Computational Study of Interfacial Mixing in Pipeines, Logistics and Diverse Models to Predict the Interface Length

Abstract

Oil and gas are important resources of the U.S economy. Pipelines are the primary means of transporting oil and gas in the United States. Different grades of petroleum products are sent in the same pipeline as it is cost effective, which is known as batching. While two or more fluids are sent as a batch, mixing occurs at the interface of the two products known as "Transmix". Transmix varies in length and time across the length of the pipeline. Most of the study was done on developing the equation for the interface length and the factors influencing it. Factors influencing the transmix volume are pipeline length, pipe diameter, Reynolds number, kinematic viscosity of the mixture, mean flow velocity, friction factor, the type of flow regime and relative roughness factors. Software was developed to calculate the volume of the transmix and to predict how the above factors influence the transmix length. It was also observed that the elbows and bends increase the transmix length as the inter facial mixing occurs near the bends in the pipeline. Reducing the axial dispersion lessens the mixing in the pipeline which in turn reduces the transmix volume which is cost efficient to the oil and gas industry, as less product is sent for re-refining.