delay measurements is developed based on the operating characteristics of the equipment. A comparison is also presented between the experimental pressure – time curve and the one obtained from the CFD simulations.