Imbalanced multiphase mixing through a narrow gap

Mixing through a gap of a two phase flow with unbalanced liquid or gas flow between adjacent channels was examined for a range of flow parameters and for two gap heights. Liquid mixing was calculated based on tracer concentration and flow rate measurements and gas net mixing based on wire mesh sensor data. Video of the mixing made visible by a fluorescent dye was analyzed with spectral proper orthogonal decomposition (SPOD) to glean further insight of the mixing mechanisms. Liquid flow Reynolds number was varied from 6 × 1 0 4 to 1 0 5 and gas volumetric quality up to 35% with imbalance up to 10% was examined. We had previously investigated balanced mixing in the same geometry. Reminiscent of what is seen in balanced flows, which are also further discussed, the gas affected the energy associated with the coherent modes based on SPOD of the video, with energy in 1 st mode reducing up to three orders of magnitude. As with the balanced flows, mixing was due to superimposed large coherent structures and the shear layer. However, an imbalance in either gas or liquid flow induces a pressure differential d P A B between the adjacent channels, which pushes the shear layer off the gap centerline. No significant effect of imbalance on mass transfer beyond that attributable to d P A B was found over the parameter range investigated. The mixing coefficient modification due to imbalance scaled nominally with the pressure coefficient defined based on d P A B .