Pressurized diesel diffusion flame topology detection by three-dimensional computed tomography

In this work, diffusion diesel flames injected by a single-hole nozzle under different injection pressures and ambient temperatures in a constant volume combustion chamber (CVCC) are reconstructed using three-dimensional (3D) computed tomography (CT), representing the first sets of 3D diffusion flame topology within the pressurized combustor. Initially, an optical measurement system comprising fiber bundle endoscopes and high-speed cameras is arranged around the CVCC to capture line-of-sight flame projections from multiple different orientations. Moreover, 3D flames are reconstructed based on the CT technique with enhanced accuracy designed for measuring facilities with restricted optical access. The instantaneous 3D flame topology and its evolution process are analyzed under different injection pressures and ambient temperatures. Compared to two-dimensional analysis, the 3D reconstructions manage to provide in depth investigations on spatial flame intensity evolution, representative turbulent flame patterns, ignition flame kernels merging process and internal void region detection, thereby facilitating a deeper understanding of the combustion process in CVCCs.