Rheological characteristics and flow laws of heavy crude oil in a pipe
The flow process of heavy crude oil has a strong historical memory and global correlation,and the classical Newton constitutive model cannot effectively describe its theological characteristics.In this paper,a spatial fractional constitutive model was established to well describe the rheological properties of heavy crude oil.Meanwhile,the flow and heat transfer processes were numerically simu-lated based on the finite element method(FEM).The influence of the fractional model order on the flow and heat transfer of crude oil was mainly studied,and the variations of the average Nusselt num-ber and the friction resistance coefficient with the spatial fractional order were analyzed.In addition,the changes of local Nusselt number and convective heat transfer coefficient during the heat transfer process of crude oil were compared under two thermal boundary conditions,namely,the constant wall tem-perature and the heat flux.The result showed that the rheological property of crude oil was known as shear thinning;meanwhile,the flow speed of crude oil was obviously improved and the heat transfer performance was effectively enhanced with the increase of order a(a＞1).Therefore,the rheological characteristics and flow as well as heat transfer laws of crude oil were deeply studied,which can provide theoretical guidance for further improving crude oil transport efficiency and economic operation in a pipe.
heavy crude oilpipefractional constitutive modelnumerical simulationflow and heat transfer
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