Numerical study for critical fluid velocity in temperature-dependent pipes conveying fluid mixed with nanoparticles using higher order shear deformation theory

摘要

The pipelines are widely used in offshore oil and gas transportation which are undergoing instabilities generated by the internal fluid. This paper deals with the critical fluid velocity analysis of concrete pipes conveying viscous fluid-nanoparticle mixture. The structure is subjected to thermal load and the material properties are considered temperature-dependent. The well-known Navier-Stokes equation is used for obtaining the applied force of fluid to the concrete pipe. The fluid is mixed by AL(2)O(3) nanoparticles where the mixture rule is used for obtaining the effective density and viscosity. Based on higher order shear deformation theory of cylindrical shells, the displacement field of the pipe is considered. Utilising the energy method and Hamilton's principal, the motion equations are derived. The Galerkin method is applied for obtaining the critical fluid velocity of the structure. The effects of different parameters such as fluid velocity, volume per cent of nanoparticle in fluid, geometrical parameters of the pipe and temperature gradient are discussed on the critical fluid velocity of the structure. Numerical results indicate that with increasing the volume per cent of nanoparticle in fluid, the critical fluid velocity increase.