Investigation of Fe₂O₃–Al and Cr₂O₃–Al reactions using a high speed video camera

Abstract

Self propagating high temperature synthesis is a simple, fast and energy efficient process with a wide range of applications, one of which is the coating of the internal surfaces of steel pipes using a centrifugal thermit process. The process involves a highly exothermic reaction between powder reactants distributed around a steel tube rotating at high speed. Although the process has been widely studied, important features, particularly how the reaction propagates, have not been completely revealed due to extremely high reaction rates and temperatures. In the present work, Fe 2 O 3 -Al and, to a lesser degree, Cr 2 O 3 -Al reactions were studied under stationary (non-rotating) and rotating conditions using a high speed video camera by which the centrifugal thermit process was, for the first time, recorded optically. Video recordings clearly demonstrate that, in contradiction to current belief, the reaction does not always propagate in a well ordered (spiral) pattern, but involves multiple, randomly distributed ignition sites.

Combustion Synthesis: An Update

“…Although the process has been widely studied, important features, particularly how the reaction propagates, have not been completely revealed due to extremely high reaction rates and temperatures. Menske et al videotaped Fe 2 O 3 -Al and, to a lesser degree, Cr 2 O 3 -Al reactions under stationary (nonrotating) and rotating conditions [74] . Video recordings clearly demonstrated that, in contradiction to the current belief, the reaction does not always propagate in a well -ordered (spiral) pattern but involves multiple, randomly distributed ignition sites.…”

“…Yet another additive used was ZrO 2 to provide a transformation toughening mechanism to the lining. Menske et al provided some fundamental understanding of the process mechanisms [74] . Although the process has been widely studied, important features, particularly how the reaction propagates, have not been completely revealed due to extremely high reaction rates and temperatures.…”

Onset of convection cells in a horizontally rotating cylinder partially filled with liquid

“…In such a case, fluid forms a film on the wall of the container. This rimming flow is not only scientifically interesting, but also important in engineering applications such as paper manufacturing (Pereira, Valenzuela & Valenzuela 2010;Ghosh 2011;Hubbe 2021;Majeed et al 2022), evaporators (Willems et al 2010Chatterjee, Sugilal & Prabhu 2019), centrifugal thermit process (Menekse, Wood & Riley 2006), centrifugal casting process (Keerthiprasad et al 2011;Boháček et al 2015) and triboelectric nanogenerators (Kim et al 2016). In fact, flow characteristics such as the instability of the rimming flow were extensively investigated experimentally, theoretically and numerically (Phillips 1960;Yih 1960;Johnson 1988;Thoroddsen & Mahadevan 1997;Hosoi & Mahadevan 1999;Tirumkudulu & Acrivos 2001;Ashmore, Hosoi & Stone 2003;Benilov, Benilov & Kopteva 2008;Kozlov & Polezhaev 2015;Kakimpa, Morvan & Hibberd 2016;Nicholson et al 2019;Sadeghi, Diosady & Blais 2022).…”

“…2022), evaporators (Willems et al. 2010; Chatterjee, Sugilal & Prabhu 2019), centrifugal thermit process (Menekse, Wood & Riley 2006), centrifugal casting process (Keerthiprasad et al. 2011; Boháček et al.…”

Fluid dynamics of the slip boundary condition for isothermal rimming flow with moderate inertial effects

“…These conditions describe a rimming flow, seen in Ruschak and Scriven's work on cream separation, 2 or an equivalent ceramic coating of pipes by Menekse, Wood, and Riley. 3 The addition of a slip boundary condition can be thought of as a first step in modeling film flow within a porous cylinder. Beavers and Joseph 4 show the shear stress in the film at the wall is proportional to the difference in tangential velocity between the film and the porous flow at that point.…”