1. Effects of thermal expansion on Taylor dispersion-controlled diffusion flames
- Author
-
Prabakaran Rajamanickam and Adam D. Weiss
- Subjects
Materials science ,General Chemical Engineering ,Taylor dispersion ,Fluid Dynamics (physics.flu-dyn) ,FOS: Physical sciences ,General Physics and Astronomy ,Energy Engineering and Power Technology ,Physics - Fluid Dynamics ,General Chemistry ,Mechanics ,Hagen–Poiseuille equation ,Thermal expansion ,Poiseuille flow ,Pipe flow ,Physics::Fluid Dynamics ,Fuel Technology ,Modeling and Simulation ,non-unity Lewis number ,Diffusion (business) ,Burke–Schumann flame ,Mixing (physics) ,thermal expansion ,Gas expansion - Abstract
A theoretical analysis is developed to investigate the effects of gas expansion due to heat release on unsteady diffusion flames evolving in a pipe flow in which the mixing of reactants is controlled by Taylor's dispersion processes thereby extending a previously developed theory based on the thermo-diffusive model. It is first shown that at times larger than radial diffusion times, the pressure gradient induced by the gas expansion is, in the first approximation, small in comparison with the prevailing pressure gradient driving the flow, indicating that corrections to the background velocity profile are small. The corrections to the velocity components along with the leading-order mixing variables such as the concentrations, temperature and density are solved for a Burke–Schumann flame. Due to the dependence of the effective Taylor diffusion coefficients on the gas density, quantitative and sometimes qualitative departures in predictions from the thermo-diffusive model are observed.
- Published
- 2021