Numerical Simulation Study On Motion Law And Deformation Characteristic Of Gelled Crude Oil Particle

The gelled crude oil hydraulic suspension conveying technology is a new breakthrough of unheated oil gathering and transportation. Under the action of a shaping device, gelled crude oil is made into particles and then mixed into low temperature water to realize hydraulic suspension conveying without being heated. Water-gelled crude oil two phase flow is a very complicated dynamic system which contains a variety of non-linear and non-equilibrium features. Meanwhile, the gelled crude oil particles have its definite interface as solid, but also have the characteristics of yield pseudoplastic fluid. The motion law and deformation characteristic have influence on the effect of hydraulic suspension conveying. It can promote the development of the technology to master them. In this paper, the motion law and deformation characteristics of gelled crude oil particle are studied by way of combining theoretical analysis and simulated computation.(1)In order to study the motion of gelled crude oil particle, water phase is regarded as turbulence flow model,while the gelled crude oi particle is regarded as DPM model. The inlet velocity distribution is given by the UDF. The calculation model of drag force coefficient is revised based the analysis of water gelled crude oil two phase flow. The trajectory and velocity variation under different conditions are got with Fluent software. The influence factors of particle size, particle density, releasing position, particle velocity and water velocity are analyzed. The results show, small vertical terminal velocity for gelled crude oil particle of little size and great density can help the particle avoid hitting the wall. The high velocity of water flow is helpful for gelled crude oil particle to get a increased distance in horizontal direction. The horizontal velocity of particle has nothing to do with its initial velocity, while the horizontal is synchronous with the change of flow field and mainly affected by releasing position. Ignoring the acceleration process, a model of the gelled crude oil particles collision is set up according to the principle of trajectories cross. The Matlab software is used to calculate the model and the calculated result is compared with the simulation result by Fluent software.(2)In order to study the deformation characteristics of gelled crude oil particle, the Herschel-Bulkey equation is used to describe its rheological properties and the VOSET method is used to track the interface. The deformation process of gelled crude oil particle is simulated by Fluent software. The result show, the deformation of gelled crude oil particle is influenced by the shear effect of field and the characteristics of particle, which include yielding and shear thinning. In the central region, shear stress is too small to overcome yieldvalue, so the deformation is difficult. When the particle is close to the wall, shear stress is enough to overcome the yielding value and the deformation increases rapidly with the effect of shear thinning. The influence of factors on deformation degree was analyzed, which include temperature, particle size, surface tension, and water flow rate. The results have show that the viscosity and surface tension inhibit the deformation of gelled crude oil particle, but a particle with big size is easier to deform. The effect of dimensionless number We to deformation degree is analyzed. At a higher We, the deformed degree is larger because inertial force is more obvious.