Heat transfer and entropy generation in the parallel plate flow of a power-law fluid with asymmetric convective cooling

When drilling an oil well, a viscous fluid is injected to aid drilling. This fluid is also responsible for removing the cuttings and maintaining structural stability of well. The rheology of this drilling fluid has a direct influence on the cleaning of the well, on the dynamics of the fluid in pipe and annular areas. Linear mathematical extrapolations for high pressure and high temperature environments can lead to rheology errors up to 75%. In this study, a finite volume model was developed to simulate the flow of a water-based mud in annular and jetting environments in the drilling environment. Annulars were made by steel pipes and permeable formations. The fluids evaluated were developed empirically with xanthan gum and bentonite clay. The numerical results are consistent with literature and represent characteristics of a Yield Power Law fluid and a Bingham plastic. A comparison was made with water, allowing a correlation between rheological effects and fluid dynamics in annular and high vorticity regions.

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Numerical simulation of drilling fluid behavior in different depths of an oil well

The nonisothermal steady flow of a power-law fluid between two parallel plates is analyzed for different kinds of temperature boundary conditions and, moreover, with energy dissipation taken into account. It is assumed that the fluidity of the substance is a linear function of the temperature.

Nonisothermal generalized couette flow of a fluid with a power-law rheological characteristic

In this article, two optimal control problems of an extrusion process are considered in the isothermal case. The controlled system consists of a hyperbolic partial differential equation coupled wit...

Pontryagin's maximum principle for optimal control of an extrusion process

We employ the method of a small parameter to solve the problem of a pressure-stabilized Couette flow in which we take into account dissipation of mechanical energy and an exponential temperature dependence of viscosity.

Generalized couette flow with variable viscosity and dissipation of mechanical energy

We examine the nonisothermal steady-state flow of a Newtonian fluid between two parallel plates with consideration of the energy dissipation and in the assumption of a hyperbolic relationship between viscosity and temperature under various temperature boundary conditions. It is assumed that the upper plate is moving at a constant speed and that there is a pressure difference across the space between the plates in the direction of plate motion.

The critical conditions of the thermal regime in a generalized couette flow

The flow of a non-Newtonian fluid with an exponential rheological equation is investigated in the barrel of an extruder screw with consideration of the presence of circulating motion of the fluid in it.

Flow of non-Newtonian fluid between two coaxial cylinders under complex shear conditions

The flow of a liquid with an arbitrary anomalous viscosity-temperature characteristic through the channel of an extruder screw is analyzed taking account of the circulating flow, the energy dissipation, and the convective heat transfer.

Nonisothermal extrusion under continuous shear of liquids with an anomalous viscosity characteristic

Approximate relations suitable for engineering calculations are derived for determining the boundary of the core when the pressure gradient is given, the boundary and width of the core when the volumetric flow rate is given, and the pressure losses.

S. A. Bostandzhiyan

Papers

The critical conditions of the thermal regime in a generalized couette flow

Nonisothermal generalized couette flow of a fluid with a power-law rheological characteristic

Flow of non-Newtonian fluid between two coaxial cylinders under complex shear conditions

Nonisothermal extrusion under continuous shear of liquids with an anomalous viscosity characteristic

Axial laminar flow of a viscoplastic fluid in an annular tube