Unsteady-state inverse chlorine modeling in pipe networks

A model that directly determines the required source concentration(s) to me et specified chlorine residuals at selected nodes is developed for unsteady flows. The model considers even, over-, and underdetermined cases in which the number of available equations is equal to, greater than, or less than the number of unknowns, respectively. The model computes the unsteady-state flows and chlorine concentrations in the system first. Then it utilizes th e inverse method to determine the required source concentration(s) so that specified residuals at selected nodes match the calculated ones. To verify the model, chlorine concentrations' computed by the forward method are inpu t to the inverse model to determine the source concentration(s) in two hypo thetical networks. Results show that the model computed accurately the sour ce concentrations for the even and the overdetermined cases, but the result s were less than satisfactory for the underdetermined case.