Modellgestützte Entwicklung von Kleinfeuerungen für feste Biobrennstoffe

Thesis of Winfried Juschka
Universität Stuttgart, 2019

To date, solid-biomass combustion appliances for residential heating have been developed by the experience of design engineers. Established development tools such as computational fluid dynamics (CFD) are not used in design in most cases. The models implemented in the CFD simulation have proven to be suitable. However, a detailed parameterization, in connection with measured values on prototypes, was the prerequisite for the CFD simulation so far. Thus, the previous CFD simulations were effective at the end of the development process only. In order to provide the developers with the right answers during the construction of the biomass firing system, the simulation must be performed at the beginning of the development process. A method developed and applied in this thesis enables to use the CFD simulation already at the beginning of the development process, i.e. parallel to the conception phase of a biomass firing system. The method enables to reliably predict the emission behaviour and the operating range of biomass boilers. Thus, when designing new biomass firing systems, the advantages of the CFD simulation can already be used in the conception phase, without the production of prototypes. With the method for the calibration of the simulation results, developed in this thesis, the optimal concept could be selected using the example of a log wood boiler operated batchwise. The subsequent metrological verification of two different log wood boiler prototypes on the test bench showed an excellent match of the measured carbon monoxide concentrations with the calibrated results from the CFD simulation.

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