A numerical study has been performed on a linear array of five nozzles in a lean direct injection (LDI) combustor for three mass flow rates and four different inter-nozzle spacings, using two equation realizable k − ɛ turbulence model. It is observed that the mass flow rates do not affect the flow patterns in this five nozzle configuration. The two smaller inter-nozzle spacings, s = 1.25d and 1.5d, developed asymmetric flow patterns. Especially at 1.5d, the asymmetry is quite dominant in the core flows of nozzles N2 and N4, due to the non-merging of jets in the shear layers. But, at higher nozzle spacings, s = 1.75d and 2d, the jets merge in the shear layers and move downstream as a single jet. Due to the slower expansion of the flow in the radial direction, strong and compact central toroidal recirculation zones (CTRZ) are formed at smaller inter-nozzle spacings, 1.25d and 1.5d. These compact CTRZs contribute to higher turbulence kinetic energy (TKE) in regions between the nozzles and closer to the dome-plate. These regions correspond to higher velocity and higher shear stress in the flow. As the inter-nozzle spacing is increased, the intensity of TKE decreases between the nozzles.
Part of proceedings: ISBN 978-1-62410-609-5, QC 20230117