Experimental and numerical examination of confined laminar opposed jets part I. Momentum imbalance

Impingement of laminar fluid jets in a confined cylindrical chamber is examined using flow visualization, laser Doppler anemometry (LDA) measurements and steady and unsteady three dimensional finite volume numerical simulations using boundary fitted non-orthogonal coordinates. The results presented here deal with the cases of flow imbalance issuing from the nozzles. Measurements and flow visualization of unequal flow cases with ∼3:1 flow rate ratios in an opposed two jet configuration indicate an asymmetric flow field with significant downward recirculation from the region away from the nozzles to the nozzle region and a jet-to-jet impingement point very close to the low flow rate nozzle. Steady and unsteady numerical simulations confirm the asymmetry of the flow field at these conditions and reasonable agreement is found for the jet-to-jet impingement point. Large areas of recirculation in the mix chamber will lead to poor mixing due to the possibility of unmixed fluid leaving the chamber and the increase in the residence time of the mixing fluids. The flow fields were found to differ significantly from equal flow studies previously completed.