About one of the mathematical models of viscous flow incompressible fluid above sandy bottom

This paper presents the solution to the problem of determining the velocity field and the moment necessary to sustain the motion of a viscous incompressible fluid between two concentric infinite cylinders, rotating with constant but different angular velocities, when the radii of the cylinders vary axially. The solution is obtained for cases when the equations of slow motion govern the problem. The roughness of each cylinder is assumed small compared to the smooth radius; the roughness need not be small compared to the spacing between the cylinders. Results are explicitly obtained for the case of sinusoidal roughness.

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Thermodynamic analysis of dynamic processes in a centrifugal pump

Известия СПбЛТА ◽

10.21266/2079-4304.2017.221.197-217 ◽

2017 ◽

Author(s):

А.А. Куликов ◽

А.Ф. Смоляков ◽

И.В. Иванова ◽

И.Н. Дюкова

Keyword(s):

Mathematical Model ◽

Incompressible Fluid ◽

Mathematical Models ◽

Euler Equation ◽

Centrifugal Pump ◽

Thermodynamic Analysis ◽

Energy Exchange ◽

Dynamic Processes ◽

First Law Of Thermodynamics ◽

Pump Pressure

Предложена термодинамическая и математическая модель процессов энер- гообмена в центробежном насосе. Для процесса повышения в насосе давления несжимаемой жидкости получено выражение. Из первого закона термодинамики выведена формула для КПД центробежного насоса. Построена физическая и математическая модель, позволяющие получить уравнение Эйлера для лопастных машин из первого закона термодинамики. Показано, что термодинамическая и математическая модели, примененные для лопастных машин, могут быть использованы для анализа процесса дросселирования. The proposed thermodynamic and mathematical model of processes of energy exchange in a centrifugal pump. For the process of increasing the pump pressure of an incompressible fluid is obtained the expression. From the first law of thermodynamics the formula for the efficiency of centrifugal pump. A physical and mathematical model that allows to obtain the Euler equation for blade machines from the first law of thermodynamics. It is shown that the thermodynamic and mathematical models applied in kind for blade machines can be used for the analysis of process throttling.

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