Simulation Of Compressors With The Help Of An Engineering Equation Solver
Julie Lebrun, Eric L. Winandy · Purdue e-Pubs (Purdue University System) · 2002
With the help of a so-called "engineering equation solver" it is possible today to write directly executable equations.This means that the modeling can be made fully transparent and easy to adapt to the specific needs of any user.First principle models are very easy to produce, with reference to classical engineering processes.A same set of equations can even be used for different tasks, as system sizing, parameter identification and simulation.A good way to ensure the model understandability is to start from fully physical approach (full whiteness), but also from simplest assumptions.These two options are compatible, if the real component considered is replaced by a set of elementary (well-known) processes, according to a "let's do as if" modeling scenario.The main benefits of this simplification are a better feeling of the user about sensitivities of the model and also a lower risk of mistake in input preparation and in output interpretation.The numbers of elementary processes considered can be increased progressively, until the model accuracy is considered as sufficient.The examples taken here are scroll and reciprocating compressors.They show how it is possible to get fairly simple reference models, which can be adjusted on the basis of experimental data.These "reference" models are developed in such a way to stay easy to understand and physically meaningful.Similarity variables are used as much as possible, in order to make easy and safe the identification of default value, whenever there is a lack in experimental data available.Each reference model can also be used as simulation "press-button", or run in such a way to generate a set of "robust" polynomial equations, easy to include in large system analyses.