Water supply system reconstruction in Fastiv (46000 inhabitants), Kyiv Region with a study of car wash elements
Students Name: Konyk Tetiana Zenoviivna
Qualification Level: magister
Speciality: Water Supply and Sewerage System
Institute: Institute of Civil Engineering and Building Systems
Mode of Study: full
Academic Year: 2022-2023 н.р.
Language of Defence: англійська
Abstract: The reconstruction of the water supply system of the city of Fastiv, Kyiv region, has been designed. The network is calculated for the maximum estimated cost, and the network is connected to the estimated cases. The source of the city’s water supply is the river. A channel water intake with a separate layout is adopted. The pumps of the pumping station of the first lift will pump raw water to the treatment facilities, where the water will be completely purified to the indicators that correspond to drinking water, for this purpose, preliminary cleaning with chlorine will be provided, and the movement of water through the main facilities, where the cleaning will be carried out qualitatively, by the pumping station of the second lift, in which seven Grundfos pumps, brand NBG 300-250-450/445 AF2ABAQE are installed, will pump already clean water to the city and the first consumers. The special part envisages a facility for local wastewater treatment after the car wash, namely from suspended substances and oil products, additional facilities for wastewater movement, storage, and cleaning are designed to meet the parameters of water recycling in the car wash. These measures are aimed at reducing the load on city-wide sewage treatment plants, minimizing anthropogenic impact on the environment and, in general, improving the stability of the ecological balance of natural ecosystems. Turbulent flows through sudden pipe constrictions are common in many industrial applications, including pipeline systems, aeronautics, slurry transportation, molding and extrusion. These local hydraulic resistances (LHDs) affect the flow structure upstream and downstream of the constriction plane. Therefore, they can be considered as a source of peculiar disturbances that lead to destabilization of the flow. According to the principle of operation, sudden pipe narrowings belong to the MGO, where there is a change in the cross-sectional area of the flow of the transported medium, in which the energy expenditure for the formation of annular vortices is predominant in local losses pressure Measures aimed at reducing energy losses due to the sudden narrowing of a round pipe should be effective at the degree of flow narrowing , where D, d are the diameters of the pipes that form this MHO. For pipeline transport systems, they should be implemented already at the design stage. These studies were conducted to investigate the implementation of new methods reducing the hydraulic resistance of a sudden narrowing of the pipe and reducing the unevenness of the road distribution of the family, reducing pressure losses at a symmetrical sudden narrowing of the pipe and avoiding hydrodynamic cavitation in the nozzles of the car wash water supply system. Methods of combining the theoretical foundations of hydraulics with setting up hydraulic experiments were used. One of the ways to reduce the hydraulic resistance of a sudden narrowing of a pipe is profiling with the help of various inserts. An insert with a rectilinear cylindrical generator, compared to others, has larger areas of flow separation. In addition, formulas and graphs are known for calculating the MGO coefficients of a sudden narrowing of a pipe with other inserts. Since the geometric simplicity of symmetrically narrowing channels does not lead to symmetrical flow, the coefficient of mutual influence of two sudden narrowings of the pipe was taken as for shut-off devices: straight-flow, in case of symmetrical flow, and non-direct-flow in case of asymmetric flow. In addition, to reduce the hydraulic resistance of the sudden narrowing of the pipe, you can use profiling with the help of inserts with curvilinear or rectilinear elements cut at an angle. Diaphragms of the water flow were provided by washers with hole diameters of 8 mm and 6 mm, installed on the working pipeline with an inner diameter of D = 17.8 mm in front of the model nozzle. The presence of hydrodynamic cavitation corresponded to the degree of narrowing of the water flow. In the experiments, the water consumption without diaphragm flow Qо = 0.1613 l/s. The use of a washer with a hole diameter of 6 mm led to mechanical vibration of the pipelines and acoustic noise. The reason is the reactive flow of liquid that is formed in the process. Therefore, in subsequent studies, such a diaphragm of the water flow was not carried out. Reducing the area of the live section of the model nozzle by diaphragming the flow in front of it significantly affected the water flow at the same pressure. Object of research - Symmetrical sudden narrowing of the distribution pipeline and nozzle of the water supply system of the car wash. The subject of research is the reduction of hydraulic resistance and the effect of hydrodynamic cavitation. The purpose of the study: to clarify the length of a straight cylindrical insert when profiling a sudden narrowing of a pipe, taking into account the mutual influence of two local hydraulic resistances (LHD) as locking devices. Elucidation of the effect of hydrodynamic cavitation on nozzles on the operation of the car wash water supply system. Results of the research. 1. The unnaturalness of the proposed method for calculating the length of a rectilinear cylindrical insert was revealed. 2. It is not recommended to use washers of accuracy class C with an opening diameter of d < 6.6 mm to diaphragm the flow on the nozzles of the working pipeline with an inner diameter of D = 17.8 mm., due to the significant impact of hydrodynamic cavitation on the operation of the sink water supply system auto. 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