DYNAMICS OF THE PRESSURE FIELD DURING ISOTHERMAL FLUID MOVEMENT IN PIPES

Abstract

Background The classic work of N.E. Zhukovsky on hydraulic shock in water pipes was the beginning of a large Number of studies on pressure unsteady fluid movement. The large scale of construction of a network of high-pressure oil and gas pipelines was the impetus for setting the problems of unsteady traffic. In these tasks, you have to take into account the viscosity and compressibility of the liquid, as well as hydraulic resistance. Aims and Objectives In this paper, which is mainly intended for practical purposes, we consider the problem of the fluid pressure field in round pipes under the linearized law of friction. Results It is shown how a system of equations can be transformed into a single hyperbolic equation with respect to pressure, mass velocity, or velocity for a drop of liquid. The resulting equation is a special case of the well-known Telegraph equation. This establishes an analogy between the flow of liquid or gas in pipes and the distribution of electric current along the cable. As a specific problem, the solution of the equation describing the pressure under boundary conditions of the 1st kind is obtained, i.e. the pressures at the boundaries of the pipeline section under consideration are set. Using standard substitution, inhomogeneous boundary conditions are reduced to homogeneous ones. Calculations have shown that pressure fluctuations along the length of the pipeline occur only in the start-up mode. This period depends on many factors, but the main ones are the coefficient of hydraulic resistance and the flow rate.