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.
Study of the influence of the revolute joint model on the dynamic behavior of multibody mechanical systems : modeling and simulation
The influence of the revolute joint model on the dynamic behavior of multibody systems is investigated throughout this work. In the process, under the framework of the multibody systems formulation, a general methodology for modeling revolute joints with clearance is presented. The numerical models for normal and tangential contact forces are reviewed. The contact-impact forces developed during the contact are evaluated and introduced into the equations of motion of the multibody mechanical system. Moreover, the main kinematic and dynamic aspects of the modeling lubricated revolute joints are presented and discussed in this work in order to compare them with the dry revolute joint. The hydrodynamic forces are obtained by integrating the pressure distribution evaluated with the aid of Reynolds’ equation written for the dynamic regime. The hydrodynamic forces are nonlinear functions of the journal centre position and of its velocity with reference to the bearing center. The hydrodynamic forces built up by the lubricant fluid are evaluated from the state of variable of the system and included into the equations of motion of the mechanical system. The main assumptions and procedures adopted in this work are demonstrated through simulations of a slider-crank mechanism, which includes a revolute joint with clearance.© 2007 ASME
Microfiltration: Effect of retentate protein concentration on limiting flux and serum protein removal with 4-mm-channel ceramic microfiltration membranes.
The objective of our study was to determine if the limiting flux and serum protein (SP) removal were different at 8, 9, or 10% true protein (TP) in the microfiltration (MF) retentate recirculation loop using 0.1-µm ceramic graded permeability membranes with 4-mm-channel diameters operated at 50 °C using a diluted milk protein concentrate with 85% protein on a total solids basis (MPC85) as the MF feed. The limiting flux for the MF of diluted MPC85 was determined at 3 TP concentrations in the recirculation loop (8, 9, and 10%). The experiment was replicated 3 times for a total of 9 runs. On the morning of each run, MPC85 was diluted with reverse osmosis water to an MF feed TP concentration of 5.4%. In all runs, the starting flux was 55 kg/m(2) per hour, the flux was increased in steps until the limiting flux was reached. The minimum flux increase was 10 kg/m(2) per hour. The limiting flux decreased as TP concentration in the recirculation loop increased. The limiting flux was 154 ± 0.3, 133 ± 0.7, and 117 ± 3.3 kg/m(2) per hour at recirculation loop TP concentrations of 8.2 ± 0.07, 9.2 ± 0.04, and 10.2 ± 0.09%, respectively. No effect of recirculation loop TP concentration on the SP removal factor was detected. However, the SP removal factor decreased from 0.80 ± 0.02 to 0.75 ± 0.02 as flux was increased from the starting flux of 55 kg/m(2) per hour to the limiting flux, with a similar decrease seen at all recirculation loop TP concentrations.