| 1. |
- Westerberg, Lars-Göran, et al.
(författare)
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Transport under compression of bubbles in a non-Newtonian fluid
- 2011
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Ingår i: International Journal of Transport Phenomena. - 1028-6578 .- 1540-0069. ; 12:3-4, s. 161-176
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Tidskriftsartikel (refereegranskat)abstract
- Bubble transport is of importance in many applications for non-Newtonian fluids, such as in the manufacture of composite materials where residual bubbles may impair electrical properties, surface appearance and the mechanical properties of the finished products. In this study, a model experiment is performed where a non-Newtonian fluid (grease) containing bubbles is compressed between two plates, whereby the motion of the bubbles is tracked and evaluated using Particle Image Velocimetry. The bubble motion is furthermore analytically modelled and coupled to the experimental results.
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| 2. |
- Liberman, M. A., et al.
(författare)
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Numerical Simulation of Deflagration-to-Detonation Transition : the Role of Hydrodynamic Instability
- 2006
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Ingår i: International Journal of Transport Phenomena. - 1028-6578. ; 8, s. 253-277
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Tidskriftsartikel (refereegranskat)abstract
- The role of the flame folding, induced by the classical Darrieus-Landau instability, on the transition from deflagration to detonation is studied by numerical simulations of premixed gas combustion spreading from the closed end of a semi-infinite, smooth-walled channel. It is found that in sufficiently wide channels the Darrieus-Landau instability may invoke nucleation of hot spots within the folds of the developing wrinkled flame, triggering an abrupt transition from deflagrative to detonative combustion. The mechanism of the transition is the temperature increase due to the influx of heat from the folded reaction zone, followed by autoignition. The transition occurs when the pressure elevation at the accelerating reaction front becomes high enough to produce a shock capable of supporting detonation. This requires the fold to be sufficiently narrow and deep. The influence of adhesive and rough walls on the transition is discussed.
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| 3. |
- Rokni, Masoud, et al.
(författare)
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A study on turbulent flow characteristics in ducts of relevance for heat exchangers
- 2004
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Ingår i: International Journal of Transport Phenomena. - 1540-0069. ; 6:3, s. 225-226
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Tidskriftsartikel (refereegranskat)abstract
- The performance of an explicit algebraic stress model with a cubic equation for closure constants is assessed in predicting the turbulent flow dynamics of ducts relevant for heat exchangers. The use of a cubic equation allows elimination of any damping functions in the tensor representation for the Reynolds stresses and thereby improves prediction of turbulent stresses theoretically. The methodology used here allows for prediction of Cm in any spatial points and eliminates the use of damping functions in the turbulent viscosity. A flow parameter, which characterizes the flow type from plane strain and plane shear to elliptical flows, is used to prescribe the flow type in the ducts under consideration. In all cases, isothermal conditions are imposed on the duct walls, and the turbulent heat fluxes are modeled using a new bounded quadratic generalized gradient-diffusion type model. In addition, the calculated results are compared with existing experimental data and satisfactory results are obtained. A comparison of velocity and temperature contours is shown in order to study the effect of waviness on flow/heat dynamics.
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| 4. |
- Yuan, Jinliang, et al.
(författare)
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Transport Phenomena Coupled by Chemical Reactions in Methane Reforming Ducts
- 2009
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Ingår i: International Journal of Transport Phenomena. - 1540-0069. ; 11:1, s. 39-50
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Tidskriftsartikel (refereegranskat)abstract
- Mass, heat and momentum transport processes are strongly coupled with catalytic chemical reactions in a methane steam reforming duct. In this paper, a three-dimensional calculation method is developed to simulate and analyze reforming reactions of methane, and the effects on various transport processes in a steam reforming duct. The results show that the design and operating parameters grouped as characteristic ratios have significant effects on the transport phenomena
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