Numerical Simulation of Conjugate Heat Exchange at Gas Flowing in a Well

A mathematical model is offered for conjugate heat exchange when gas flows in the section of a vertical well. The motion of the medium is described using a two-dimensional axisymmetric stationary formulation based on boundary-layer equations. The turbulent gas flowing due to the reservoir energy is considered. Natural gas is taken as a travelling medium. The numerical simulation results are presented in the form of the dependences of the flow temperature and gas density along the radius of the well on the external factors of the heat exchange changing along the well height. The results describe the thermobaric state of the well in the condition of the conjugate heat exchange of the produced natural gas flow and tubed well depending on the external thermal conditions.

Numerical simulation of conjugated heat exchange in the turbulent motion of fluid in an oil well

The mathematical model of conjugate heat exchange is proposed for the turbulent movement of reservoir oil in a vertical well section. The motion of the medium is described using a two-dimensional axisymmetric stationary formulation and boundary layer equations. The movement of the turbulent flow of reservoir oil due to reservoir energy is presented. The liquid medium is a mixture of reservoir oil with dissolved gas and formation water. The results of the numerical modeling are presented in the form of dependences of the changing flow rate, temperature, and mass fraction of paraffin deposits that occur along the full vertical extent of the well. The results obtained describe the thermobaric state of the well under the condition of conjugate heat exchange between the fluid flow and the production pipe.

ВЛИЯНИЕ УГЛОВ ПОЛОЖЕНИЯ КАМЕР НА НАРУЖНЫХ И ВНУТРЕННИХ ЧАСТЯХ ГИДРОСТАТОДИНАМИЧЕСКОГО ПОДШИПНИКА СДВОЕННОГО ТИПА НА ЕГО НЕСУЩУЮ СПОСОБНОСТЬ

The task is to study the bearing capacity of the double type bearing at different angular positions of the chambers on the outer and inner working surfaces. It is given a mathematical model of a double type hydrostatodynamic bearing in a stationary formulation, which makes it possible to determine its bearing capacity. It is considered the cases of laminar and turbulent flow of the working fluid in the slit path of the double type bearing. Both gradient and portable flows of the working fluid are considered in recording the flow of working fluid along the contour of the 1st chamber. The expression for the flow rate of the working fluid at the entrance to the chambers is written for the case of using the jet as a pressure compensator. The cost balance equations and the Reynolds equations, written for both the outer and inner working surfaces of the double type bearing, were solved jointly. Applied assumptions are usually taken in the hydrodynamic theory of lubrication in writing the Reynolds equations. The most common V.N. Constantinescu method was applied for turbulence coefficients. The expression for the balance of expenditure equations and the Reynolds equations are expanded to the dimensionless type. The most effective numerical methods for the numerical implementation of the expenditure balance equations and Reynolds equations are analyzed and applied. The most economical finite-difference method in combination with the longitudinal-transverse sweep method was applied to solve the Reynolds equation. The accuracy of the solution was assigned when determining the pressures in the chambers and on the inter-chamber jumpers. Geometric and operating parameters of the double type bearing were assigned based on currently existing recommendations for the design of fluid-friction bearings. The results of the calculation of the bearing capacity of the double type bearing for different camera angles on the external and internal parts of this bearing are obtained. The results of the calculation of the bearing capacity of the double type bearing in the form of graphs are given. The analysis of the obtained results was made and conclusions were made on the obtained results, allowing designers to more efficiently design bearings of this type.

NUMERICAL STUDY OF NATURAL CONVECTION IN ENCLOSED VOLUME

A numerical study of natural convection was conducted with Code Saturne soft ware package. A numerical model based on combined k-ω SST turbulence model was developed. The results of simulation of natural convection in enclosed volume of air were obtained in two variants of boundary conditions specification: by heat flux and by heat transfer coefficient. The problem was solved in a non-stationary formulation using a pressure-velocity coupling algorithm PISO. This simulation model adequacy is evaluated. Experimental data on the temperature profile in the central section is used as a benchmark criteria. Assumptions about the destructive factors reducing the accuracy of the solution, are partly supported by the results of comparative analysis of the intensity of convective mixing. Assumptions partially confirmed by the results of comparative analysis of the intensity of convective mixing, performed on the basis of upward velocity profiles for the heated air.