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The hot forming process of steel requires temperatures of up to 1300°C. Usually, the invested energy is lost to the environment by the subsequent cooling of the forged parts to room temperature. Thermoelectric systems are able to recover this wasted heat by converting the heat into electrical energy and feeding it into the power grid. The proposed thermoelectric system covers an absorption surface of half a square meter, and it is equipped with 50 Bismuth-Telluride based thermoelectric generators, five cold plates, and five inverters. Measurements were performed under production conditions of the industrial environment of the forging process. The heat distribution and temperature profiles are measured and modeled based on the prevailing production conditions and geometric boundary conditions. Under quasi-stationary conditions, the thermoelectric system absorbs a heat radiation of 14.8 kW and feeds electrical power of 388 W into the power grid. The discussed model predicts the measured values with slight deviations.

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This paper evaluates a Eulerian-Eulerian modelling of the dispersed two-phase flow in pulverised coal combustion. In contrast to the commonly employed Eulerian-Lagrangian procedures, which treat the gas phase by a Eulerian and the particulate phase by a Lagrangian frame of reference, the presently investigated approach applies a Eulerian description to both phases. In our implementation, the model is further simplified assuming a mechanical and thermal equilibrium between the phases. For validation, two-and three-dimensional furnaces with different thermal loads have been analysed. Results have been compared to those obtained by Eulerian-Lagrangian formulations and measurements. It has been shown that the present Eulerian-Eulerian approach provides a comparable overall accuracy to the Eulerian-Lagrangian formulation, with substantially lower CPU requirements for large-scale utility boilers, and, thus provides an attractive alternative for this bracket of problems.

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Experimental and numerical investigation of isothermal flow in an idealized swirl combustorIf you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -The main purpose of the paper is the validation of different modelling strategies for turbulent swirling flow of an incompressible fluid in an idealized swirl combustor. Design/methodology/approach -Experiments have been performed and computations carried out for a water test rig, for a Reynolds number of 4,600 based on combustor inlet mean axial velocity and diameter. Two cases have been investigated, one low swirl and the other high swirl intensity. Measurements of time-averaged velocity components and corresponding rms turbulence intensities were measured using laser Doppler anemometer, along radial traverses at different axial locations. In the three-dimensional, unsteady computations, large eddy simulation (LES) and URANS (Unsteady Reynolds Averaged Navier-Stokes Equations or Reynolds Averaged Numerical Simulations) RSMs (Reynolds-stress models) are basically employed as modelling strategies for turbulence. To model subgrid-scale turbulence for LES, the models due to Smagorinsky and Voke are used. No-model LES and coarse-grid direct numerical simulation computations are also performed for one of the cases. Findings -The predictions are compared with the measurements and reveal that LES provided the best overall accuracy for all of the cases, whereas no significant difference between the Smagorinsky and Voke models are observed for the time-averaged velocity components. Originality/value -This paper provides additional valuable information on the performance of various modelling strategies for turbulent swirling flows.