Surge Detection System Using Gaussian Curve Membership Function

Abstract

ABSTRACT:Problem:Surge is an instability that affects the entire compression system. Surge is characterized by a limit cycle oscillation that results in large amplitude fluctuations of the pressure and flow rate. In contrast to rotating stall, during surge the average mass flow is unsteady but circumferentially uniform. Approach: The attempt to find a simple model structure which can capture in some appropriate sense the key of the dynamical properties of the physical plant, we study the application possibilities of the anti-surge detection system by using Gaussian curve membership function to protect the centrifugal compressor from surge by using Neural fuzzy. Results: By testing the new NeuralFuzzy system which has been created for demonstrate the validity of proposed control scheme, the new neural-fuzzy system get a good results compared by the used detection system. Conclusion: We can use Neural-Fuzzy system to detect the surge in centrifugal compressor Alternative to current detection system. KEYWORDS:Compressor, ASC, Gaussian, neural, fuzzy, ANFIS I.INTRODUCTIONCOMPRESSORS are used as part of a gas turbine for jet and marine propulsion or power generation, in superchargers and turbochargers for internal combustion engines, and in a wide variety of industrial processes .In this thesis we focus on centrifugal compressors that are used in (petro) chemical process plants and in fluid transportation pipelines. Centrifugal compressors have the same operating principle as axial compressors so whenever appropriate we will refer to the more general class of turbo compressors that covers all continuous flow compressors. [1] A Compressor transfers kinetic energy from an aero-mechanically-driven rotor to a steady flow of gas. The pressure of the gas is raised by converting the acceleration imparted by the rotating parts of the compressor via diffusion. In normal operation of a compressor, the flow is nominally steady and axisymmetric. The pressure rise is dependent on the speed of rotation, but the efficient range is limited. This instability can take on one of two forms, either surge or rotating stall depending upon the compressor speed. The performance of a compressor is plotted as pressure ratio versus mass flow for different rotational speeds. The plot is divided into two regions by the stall (or surge) line. This line defines the operation limits of the compressor. To the left of the stall line the flow is no longer steady. [2] During normal and slowly changing operations, surge can be avoided by recycling gas through the surge control valve to maintain a minimum flow. However, when a trip or major upset occurs, flow rate drops and the primary means by which surge energy can be reduced to lower the head (suction to discharge pressure difference) at which the compressor reaches the surge (minimum stable) flow condition. The head across a compressor during a trip or upset is dependent on the response of the entire system including changing performance of the compressor, transient flows within the piping, control sy...