In this chapter a general introduction of centrifugal compression systems is presented. The unstable surge phenomenon in compressors is discussed, as well as possible means to avoid or suppress this instability. From an assessment of the current state of the art in control-oriented modeling and identification, the research objectives are formulated. 1.1 General introduction The general topic of...

A novel aproach to active surge control is presented for a centrifugal compressor driven by an electrical motor. The main idea of the paper is to use the drive itself for surge control. This eliminates the need for additional actuators, and has the potential of energy efficient operation. It is shown that previous unstable operating points to the left of the surge line can be made globally expo...

Torsional vibration problems continue to occur in reciprocating engine and compressor installations. This is due in part to the fact that reciprocating equipment can produce significantly more torsional excitation than rotating machinery such as turbines, centrifugal compressors, and centrifugal pumps. The purpose of this tutorial is to raise awareness of torsional vibration problems that can o...

This paper presents a steady-state model that is useful for predicting the performance of centrifugal liquid chillers over a wide range of operating conditions. The model employs an elemental NTU-E methodology to model both the shell-and-tube condenser and the flooded evaporator. The approach allows the change in heat transfer coefficients throughout the heat exchangers to be accounted for, the...

For over 15 years now, the efficiency and reliability of centrifugal compressors have been enhanced by the application of thermoplastic materials to the eye, shaft, and balance piston labyrinth seals. Traditionally these seals have been manufactured from metallic materials and have required relatively large clearances for reliability reasons. By upgrading to carefully selected engineered thermo...

Stringent stability screening criteria by the American Petroleum Institute (API) result in higher level rotor stability analyses to be performed on more intermediate-pressure compressor rotors and in more detail. These high-level stability analyses include predictions of impeller and seal rotordynamic forces and even extra effort on design and analysis of special damping devices as a backup, su...

Centrifugal compressor machinery is subject to a potentially damaging phenomenon called surge at low mass flow rates. This effect may be preceded by phenomena known as inlet recirculation — reversal upstream of the impeller. A methodology isolate characteristic feature for monitoring centrifugal instability presented in this study. The based on nonparametric time series analysis technique singu...

The following analysis is presented to serve as a preliminary design guide for micro turbine engine designers to consider the potential advantages of incorporating the Rampressor into their recuperated engine designs. It is shown that the increase in compressor efficiency and the shift in optimum pressure will increase the efficiency of the engine and lower the recuperator inlet temperature and...

This paper studies the dynamic pressure at outlet of 800 kW centrifugal compressor. It uses single-fractal method and empirical wavelet transform to analyze nonlinear characteristics compressor under different working conditions. First, it analyzes waveform when enters surge state from steady through transition process. also extract modal components waveform, which is reconstructed according co...