A Study of the Stability of Longitudinal Vorticies in a Poiseuille Flow Modulated by Periodic Wall Heating

The ability to enhance heat-transfer processes with a minimal amount of added energy expenditure has application in many industrial sectors. One avenue to pursue this is in the use of passive controls to trigger the promotion of secondary topological structures in a flow. These structures can be beneficial to the mixing and the transfer of heat into and out of the working fluid. In this instance, the influence of period heating and cooling patterns in the direction of the flow is considered with regard to the linear- stability of longitudinal vortices in a Poiseuille flow. The growth or suppression of these particular structures is investigated over an applicable range of flow parameters. Two physical arrangements are considered, the first case is that of only periodic wall heating being applied to the channel, while the second investigates the periodic heating’s impact on the stability of the flow in the instance of a heated lower wall

Comparison of Numerically Simulated and Experimentally Measured Performance of a Rotating Detonation Engine

A quasi-two-dimensional, computational fluid dynamic (CFD) simulation of a rotating detonation engine (RDE) is described. The simulation operates in the detonation frame of reference and utilizes a relatively coarse grid such that only the essential primary flow field structure is captured. This construction and other simplifications yield rapidly converging, steady solutions. Viscous effects, and heat transfer effects are modeled using source terms. The effects of potential inlet flow reversals are modeled using boundary conditions. Results from the simulation are compared to measured data from an experimental RDE rig with a converging-diverging nozzle added. The comparison is favorable for the two operating points examined. The utility of the code as a performance optimization tool and a diagnostic tool are discussed

Reduced-Order Modeling of Turbulent Reacting Flows with Application to Ramjets and Scramjets

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90621/1/AIAA-50272-117.pd

Absorption Spectroscopy In The 4.4-4.6 Μm Infrared Wavelength Range For The 10 Khz High-speed Measurement Of Co And Co2 Concentrations In Combusting Environments.

An instrument has been developed to make 10 kHz \textit{in situ} combustion gas measurements of carbon monoxide ($CO$) and carbon dioxide ($CO_2$) concentrations. Operating in both the 4.40 and 4.58 $\mu m$ wavelength ranges allows for the fundamental molecular absorption bands of both molecules to be utilized.\\ Such concentration measurements allow for the determination of total combustion efficiency of a particular process, which has engineering implications when considering the energy available from a combustion process to be utilized for propulsion purposes.\\ A brief discussion of the initial calibration of the sensor with a calibrated diffusion flame, Hencken burner, and pressure-concentration cell is made with the main focus of the current work being the application of the instrument to examine the structure of propagating detonation waves.\