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Large eddy simulations of pulverised coal combustion (PCC-LES) stabilised on a laboratory-scale piloted jet burner are carried out. The joint simulation effort of three research groups at Freiberg University (FG), Imperial College (IC) and Stuttgart University (ST) is presented, and the details of the comprehensive coal combustion models and their numerical implementation in three different computer programs are discussed. The (standard) coal sub-models and parameters used by the different groups are unified wherever possible. Differences amongst the groups are a different code basis and an Eulerian treatment of the coal particles by IC, while FG and ST use the Lagrangian framework for particle transport. The flow modelling is first validated for the corresponding non-reacting case and all LES calculations accurately capture the experimental trends. Velocity field statistics for the PCC case are in good accordance with the experimental evidence, but scalar statistics illustrate the complexity of coal combustion modelling. The results show notable differences amongst the groups that cannot only be attributed to the different treatment of the particle phase, and they highlight the difficulty to assess and interpret the quality of specific modelling approaches, and a need for further work by the research community. The present study is the first to compare three originally independent transient coal simulations and a step towards comprehensive PCC-LES

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Five different low-Mach large eddy simulations are compared to the turbulent stratified flame experiments conducted at the Technical University of Darmstadt (TUD). The simulations were contributed by TUD,

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Polymeric heart valves could offer an optimum alternative to current prostheses, by joining the advantages of mechanical and bioprosthetic valves. Though a number of materials suitable for this application have recently become available, significant improvements in the valve design are still needed. In this paper, a novel polymeric heart valve design is proposed and its optimization procedure, based on the use of finite elements, is described. The design strategy was aimed at reducing the energy absorbed during the operating cycle, resulting in high hydrodynamic performances and reduced stress levels. The efficacy of the design strategy was assessed by comparing the valve dynamics and stress levels predicted numerically during the cycle with those of an existing and well qualified polymeric valve design. The improved hydrodynamic performance of the proposed design was confirmed experimentally, by in vitro testing in a pulse duplicator.

Large Eddy Simulation (LES) has been applied to the swirling 100 kW th OXYCOAL-AC test facility of Aachen University. A set of models to represent devolatilisation, volatile combustion, char combustion and radiation for oxy-coal combustion in an LES framework has been implemented and tested. A qualitative analysis of the flow behaviour and the overall coal combustion processes occurring within the furnace was made. The LES results for the flow field were compared to axial and tangential mean velocity measurements, showing good agreement, particularly in the upstream regions of the flame. The LES results were also compared to oxygen concentrations and gas temperature. Overall good agreement was observed in the upstream central regions of the flame, whilst downstream the LES overestimated the combustion rates. The results show the potential of using LES for more complex oxy-coal combustion burners and opens the way for applications to industrial furnaces.

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