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Full-Text Articles in Engineering

Two-Fluid Eulerian Simulation Of Bubble Column Reactors With Distributors, Abid Akhtar Jul 2006

Two-Fluid Eulerian Simulation Of Bubble Column Reactors With Distributors, Abid Akhtar

Abid Akhtar Mr

A two-fluid Eulerian model has been used to study the effect of various sieve plate gas distributors and gas superficial velocities on the hydrodynamics of three-dimensional flow in bubble columns. Turbulence has been modelled using the k-ƒÕ turbulence model. Inclusion of gas distributors showed asymmetric flow patterns which are otherwise smoothened when modelled using a uniform gas source. The asymmetric behaviour increased with increase in the number of holes giving better mixing. The gas hold-up increased with superficial gas velocity, and was independent of the distributor design at high superficial gas velocities. Comparison of simulation results with the experimental work …


Critical Hypersonic Aerothermodynamic Phenomena, John J. Bertin, Russell M. Cummings Jan 2006

Critical Hypersonic Aerothermodynamic Phenomena, John J. Bertin, Russell M. Cummings

Aerospace Engineering

The challenges in understanding hypersonic flight are discussed and critical hypersonic aerothermodynamics issues are reviewed. The ability of current analytical methods, numerical methods, ground testing capabilities, and flight testing approaches to predict hypersonic flow are evaluated. The areas where aerothermodynamic shortcomings restrict our ability to design and analyze hypersonic vehicles are discussed, and prospects for future capabilities are reviewed. Considerable work still needs to be done before our understanding of hypersonic flow will allow for the accurate prediction of vehicle flight characteristics throughout the flight envelope from launch to orbital insertion.