In petroleum pipelines,non-Newtonian crude oils are generally pumped under turbulent flow conditions where the hydraulic design requires calculating the pressure losses due to friction.Without accurate estimation of the friction factor,friction pressure losses cannot be calculated.Despite of its significance,friction factor is a decisive challenge to be determined.This is due to the large number of friction factor equations and the precision of each. The main objective of the present paper is to answer this question by examining the published equations to select the most accurate one.Therefore,a comparative study among the available friction factor equations adopting Akaike information criterion,AIC and R~ 2 is intended.Data measured by several researchers are used individually and collectively. The results show that each model is accurate when it is examined with specific set of data while E&K model proves its superiority to other models when examining the data mutually.E&K offers not only a wide range of flow behavior index and generalized Reynolds number,but also gives more realistic and simple approach. It is also shown that the traditional believe of high R~ 2 means better model may be misleading.AIC overcomes the shortcomings of R~ 2 as it employs the parsimonious principle to trade between the complexity of the model and its accuracy not only to find a best approximating model but also to develop statistical inference based on the data.Yet,has not been used in our industry,the authors present the AIC to initiate an innovative strategy that has been demonstrated in other disciplines to help alleviate several challenges faced by the professionals in the oil and gas industry.Finally,a detailed discussion and models’ranking according to AIC and R~ 2 is presented showing the numerous advantages of AIC.
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