Inter-scale energy transfer in turbulent premixed combustion

Kazbekov, Askar

Title:

Inter-scale energy transfer in turbulent premixed combustion

dc.contributor.advisor	Steinberg, Adam M.
dc.contributor.author	Kazbekov, Askar
dc.contributor.committeeMember	Lieuwen, Timothy C.
dc.contributor.committeeMember	Oefelein, Joseph
dc.contributor.committeeMember	Seitzman, Jerry M.
dc.contributor.committeeMember	Mazumdar, Ellen Y. C.
dc.contributor.department	Aerospace Engineering
dc.date.accessioned	2023-01-10T16:25:18Z
dc.date.available	2023-01-10T16:25:18Z
dc.date.created	2022-12
dc.date.issued	2022-12-07
dc.date.submitted	December 2022
dc.date.updated	2023-01-10T16:25:19Z
dc.description.abstract	Turbulent premixed combustion is widely used for energy conversion in power generation and propulsion devices. However, our understanding of the underlying fluid dynamics, combustion, and their interaction is still incomplete. The complexity of turbulent combustion arises from the non-linear, multi-scale, and multi-physics nature of the problem, which involves interactions between fluid dynamic and chemical processes across a myriad of length and time scales. The existing literature demonstrates that the dynamics of reacting turbulence does not necessarily follow the same phenomenology as in non-reacting incompressible turbulence. One of the key differences in reacting and compressible flows is the reversal of the classical turbulent energy cascade in a process termed as ‘backscatter’. Moreover, backscatter was shown to potentially depend on the magnitude of the pressure gradients across the flame; this is reflected in the sub-filter-scale pressure-work. Previous studies have predominantly focused on flames in homogeneous isotropic turbulence (HIT), in which the pressure gradients are associated with the flame and turbulence themselves. In contrast, practical combustors have mean pressure fields generated by the flow, which can induce significantly different turbulence dynamics as compared to non-reacting turbulence. The presented research explores the conditions at which energy backscatter occurs in an aerospace relevant configuration and attempts to identify the underlying physical mechanisms that have a leading order impact on these processes. This is done through systematic variation of the global equivalence ratio, the jet flow velocity, and the swirl number. The impact of these controlling parameters on turbulence production and energy backscatter is assessed through the analysis of filtered kinetic energy transport equations. Tomographic particle image velocimetry (TPIV) and planar laser induced fluorescence (PLIF) are used to measure the 3D velocity fields and planar distribution of formaldehyde, respectively; the relevant thermodynamic properties (e.g., density and progress variable) are estimated from PLIF data. Ultimately, this work provides both an assessment of the validity of current turbulence modeling paradigms employed in aerospace relevant combustion, as well as the data necessary to develop and validate new models if required.
dc.description.degree	Ph.D.
dc.format.mimetype	application/pdf
dc.identifier.uri	http://hdl.handle.net/1853/70169
dc.language.iso	en_US
dc.publisher	Georgia Institute of Technology
dc.subject	Turbulent combustion
dc.subject	Inter-scale energy transfer
dc.title	Inter-scale energy transfer in turbulent premixed combustion
dc.type	Text
dc.type.genre	Dissertation
dspace.entity.type	Publication
local.contributor.advisor	Steinberg, Adam M.
local.contributor.corporatename	College of Engineering
local.contributor.corporatename	Daniel Guggenheim School of Aerospace Engineering
local.relation.ispartofseries	Doctor of Philosophy with a Major in Aerospace Engineering
relation.isAdvisorOfPublication	7935aa46-f13f-4b9a-b224-0ae809a73226
relation.isOrgUnitOfPublication	7c022d60-21d5-497c-b552-95e489a06569
relation.isOrgUnitOfPublication	a348b767-ea7e-4789-af1f-1f1d5925fb65
relation.isSeriesOfPublication	f6a932db-1cde-43b5-bcab-bf573da55ed6
thesis.degree.level	Doctoral