TY - GEN A1 - Schlegel, Martin A1 - Marquardt, Wolfgang A1 - Ehrig, Rainald A1 - Nowak, Ulrich T1 - Sensitivity analysis of linearly-implicit differential-algebraic systems by one-step extrapolation N2 - In this work we present an approach for the sensitivity analysis of linearly-implicit differential-algebraic equation systems. Solutions for both, states and sensitivities are obtained by applying an extrapolated linearly implicit Euler discretization scheme. This approach is compared to the widely used sensitivity extensions of multi-step BDF methods by means of case studies. Especially, we point out the benefit of this method in the context of dynamic optimization using the sequential approach. T3 - ZIB-Report - 02-38 KW - sensitivity evaluation KW - differential-algebraic systems KW - extrapolation methods KW - dynamic optimization KW - optimal control Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-7052 ER - TY - GEN A1 - Ehrig, Rainald A1 - Ofenloch, Oliver A1 - Schaber, Karlheinz A1 - Deuflhard, Peter T1 - Modelling and Simulation of Aerosol Formation by Heterogeneous Nucleation in Gas-Liquid Contact Devices N2 - This paper describes a new simulation tool for the prediction of aerosol formation and behavior in gas--liquid contact devices such as absorbers, scrubbers, quench coolers, and condensers as well as multistage gas cleaning processes, respectively. Aerosol formation can impact severely the separation efficiency of gas cleaning processes. Aerosol or fog formation can arise by spontaneous condensation or desublimation in supersaturated gas phases. The rigorous description of the mass and energy transfer between the gas phase, the liquid phase, and the growing aerosol droplets leads to a system of partial differential and algebraic equations. For the solution of these systems we have developed the plant simulation tool AerCoDe. This program bases upon the linearly--implicit Euler discretisation, which in combination with extrapolation permits an adaptive step size and order control. Typical simulation results of a multistage industrial flue gas scrubbing process are presented. It is shown, that experimental data can be confirmed if the number concentration of condensation nuclei as an input parameter is roughly known. T3 - ZIB-Report - 01-15 KW - aerosols KW - heterogeneous nucleation KW - two-phase flow KW - balance equations KW - extrapolation methods Y1 - 2001 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6416 ER -