Pressure Drop and Heat Transfer Coefficients in Narrow Rotating Annular Clearances of Twin-Screw Multiphase Pumps

The evaluation of backflow rate and heat transfer in twin-screw multiphase pumps depends on the comprehension of the flow in narrow annular channels with rotation of the inner cylinder. In this pump, the peripheral clearance, which geometry recalls the cited narrow channels, is responsible for the most part of the backflow. This paper presents new generalized correlations to calculate pressure drop and heat transfer coefficients in such clearances. These correlations were proposed after a detailed review of several data of different authors. Results are compared with experimental data for different flow regimes with good agreement. The results show that the rotation of the inner cylinder – always ignored by previous works – can have significant influence over the backflow rate depending on operational conditions.