AbstractBrine‐air and kerosene‐hydrogen systems were used for the mixed phase tests. No specific gas phase effects were detected. The measured variability, encompassing all three flow mechanisms, correlated well with particle Reynolds number for each system and decreased with increasing flow rate. However the variability component resulting solely from bulk liquid flow through the main bed channels was found to be relatively constant over a wide range of Reynolds number and independent of whether the bed was uniformly packed or contained large packing faults. The significance of these results to liquid‐solids contacting efficiency is disc