Optimal reliability based design and analysis of pumping systems for water distribution systems.

摘要

Little has been reported in the literature on reliability analysis, particularly the optimal reliability based design of pumps and storage tanks for water distribution systems. This dissertation presents the development of new methodologies for the reliability analysis of pumping stations and the optimal reliability based design and analysis of pumping systems for water supply, including the optimal design of the pipe network.;The reliability analysis technique is based upon frequency and duration analysis using a supply model, a demand model, and a margin model. Using pump characteristic curves, the methodology models a continuous-time Markov process, using bivariate analysis and conditional probability approaches in the modifying traditional frequency and duration analysis. A computer code called RAPS has been developed to solve the methodology.;A reliability based optimization model has also been developed which is aimed at the following goals: (a) design of the optimal number, location and size of pumps and tanks, as well as the optimal pipe network; (b) design of optimal reliability based pumping systems for water supply considering both hydraulic failures and mechanical failures; and (c) determination of the optimal operation policy of pumps. A heuristic algorithm has been developed which consists of a master problem and a subproblem. The master problem is a pure 0-1 integer programming model and the subproblem, a nonlinear programming model solved in an optimal control framework. The conservation of flow and energy constraints are solved implicitly for each iteration of the nonlinear optimization procedure using the KYPIPE hydraulic simulation model and the reliability constraints are solved using the RAPS program. The nonlinear programming program is solved using the generalized reduced gradient code, GRG2.;Findings of computational results based on the model developed include: (a) optimal solutions obtained from traditional optimization techniques may not be reliable; (b) the number of pumps and tanks have considerable effect on water supply system reliability; (c) reliability requirements have significant impacts on system costs, and (d) the overall reliability based procedure tends to provide optimal pipe networks with more and smaller pipes.