Necessity and ways to improve the calculation of a closed collector-drainage network of drainage systems

This paper presents the need and scientific-methodical approaches to improving the calculation of the closed collector-drainage network of water discharge systems. Based on the application of the system methodology, the structure of the hierarchical and hydraulic connection between the water regime of the field and the operation mode of the closed collector-drainage network has been established. The efficiency of the network is determined by the flow regime in the collector pipe as its main regulating element. As a result of the imperfection of the general theory of turbulent flow and the insufficient scientific explanation of the distribution of averaged velocities in the cross section of the pipe, we proposed improved scientific provisions based on the conducted theoretical and experimental studies. According to existing semi-empirical theories, models based on power and logarithmic profiles were proposed. The logarithmic profile has become widespread, despite the fact that this dependence does not correspond to the boundary conditions on the axis and on the inner surface of the pipes. To provide boundary conditions on the inner surface of the pipe, scientists have developed two-layer and three-layer models, but they also do not meet the boundary conditions along the pipe flow axis. In the theory improved by the authors, we took into account these shortcomings. These provisions, in contrast to the existing semi-empirical theories, describe and explain in formulas the influence of the hydrodynamic structure of the flow in the pressure collector pipe. This will allow, based on the application of the obtained universal equations, to construct a distribution profile of the total turbulent kinematic viscosity and the average flow velocity in the collector pipe. It becomes possible to evaluate the efficiency of the flow movement both in the constituent elements (collector pipes) and in the closed collector-drainage network. It also becomes possible to improve the methods of designing and calculating their technological and design parameters and, thereby, ensure the overall technical, technological, economic, and environmental efficiency of the drainage systems.