Oil Systems Modeling for an Operators ' Training Combined Cycle Plant Simulator
In this paper, the bases of the models of the oil systems of a full scope simulator of a 450 MW combined cycle power plant are presented. The simulator is executed in real time and was designed as support for the training of the operators. Here, the modeling methodology used to develop the referred models and the mathematical principles used to obtain the main equations are summarized. The tendencies of selected variables during transients and malfunctions are presented and analyzed in order to prove the validity of the simulator. Index Terms —Combined Cycle Power Plant, Oil System, Process Modeling, Real Time Training Simulator.
A Comparison of Rotordynamic-Coefficient Predictions for Annular Honeycomb Gas Seals Using Three Different Friction-Factor Models
A two-control-volume bulk-flow model is used to predict rotordynamic coefficients for an annular, honeycomb-stator/smooth-rotor gas seal. The bulk-flow model uses Hirs' turbulent-lubrication model, which requires a friction factor model to define the shear stresses at the rotor and stator wall. Rotordynamic coefficients predictions are compared for the following three variations of the Blasius pipe-friction model: (i) a basic model where the Reynolds number is a linear function of the local clearance, f s =n s Re m s (ii) a model where the coefficient is a function of the local clearance, and (iii) a model where both the coefficient and exponent are functions of the local clearance. The latter models are based on data that shows the friction factor increasing with increasing clearances. Rotordynamic-coefficient predictions shows that the friction-factor-model choice is important in predicting the effective-damping coefficients at a lower frequency range (60∼70 Hz) where industrial centrifugal compressors and steam turbines tend to become unstable. At a higher frequency range, irrespective of the friction-factor model, the rotordynamic-coefficient predictions tend to coincide. Blasius-based Models which directly account for the observed increase in stator friction factors with increasing clearance predict significantly lower values for the destabilizing cross-coupled stiffness coefficients.
The Use Of Honeycomb Seals In Stabilizing Two Centrifugal Compressors.
Fouad Y. Zeidan is Director of Engineer­ ing at KMC, Inc. , in West Greenwich, Rhode Island. Proir to joining KMC, Dr. Zeidan held positions at A moco Research Center, Imo Industries CentriMarc Division, and Qatar Fertilizer. He worked in maintenance and trouble shooting of rotating machinery, bearing design and failure analysis, vibra­ tion analysis, rotordynamic analysis, techni­ cal auditing of new machinery, and upgrading of existing equipment. At KMC, he is work­ ing in the design and development of radial and thrust bearings for oil, process, and gas lubricated applications. He received his B.S.M. E. (1978), M. S.M. E. (1979), and Ph.D. (1989) degrees in Mechanical Engineering from Texas A&M University.