Mathematical modelling of a hydraulic controller for PRV flow modulation

The main purpose of this paper is to describe a new experimental setup for testing static and dynamic behav-iour of the AQUAI-MOD® hydraulic controller coupled with a standard PRV, as well as to develop mathe-matical models which represent static and dynamic properties of such a system. The controller has been ex-perimentally tested to assess its performance in different conditions and operating ranges. The device in all cases has showed good performance by modulating the outlet pressure as expected between two points corre-sponding to the minimum and the maximum flow. The mathematical models of the controller have been im-plemented and solved using the Mathematical software package to represent both steady state and dynamics conditions. The results of the steady state model have been compared with experimental data and showed a good agreement in the magnitude and trends. The steady state model can be used to simulate the behaviour of a PRV and the AQUAI-MOD® hydraulic controller in typical network applications. It can be also used at the design stage and to compute the required adjustments for the minimum and maximum head set points before installing the controller in the field. Subsequently, a dynamic model of the PRV and the AQUAI-MOD® hy-draulic controller system has been developed and solved. Again the dynamic model showed a good agreement with the experimental data. The main time constant in the system model corresponds to the movement of the main element of the PRV. The research presented here has been carried out within the Neptune project (www.neptune.ac.uk) which is a Strategic Partnership between EPSRC, ABB, Yorkshire Water and United Utilities.