Fasuliak V. Hydraulic calculations of pressure collector-pipelines with a discrete liquid inlet

Pressure collector-pipelines have found wide application in various fields of technology: water supply (water intake facilities with tubular heads, infiltration water intakes, radial water intakes, water purification facilities (quick filters); drainage systems of reclamation, water lowering (construction sites and built-up areas); water drainage (water drainage networks, sewage wastewater treatment facilities (biofilters for biological treatment, sand filters; heat supply (solar collectors); ventilation (exhaust systems); power engineering (steam pipelines-collectors, cooling towers); mechanical engineering (research stands, etc.) The flow of liquid in the collector-pipeline is formed due to the inflow of jets through the holes in its walls. Fluid consumption along the CP increases. Accordingly, the hydraulic head loss and energy consumption to create a high-speed flow head increase. The literature analysis shows that in the hydraulic calculations of pressure collector-pipelines, all authors take a constant value of the hydraulic coefficient of friction λ along the entire length of the CP. However, incomplete consideration of the design parameters of the CP and the hydrodynamic characteristics of the flow with variable path flow causes serious miscalculations in the design of the CP, which in turn weakens the efficiency of their operation. The purpose of this study is to reduce the unevenness of the flow of liquid to the pressure collector-pipeline, taking into account frictional pressure losses. The volume flow of liquid along the flow in the CP increases as a result of the inflow of jets. Accordingly, there is an increase in hydraulic pressure losses along the collector-pipeline. Neglecting the variability of the coefficient of hydraulic friction leads to serious errors in the calculation of CP. The differential pressure loss to overcome friction along the collector pipeline is expressed by us in terms of two variables - the total working pressure and the independent variable distance. Dependencies were obtained for the hydraulic coefficient of friction for the laminar flow regime of the liquid, which is implemented in the initial section, as well as for three sections of the turbulent flow regime: hydraulically smooth pipes, transitional and hydraulically rough pipes, which are located one after the other. Based on the differential equation of pressure movement of liquid with variable flow rate along the flow, an equation is obtained for calculating the inflow of liquid into the collector-pipeline through the holes in its wall for laminar flows with a variable value of the Darci coefficient. Also, under these conditions, a mathematical dependence was derived for calculating the full working pressure of the liquid flow in the collector-pipeline. An experimental stand has been assembled and described, with the help of which a study of the inflow of liquid into the pressure tank, which is mounted in a case, is carried out. The method of conducting experiments and processing the obtained results is described. Calculations and graphing were carried out using the Microsoft Excel program on a personal computer. The calculation of the total measurement error during the research on the experimental stand was carried out. It was established that it is 7.454%, which is within the regulatory limits. An analysis of the correspondence of the obtained theoretical dependences to the data of experimental studies was carried out. It was found that in certain intervals of the values of the Reynolds criterion, the unevenness of the water inflow along the path to the pressure collector-pipeline decreased with an increase in the parameters of the ReD criterion. If there is a transit flow of liquid in the CP at its beginning, liquid distribution may occur. The dissertation work is characterized by economic and ecological effects, has social significance and technical advantages in comparison with the known solution to the problem of optimization of the work of collecting pipelines. Invented "A method of regulating the flow of liquid into a pressure collector-pipeline and a device for its implementation" (Patent No. 128075 Ukraine IPC G05D 7/00, F17D 1/02, F17D 1/08, declared on 05/16/2022, published on 03/28/2024). The technical advantage of this method is the elimination of liquid distribution from the pressure tank in the presence of a transit flow at the entrance to the collector pipeline, and ensuring the inflow of liquid into the tank along its entire length. The materials of dissertation studies were introduced into the educational process of the Department of Hydraulic Engineering and Water Engineering, transferred to "TEO ENGINEERING" LLC (Lviv) and implemented during design work.