An experimental variant of a commercial swirl burner for industrial gas turbine combustors operating at 3 bar is numerically investigated using high-fidelity Computational Fluid Dynamics models using STAR-CCM+ v11.06. This work presents the computational results of the SGT-100 Dry Low Emission gas turbine provided by Siemens Industrial Turbomachinery Ltd. The related experimental study was performed at the DLR Institute of Combustion Technology, Stuttgart, Germany. The objective of this work is to compare the performance of the Flamelet Generated Manifold model, which is the widely accepted combustion model in Gas Turbines with the Complex Chemistry model. In particular this work examines the flame shape and position, pollutant formation predicted by the aforementioned models with Large Eddy Simulations. Mean and RMS quantities of the flow field, flame temperatures and major species are presented and compared with the experiments. The results show that the predictions are insensitive on the meshing strategy and at the evaluated mesh sizes of ∼10 million and ∼44 million cells. The mean and RMS errors are ∼8% compared to the reported experiments and these differences are within the measurement errors. The results show that the calculated flame positions are in very good agreement with the reported measurements and the typical M-shape flame is reproduced independent of the combustion model. Pollutant formation in the combustor predicted by two combustion models is scrutinised. The predicted NO and CO emissions levels are in agreement with the literature.
As telecommunication and RF power electronics applications continue to push the envelope of waste heat dissipation, more and more, we see a need for active thermal control employing forced air electronic cooling fans in unison with pumped fluid loops in order to meet temperature and performance requirements. This research paper presents results of applying Computational Fluid Dynamics (CFD) commercial industry STAR-CCM+ software for heat transfer and fluid flow simulation of a novel heat exchanger/cold plate fabricated from k-core high thermal conductivity material in order to realize thermal control system hardware design for very much applications to very large power density (~1 kW/m 2) electronics packaging scenarios. Trade studies involving different heat exchanger/cold plate materials, as well as various fault scenarios within a mock-up of a typical electronics system, are used to illustrate the upper bounds placed on the convective heat transfer coefficient. Agreement between our present findings and previous research in the field of electronics cooling is presented herein.
Abstract. Large eddy simulations (LES) of gaseous buoyant turbulent flames have been conducted with the application of a flamelet based soot-radiation model. The subgrid model applies a turbulent eddy description of soot formation, oxidation and radiation and is based on the laminar smoke point concept. Two parameters, a local turbulent strain rate and prior enthalpy loss/gain fraction influence the soot formation and radiation. Radiation heat transfer is simulated by solving the finite volume discretized form of the radiative transfer equation (RTE) with the subgrid soot-radiation model implemented. The radiant heating of surfaces in close proximity of the flames is computed and predicted heat fluxes and surface temperatures are compared against experimental data. Fire growth in a rack storage arrangement is simulated with the application of a pyrolysis model. Computed heat release rate (HRR) is compared against experimental data. IntroductionThermal radiation, primarily due to soot, is responsible for fire spread in industrial scale rack storage scenarios. Flue spaces in rack storage setups are typically in the range of 0.15-0.6 m. Radiation in these spaces tends to be in the optically thin regime for moderately sooting pyrolysates from solid fuel surfaces. Accurate spatial and temporal prediction of radiant emission from the turbulent flame sheet therefore becomes the primary factor in predicting fire growth. This article presents results from CFD studies of (1) radiant heat transfer from a 60 kW propane fire to inert parallel panels [1], and (2) fire growth in an industrial-scale rack storage setup [2].Studies by Markstein [3] have established that radiation from turbulent buoyant diffusion flames correlates with the fuel's laminar smoke point height. Soot formation, oxidation and radiation all scale with the laminar smoke point. Using this concept, a model for soot radiation was developed by Lautenberger et al [4]. CFD simulations with this model showed good agreement of computed results with laminar diffusion flame experimental data. In turbulent flames the Kolmogorov micro-time scale governs the processes of soot formation, oxidation and radiation. This Kolmogorov mixing occurring in small reaction volumes must be described.A subgrid soot-radiation model based on the laminar smoke point model [5] is applied to compute radiant emission from buoyant turbulent diffusion flames. The subgrid soot-radiation model includes the effect of turbulence on the soot generation and oxidation rates. The model
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