Measurement of nuclide cross-sections of spallation residues in 1 A GeV 238U + proton collisions

The production of heavy nuclides from the spallation-evaporation reaction of 238U induced by 1 GeV protons was studied in inverse kinematics. The evaporation residues from tungsten to uranium were identified in-flight in mass and atomic number. Their production cross-sections and their momentum distributions were determined. The data are compared with empirical systematics. A comparison with previous results from the spallation of 208Pb and 197Au reveals the strong influence of fission in the spallation of 238U.Comment: 20 pages, 10 figures, background information at http://www-wnt.gsi.de/kschmidt

Modelling Of Hydrocarbon And Nitrogen Chemistry In Turbulent Combustor Flows Using Detailed Reaction Mechanisms

The description of chemical kinetics in turbulent reactive flows is an important task to improve combustion models. This paper describes the inclusion of detailed chemical reaction mechanisms into the framework of a turbulent flame simulation. Calculations are based on a finite-volume solution procedure including submodels for turbulent flow, combustion of fuel and radiative heat transfer. The interaction of chemical reactions and turbulence is modelled using the Eddy Dissipation Concept (EDC). The basic idea of incorporating the reaction mechanism into the EDC is described. The oxidation of methane is described with a detailed C 1 /C 2 mechanism. The proposed model is applied to a 400kW turbulent diffusion methane flame in a cylindrical furnace. The measured trends in temperature and species concentrations of CH 4 , O 2 , CO and CO 2 are adequately reproduced by the predicted profiles. To demonstrate the benefits and limits of this approach, the method is applied to predict gas phase..

Numerical Simulation Of Utility Boilers With Advanced Combustion Technologies

This paper presents calculations of a pulverized coal flame and a coal-fired utility boiler with advanced combustion technologies. A combustion model based on an extended Eddy Dissipation Concept (EDC) combined with finite rate chemistry is described and some applications are shown. This model can be regarded as an extension of the previously used Eddy Breakup model (EBU) where infinite fast chemistry is assumed. It is part of a 3D-prediction code for quasi-stationary turbulent reacting flows which is based on a conservative finite-volume solution procedure. Equations are solved for the conservation of mass, momentum and scalar quantities. A domain decomposition method is used to introduce locally refined grids. Validation and comparison of both combustion models are made by comparison with measurement data of a swirled flame with air staging in a semi-industrial pulverized coal combustion facility. The application to three-dimensional combustion systems is demonstrated by the simulati..

NOx- REDUCTION WITH STAGED COMBUSTION - COMPARISON OF EXPERIMENTAL AND MODELLING RESULTS

INTRODUCTION The IVD of the University of Stuttgart carries out investigations of in-furnace DeNOx technologies using an electrically heated bench-scale test facility where the different process parameters are evaluated independently. The DeNOx technologies of air and fuel staging have been demonstrated to be effective control techniques to reduce NO x from coal-fired utility boilers. In order to assure a good reduction efficiency the process parameters temperature, stoichiometry and residence time must be carefully controlled. The importance of and interest in applying mathematical models is growing as they are a tool giving information about the combustion behaviour inside full-scale power station combustors. Until today discretization has been fairly coarse, and simple `global' reaction models are used for the pyrolysis of coal, the burnout of the char and the formation or reduction of NO. The NO formation and reduction in substoichiometric regions is strongly infl