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Published in Bogumil Ulanicki, Kalanithy Vairavamoorthy, David Butler, Peter L.M. Bounds, Fayyaz Ali Memon, Water Management Challenges in Global Change, 2020
Bogumil Ulanicki, Kalanithy Vairavamoorthy, David Butler, Peter L.M. Bounds, Fayyaz Ali Memon
Nevertheless, if the calculated number of cycles is critical in a given pipeline, the designer should he prompted to moderate the amplitude of surges and/or cyclic frequency. This can be achieved by properly designed surge control devices, such as air chambers, surge tanks, pressure relieve valves, and others.
Design of a robust LMI-based model predictive control method for surge instability in interconnected compressor systems in the presence of uncertainty and disturbance
Published in Systems Science & Control Engineering, 2021
Cong Xie, Hashem Imani Marrani
Surge control is of greater importance in complex compressor systems consisting of several parallel and series compressors for which a higher fluid pressure increase is expected. A complex system consists of many components that interact with each other, and due to dependencies, competitions, relationships, or other types of interactions between their parts or between a given system and its environment; its modelling and controlling are inherently difficult (Ladyman et al., 2013). Systems that are ‘complex’ have certain characteristics that result from these relationships, such as nonlinearity, spontaneous emergence and order, compatibility, and feedback loops among others. The type of surge control system specified for a given system is largely determined by the type of compressor being used and the compressor system dynamics. If a system has a single compressor with a very steady behaviour, a simple control system may be appropriate. On the other hand, a complex system with multiple compressors, varying demand, and many types of end uses will require a more sophisticated surge control strategy. Due to the reciprocal effects of the compressors, their behaviour is more sensitive adjacent to the surge line, and thus a more careful control design is imperative. In any case, careful consideration should be given to compressor control system selection because it can be the most important single factor affecting system performance, efficiency and safety.
Robust decentralized model predictive control approach for a multi-compressor system surge instability including piping acoustic
Published in Cogent Engineering, 2018
Hashem Imani, Mohammad Reza Jahed-Motlagh, Karim Salahshoor, Amin Ramezani, Ali Moarefianpur
The cost function is defined by (11) with Q = I, R = 0.01. To demonstrate the various features of the proposed surge control method, a following scenario is performed on the compressing system with disturbance, change in throttle opening percentage and change in Spill Back valve gain. Compressors initially operate in steady state where the throttle valve openings equals to 20%. Spill Back valve gain is 0.1 and there is not disturbance in the system. At time t = 1s, the throttle is closed to 10% that makes the compressors experience surge. Appling the disturbance at time t = 5s will be exacerbated the surge effects. At time t = 9s, Spill Back valve gain is increased to 0.2 as the most difficult conditions that will cause changes in amplitude of surge. If the controller will not be activated, the compressors are interred into surge as shown in the Figures(3–5).
Surge explicit nonlinear model predictive control using extended Greitzer model for a CCV supported compressor
Published in Automatika, 2018
Hashem Imani, Hamid Malekizade, Hamid Asadi Bagal, Hasan Hosseinzadeh
The basis of the equations describing the flow in the compressor and the plenum volume comes from the Greitzer model in [7,8]. Assumptions for this model are low compressor inlet match number, low-pressure rise compared with ambient pressure, isentropic compression process in the plenum with uniform pressure distribution, and negligible fluid velocities in the plenum. The use of a close-coupled valve for surge control was accurately modelled and presented in [5,33]. The approach introduces a valve close to the plenum volume in the compressor. CCV means that there is no mass storage of gas between the compressor outlet and the valve, as can be seen from Figure 2.