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Direct Numerical Simulation

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Direct Numerical Simulation Of Supercritical Co2 Mixing And Combustion, Syed Mohammad Ovais Aug 2022

Direct Numerical Simulation Of Supercritical Co2 Mixing And Combustion, Syed Mohammad Ovais

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The supercritical CO2 power cycle (sCO2 ) is a relatively new technology, which promises to reduce CO2 emissions with potentially higher efficiencies. However due to challenging conditions posed by supercritical pressures, the mixing and ignition phenomena in sCO2 combustion is relatively less understood and studied. The primary objective of the current study is to investigate these fundamental processes using homogeneous ignition calculations (HMI) and direct numerical simulations (DNS). Broadly, the study is divided into two major parts. In the first part supercritical mixing in sCO2 relevant conditions is investigated. To achieve this, DNS of temporally …


On Simulation And Modeling Of Turbulent Non-Premixed Reacting Shear Flames At Low And High Pressure, Justin Foster Aug 2012

On Simulation And Modeling Of Turbulent Non-Premixed Reacting Shear Flames At Low And High Pressure, Justin Foster

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A database of simulations of fundamental turbulent H2/O2 and H2/Air shear layer flames has been developed using the direct numerical simulation technique in which all length and time scales of a flow are fully resolved without resort to turbulence modeling. The formulation includes the fully-compressible form of the governing equations, a pressure dependent detailed chemical kinetics scheme (9 species, 19 steps), a cubic real gas equation of state, realistic property models, and generalized heat and mass diffusion models. Simulations were conducted for a temporally developing shear layer geometry and cover a wide range of initial pressures (1 atm < P < 125 atm) and flame Reynolds numbers (850 < Re < 4500). These supercomputing simulations are the largest yet performed for high pressure conditions to the author's knowledge. Computational requirements for the largest simulations included mesh sizes of ~3/4 billion grid points and ~2.2 million CPU-hrs conducted on nearly 4,000 CPU cores on Clemson's Palmetto cluster.

The database …