Parameterizing Compact and Extensible Compressor Models Using Orthogonal Distance Minimization
A complete and compact control oriented compressor model consisting of a mass flow submodel and an
efficiency submodel is described. The final application of the model is a complete two-stroke mean value
engine model which requires to simulate the compressor operating at the low flow and low pressure ratio area.
The model is based on previous research done for automotive-size compressors and it is shown to be general
enough to adapt well to the characteristics of the marine-size compressors. A physics based efficiency
model allows, together with the mass flow model, to extrapolate to low pressure ratios. The complexity
of the model makes its parameterization a difficult task, hence a method to efficiently estimate the
nineteen model parameters is proposed. The method computes analytic model gradients and uses them to
minimize the orthogonal distances between the modeled speed lines and the measured points. The results
of the parameter estimation are tested against nine different standard marine-size maps showing good
agreement with the measured data. Furthermore, the results also show the importance of estimating the
parameters of the mass flow and efficiency submodels at the same time to obtain an accurate model.
The extrapolation capabilities to low load regions are also tested using low load measurements from an
automotive-size compressor. It is shown that the model follows the measured efficiency trend down to low loads.
Xavier Llamas and Lars Eriksson
Journal of Engineering for Gas Turbines and Power,
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Last updated: 2019-03-29