Simulation of Hydraulic Characteristics for Pipelines Consisting of Different Materials and Diameters

This paper deals with aspects affecting problems of coming up with a unified method for assessing the hydraulic compatibility of recovered and non-recovered sections of existing pipeline networks subjected to various methods of trenchless repairs. These issues are closely related to the problem of preserving the transporting ability of the wastewater fluid in a non-pressure pipeline during its trenchless renovation with polymer pipes. Theoretical approaches are given to determine the hydraulic parameters in the pipeline system, taking into account the renovation site and sites adjacent to a segment in question located up and down waste liquid fluid. It is shown that the priority measure to maintain the required degree of self-purification of the recovered pipeline section, as well as adjacent areas, is the magnitude of the water flow rate, which allows to provide required transporting capacity of the pipeline system. A formula to determine the length of the velocity destabilization zone is proposed, and the results of calculations using the automated program developed by the authors are put on display where algorithm includes dependencies determining hydraulic pipeline materials friction coefficients on different parameters as well as diameters, pipeline expanses and their slopes. The essence of the calculations, the sequence of input of the initial information using an automated complex, the type of output table information is described. Comparison of the counting results under different design conditions has been carried out. As conclusions, practical recommendations are presented in the way of managerial decisions for the potential achievement of hydraulic balance in a pipeline system and the creation of conditions under which the destabilization zone at the site after repairs is minimized and the number of preventive cleanings of the pipeline network is also reduced to a minimum.