Research Program of CFD and Propulsion Group

Link 1

Accurate, Robust, and Scalable Computational Methods for Large-Scale Simulations of Multi-Scale Physically-Complex Flows

In order to enable the more routine solution of multi-scale, physically-complex flows for practical applications in a predictive manner, rather significant advances in numerical methods and CFD algorithm design are required. Toward this end, research is continuing in the CFD and Propulsion Group on the development and application of a range of novel, accurate, efficient, and robust adaptive solution methods and models for describing multi-scale physically-complex flows using new and emerging high-performance computing (HPC) architectures. This research includes the development of: (i) high-order spatial (both finite-volume and novel flux reconstruction approaches) and temporal discreatization schemes; (ii) anisotropic body-fitted and hybrid (the latter involves a combination of multi-block body-fitted and more general unstructured grids) adaptive mesh refinement (AMR) meshing strategies with local solution-dependent refinement following from output-based error estimates; and (iii) efficient and highly-scalable parallel algorithm design for effective use of future heterogeneous HPC multi-core systems with floating-point accelerators.

Funding/Partners: Natural Science and Engineering Research Council (NSERC), Compute Canada

Link 2

Improved Numerical Combustion Models for Understanding and Predicting Soot and Other Pollutant Formation and Emissions in Aviation Gas Turbine Engines

Gas turbine engines are the primary propulsion device for today’s aircraft. These engines operate on liquid hydrocarbon-based fuels and as such can yield a range of undesirable pollutants including gaseous emissions such as nitrogen oxides (NOx), carbon monoxide (CO), green-house gases (GHG, largely CO2, really a combustion product) and unburned hydrocarbons (UHC), as well as nanometer-sized carbonaceous particulate matter (PM) or soot. Due to increasing concerns for the environment and causes of global climate change, the manufacturers of gas turbine engines are today facing increasingly more stringent governmental and/or environmental regulations pertaining to emissions. The CFD and Propulsion Groups is therefore pursuing research related to the development of new mathematical theory, combustion models, and more accurate and efficient numerical methods and tools for enabling improved predictions of emission processes in gas turbine engines. The research includes the development of improved moment closure methods for the formation, oxidation, and transport of nanoscale soot particulates as well as the radiative heat transfer in participating media for both laminar and turbulent flames.

Funding/Partners: Pratt & Whitney Canada, Green Aviation Research and Development Network (GARDN), Southern Ontario Smart Computing Innovation Platform (SOSCIP), IBM Canada, MITACS

Link 3

Improved Modelling for Dense and Disperse Regions of Liquid Sprays

The injection of liquid hydrocarbon-based fuels and the resulting atomization and spray formation processes have a direct impact on the combustion processes occurring in and the emmissions arising from today's gas turbine engines. The high-fidelity numerical modeling of the spray and atomization processes associated with liquid fuel injection systems in a relatively computationally efficient manner remains a major challenge for multi-phase combustion applications. Eulerian-based moment closure methods are proving to be very promising techniques for describing the disperse regime of such sprays, as they are well suited to high-performance computations and they provide a natural link with descriptions of the separate-phase flows of dense-spray regimes occurring upstream of primary atomization. The CFD and Propulsion group is conducting research into moment closure methods for spray applications. Various maximum-entropy inspired moment closure strategies for treating droplet size polydispersion, droplet velocity dispersion, and particle trajectory crossings associated with high inertial droplets are being investigated. Additionally, the coupling of the closure methods with spray breakup and atomization processes via empirically-based quasi-multiphase models are also being explored.

Funding/Partners: Pratt & Whitney Canada, IBM Canada, Ontario Research Fund (ORF), Canadian Foundation for Innovation (CFI) Southern Ontario Smart Computing Innovation Platform (SOSCIP), MITACS

Link 4

Development of LES Capabilities in Modeling Hydrogen Combustion in Slow and Fast Regimes for Application in Hydrogen Safety

The generation of hydrogen in nuclear power plants in case of a severe accident and the subsequent combustion is a safety hazard that can present a challenge to the containment integrity, thereby potentially leading to fission product release to the public. Design and implementation of hydrogen mitigation measures have to be based on reliable predictions of relevant phenomena (i.e., generation, distribution, combustion and recombination) that are greatly facilitated by the use of computer simulation codes. Sufficiently detailed analytical models are necessary to improve the confidence of these analyses. To address this shortfall, the CFD and Propulsion Group is pursuing the development of improved combustion CFD modelling and simulation capabilities for predicting hydrogen combustion in both the slow and fast regimes which are suitable for applications in hydrogen safety, both for the nuclear industry as well as future clean energy technologies. In particular, improved large-eddy simulation techniques and combustion models for the treatment of turbulent/chemistry interactions in premixed hydrogen flames are being investigated.

Funding/Partners: Canadian Nuclear Laboratories (CNL)

Link 5

Adaptive High-Order Magnetosphere Simulation of Space Weather

"Space Weather" is a term that is used to refer to conditions on the Sun and in the solar wind and geospace environment, which includes the lithosphere, hydrosphere, atmosphere, ionosphere, and magnetosphere, that can influence the performance and reliability of both space-borne and ground-based technological systems or can adversely affect human life or health on earth. The Sun and the resulting plasma environment within the heliosphere are the key drivers of space weather. As part of the “Geospace Observatory (GO) Canada – Science and Applications” program of the Canadian Space Agency, the CFD and Propulsion group is developing an advanced, made-in-Canada, data-drive, simulation module for space weather predictions in the heliosphere, solar wind, and Earth’s magnetosphere, using novel and leading-edge numerical simulation techniques. This simulation tool is also being applied to gain new insights into various space weather phenomena using Canadian geospace data.

Funding/Partners: Canadian Space Agency (CSA), National Resources Canada (NRCan) Geomagnetic Laboratory

Link 6

Numerical Modelling of Non-Equilibrium Gases and Plasmas

The development of novel theoretical and numerical approaches are being investigated by the CFD and Propulsion Group for efficiently predicting non-equilibrium, transition-regime, rarefied flows of gases and anisotropic plasmas using hyperbolic, realizable, maximum-entropy-based, moment closures which follow from kinetic theory. The hyperbolic, maximum-entropy-based, moment closures are particularly promising for the modelling micro-scale nonequilibrium gaseous flows and the treatment of fully and partially ionized anisotropic plasma. Moreover, the purely hyperbolic nature of the resulting moment equations makes the closures particularly appealing from a computational perspective, allowing accurate discretizations on AMR mesh.

Funding/Partners: Natural Science and Engineering Research Council (NSERC), Compute Canada