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Field effects of buoyancy on lean premixed turbulent flames
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Dimalanta, R. Wernet, M. P. Cheng, R. K. Greenberg, P. S. |
| Copyright Year | 2001 |
| Description | Buoyancy affects the entire flowfield of steady turbulent flames and this aspect of flame buoyancy coupling is largely unexplored by experiments or by theory. Open flames and flames within large confinements are free to expand and interact with the surrounding environment. In addition to fluid and combustion conditions, their aerodynamic flowfields are determined by the flame brush orientation and geometry, wake of the stabilizer, enclosure size, and of course, the gravitational field. Because the flowfield consists mainly of cold reactants (mostly in the nearfield) and hot products (mostly in the farfield), buoyancy effects are manifested in the farfield region. In upward pointing flames, an obvious effect is a favorable axial pressure gradient that accelerates the products thereby increasing the axial aerodynamic stretch rate. Intrinsic to turbulent flows, changes in mean aerodynamic stretch also couple to the fluctuating pressure field. Consequently, buoyancy can influence the turbulence intensities upstream and downstream of the flame. Flame wrinkling process, and heat release rate are also directly affected. This backward coupling mechanism is the so-called elliptic problem. To resolve the field effects of buoyancy would require the solution of three-dimensional non-linear Navier Stokes equations with full specification of the upstream, wall and downstream boundary conditions. |
| File Size | 345908 |
| Page Count | 4 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20010074024 |
| Archival Resource Key | ark:/13960/t3dz56c3r |
| Language | English |
| Publisher Date | 2001-05-01 |
| Access Restriction | Open |
| Subject Keyword | Inorganic, Organic And Physical Chemistry Navier-stokes Equation Turbulent Flames Buoyancy Premixed Flames Flow Distribution Pressure Distribution Near Fields Particle Image Velocimetry Boundary Conditions Fuel-air Ratio Pressure Gradients Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
