Pressure drop for single and two-phase flow of non-newtonian liquids in helical coils

New experimental results on pressure loss for the single and two-phase gas-liquid flow with non-Newtonian liquids in helical coils are reported. For a constant value of the curvature ratio, the value of the helix angle of the coils is varied from 2.56° to 9.37°. For single phase flow, the effect of helix angle on pressure loss is found to be negligible in laminar flow regime but pressure loss increases with the increasing value of helix angle in turbulent flow conditions. On the other hand, for the two-phase flow, the well-known Lockhart-Martinelli method correlates the present results for all values of helix angle (2.56-9.37°) satisfactorily under turbulent/laminar and turbulent/turbulent conditions over the following ranges of variables as: 0.57 ≤ n′ ≤ 1; Re′ < 4000; Re_l < 4000; Re_g < 8000; 8 ≤ _Χ ≤ 1000 and 0.2 ≤ De′ ≤ 1000.