PDF Publication Title:
Text from PDF Page: 147
depressurization steps, which is unphysical indicating inadequate representation of the dynam- ics by the ROM at the optimum. Hence, these results also suggest that tight restrictions on decision variables and an adaptive trust-region based strategy with appropriate ROM updation is required for the ROM-based optimization. 6.6 Conclusions Beginning with a review of the previous work on model reduction, we describe how proper or- thogonal decomposition can be used to develop low-order approximations to PDE-based mod- els. In particular, with the method of snapshots, singular-value decomposition, and Galerkin’s framework, POD can be successfully used to construct reduced-order models which can be orders of magnitude smaller than the original model without losing accuracy. Methodology to construct ROMs is illustrated for a Skarstrom PSA process to separate hydrogen and methane. We not only show that the reduced-order modeling technique can be successfully used for large- scale models as well, but on the basis of the comparison made between the rigorous model and the ROM, we also conclude that such ROMs can provide significant model reduction and can mimic the dynamic behavior quite accurately at the same time. We also discuss that ROMs can be used to optimize in a confidence-region in the vicinity of the root-point assuming it is reasonably accurate in that region. Such ROM-based opti- mization in a trust-region is successfully demonstrated for two separate case studies of the hydrogen PSA process. ROMs accurately predict the descent direction in the trust-region and an improvement in the objective is obtained for both cases. Moreover, based on the CPU times observed, we conclude that ROMs enable fast and cheap optimization. Current results indicate that the proposed ROM-based methodology is a promising surrogate modeling technique for cost-effective optimization purposes. We vindicate that a trust-region is essential for ROM- based optimization, and conclude that an adaptive strategy with appropriate ROM updation is required. We develop such a strategy in the next chapter. 6.6 Conclusions Chapter 6. Reduced-order Modeling for Optimization 133PDF Image | Design and Operation of Pressure Swing Adsorption Processes
PDF Search Title:
Design and Operation of Pressure Swing Adsorption ProcessesOriginal File Name Searched:
anshul_thesis.pdfDIY PDF Search: Google It | Yahoo | Bing
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |