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Research Abstracts Online
January 2010 - March 2011

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University of Minnesota Twin Cities
College of Science and Engineering
Department of Mechanical Engineering

PI: Paul J. Strykowski

CFD Studies of Non-Reacting and Reacting Flows in Combustors and Jets

These researchers are studying the backward facing step, a flow domain that they use as a prototype for a ramjet combustor design. Their efforts are aimed at increasing volumetric heat release rates at minimal drag/thrust penalty. Computational packages such as ANSYS, available through the MSI laboratories, can provide timely insight into salient features without the need for multiple physical models.

Gas jets, particularly those with variable properties relative to the surrounding fluid—examples include gradients in density and viscosity—are of particular interest as they provide a useful platform for studying global instabilities, which are important for efficient mixing with minimal stagnation pressure loss. The researchers employ ANSYS-CFX to shed light on why global instabilities are non-existent at high Reynolds numbers and/or thin boundary layers, and why they depend so critically on density and viscosity ratios. This research requires very careful probing of the near field of the jet, which is extremely difficult to investigate experimentally, but is rather straightforward computationally. Furthermore, these simulations can readily provide velocity and density profiles that are required for a linear stability analysis of the fluid flow, a useful theoretical tool for understanding the physics responsible for the observed behavior.

Group Members

Sumanta Acharya, Department of Mechanical Engineering, Louisiana State University, Baton Rouge, Louisiana
Aiman Alshare, Mechantronics Engineering, School of Technological Sciences, Amman, Jordan
Michael Hallberg, Graduate Student
Thomas Shepard, Graduate Student
Bo Yan, Undergraduate Student