Conditional moment closure modelling of soot formation in turbulent, non-premixed methane and propane flames

Presented are results obtained from the incorporation of a semi-empirical soot model into a first-order conditional moment closure (CMC) approach to modelling turbulent, non-premixed methane–air and propane–air flames. Soot formation is determined via the solution of two transport equations for soot mass fraction and particle number density, with acetylene and benzene employed as the incipient species responsible for soot nucleation, and the concentrations of these calculated using a detailed gas-phase kinetic scheme involving 70 species. The study focuses on the influence of differential diffusion of soot particles on soot volume fraction predictions. The results of calculations are compared with experimental data for atmospheric and 3 atm methane flames, and propane flames with air preheated to 323 K and 773 K. Overall, the study demonstrates that the model, when used in conjunction with a representation of differential diffusion effects, is capable of accurately predicting soot formation in the turbulent non-premixed flames considered

Usury, statutory avoidance and the Court of Chancery 1680-1800

Article by Dr Warren Swain and Karen Fairweather, School of Law, Durham University published in Amicus Curiae - Journal of the Society for Advanced Legal Studies. The Journal is produced by the Society for Advanced Legal Studies at the Institute of Advanced Legal Studies, University of London

CO2 pipelines material and safety considerations

This paper presents an overview of some of the most important factors and areas of uncertainty affecting integrity and accurate hazard assessment of CO2 pipelines employed as part of the Carbon Capture and Sequestration (CCS) chain. These include corrosion, hydrate formation, hydrogen embrittlement and propensity to fast running ductile and brittle factures. Special consideration is given to the impact of impurities within the CO2 feed from the various capture technologies on these possible hazards. Knowledge gaps in the modelling of outflow and subsequent dispersion of CO2 following the accidental rupture of pressurised CO2 pipelines, central to their safety assessment, are also presented

The state of the responsible research and innovation programme: A case for its application in additive manufacturing

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Many of the ethical issues of additive manufacturing (AM) are not well known or understood, and there remains a policy vacuum that needs to be addressed. This paper aims to describe an approach that has been applied successfully to other emerging technologies, referred to as the responsible research and innovation (RRI) framework programme. A case is then made for the application of this approach in the AM industry with an illustration of how it might be used

Digital predictions of complex cylinder packed columns

A digital computational approach has been developed to simulate realistic structures of packed beds. The underlying principle of the method is digitisation of the particles and packing space, enabling the generation of realistic structures. Previous publications [Caulkin, R., Fairweather, M., Jia, X., Gopinathan, N., & Williams, R.A. (2006). An investigation of packed columns using a digital packing algorithm. Computers & Chemical Engineering, 30, 1178–1188; Caulkin, R., Ahmad, A., Fairweather, M., Jia, X., & Williams, R. A. (2007). An investigation of sphere packed shell-side columns using a digital packing algorithm. Computers & Chemical Engineering, 31, 1715–1724] have demonstrated the ability of the code in predicting the packing of spheres. For cylindrical particles, however, the original, random walk-based code proved less effective at predicting bed structure. In response to this, the algorithm has been modified to make use of collisions to guide particle movement in a way which does not sacrifice the advantage of simulation speed. Results of both the original and modified code are presented, with bulk and local voidage values compared with data derived by experimental methods. The results demonstrate that collisions and their impact on packing structure cannot be disregarded if realistic packing structures are to be obtained

The Rights of Religious Minorities

A travers l'évolution jurisprudentielle, l'auteur retrace la protection accordée au principe fondamental de la liberté de religion. Quel fut l'apport de la Charte canadienne des droits à cet égard ? La religion y fait l'objet de deux dispositions, soit l'article 2, et l'article 15 où est garanti le droit à l'égalité. La Charte se distingue des précédentes déclarations de droits en ce qu'elle insère la liberté de religion dans la Constitution du pays

Topics for rural social research

This report delineates a range of topics that could be included in MAF social research using mainly the suggestions available in the current sociology literature. Suggestions from five MAF personnel were used to supplement the literature. Both sources lead to a list of topics including the farm and the rural community, international linkages and consumers. In addition, there is a need for research on public opinion. The report suggests that an appropriate research strategy should include the development of a rural data base which is supplemented with farm and community studies using the full array of social science research methods. Agro commodity chains should be examined and rural public opinion regularly surveyed

CFD Simulation of Single- and Two-Phase Natural Convection in the Context of External Reactor Vessel Cooling

In recent decades, and with renewed importance after the events in Fukushima, the nuclear community has focused on the opportunity to rely on passive safety and, after plant shutdown, to ensure that reactor cooling can be safely guaranteed by natural processes, at least for a sufficient time before any active power intervention is needed. Buoyancy-driven flows and natural convection provide an efficient and potentially highly reliable and inexpensive heat transfer mechanism but, at the same time, these are rather complex flows because of the strong two-way coupling between the velocity and thermal fields, and the interaction between buoyancy and turbulence. In view of this, numerical tools able to predict these flows with accuracy and confidence are necessary to support the informed design and the safety assessment of present and future nuclear power plants. This paper is focused on research ongoing at the University of Leeds on the development of computational fluid dynamic tools to predict buoyancy-driven flows, of particular relevance to external reactor vessel cooling (ERVC). In ERVC, the aim is to retain the melted corium inside the reactor vessel, which is cooled from the outside by natural convection in the flooded reactor cavity where boiling is expected to occur on the outer vessel wall. The work starts by considering single-phase flow in a square buoyant cavity that is used to assess and improve the accuracy of available Reynolds-averaged Navier-Stokes (RANS) models, some of which, through the turbulence models embedded within them, are known to have shortcomings in predicting natural convection. In the same geometry, the superior accuracy of the large eddy simulation technique, the results from which may underpin further development of RANS approaches, is demonstrated. A two-fluid Eulerian-Eulerian model including boiling at the wall, which will be required to predict the whole ERVC phenomena, is also preliminary tested in the final part of the paper. Overall, encouraging results are found and weaknesses of the available modelling techniques and areas for future development are identified