Comparative study of the accuracy of friction factor correlations developed for flow of inelastic yield power-law fluids in pipes

Abstract

An extensive review of the friction factor correlations used for pressure loss prediction of yield power-law (YPL) fluid flow in pipes has been conducted, and the results are summarized in this paper.A comparative study was also conducted to determine the predictive performances of various laminar and turbulent friction factor models developed for YPL fluid flow in pipes. Model predictions of frictional pressure losses were validated by comparing them with the experimentally measured pressure drop data obtained from the flow of several YPL fluids in pipes.Investigations were further extended to determine the impact of the variation of YPL fluid rheological characteristics (resulting from using different rheological characterization methods) on the pressure drop predictions.A wide range of generalized Reynolds numbers (i.e., 20 to 9000, as defined by the API-RP:13D) in a pipe flow configuration was considered in the analyses. The yield stress of the test fluids (determined by using the nonlinear curve fitting technique recommended by the API RP:13D) varied from 0.10 to 0.95 Pa.The results indicated that Hanks and Ricks' model predicted the pressure drop of YPL fluid flow in pipes better than any other models, both in laminar and turbulent flow regimes, matching the experimental data within a ±10% error range.Variations of the YPL model parameters (resulting from using different rheological characterization methods) significantly impacted the pressure drop predictions. Using YPL model parameters obtained from the non-iterative dual power law (DPL) approximation method (as recommended by API-RP:13D) and Hanks and Ricks' model yielded the most accurate pressure drop predictions for the pipe flow of YPL fluids.