Nonlinear evolution of 2D cellular lean hydrogen/air premixed flames with varying initial perturbations in the elevated pressure environment. (9th February 2017)

• Record Type: Journal Article
• Authors: Yu, J.F.; Yu, R.; Bai, X.S.; Sun, M.B.; Tan, J.G.
• Is Part Of: International journal of hydrogen energy. Volume 42:Number 6(2017)
• Page Start: 3790
• Page End: 3803
• Publication Date: 2017-02-09
• Subjects: Flame instability -- Premixed flames -- Nonlinear flame dynamics -- Initial perturbations -- Elevated pressure -- Numerical errors; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2016.07.059
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: This paper reports on studies of cellular instability of lean hydrogen/air laminar premixed flames with an equivalence ratio of 0.6 at a 5 atm and a 25 atm pressure. Numerical simulations employing a detailed chemical kinetics mechanism and detailed transport properties are carried out to simulate the initial linear growth of instability as well as the nonlinear evolution of flames. At the initial linear growth stage, the amplitude of the initial sinusoidal shaped flame front grows exponentially. Later on, in the nonlinear evolution stage the flame front develops into a cellular surface with wavelengths and amplitudes different from its initial ones. At higher pressures, hydrodynamic instability is enhanced, due to smaller flame thermal thickness; the flame fronts are more chaotic. Chaotic flame fronts are captured during the nonlinear evolution stage and it is shown that the evolution is very sensitive to initial perturbations. Two phenomena in the nonlinear evolution process are observed, mode-lock and preferential choice of modes. Both of these appear in connection with the initial disturbances to the flame front. Sensitivity of the numerical results to numerical schemes and the computational setups is examined. Highlights: Two phenomena, preferential choice of modes and mode-lock, were noted. After a sufficient flame evolution, k1 mode becomes the dominant one. With the pressure increased, the flame fronts become more chaotic. Higher order numerical schemes and sufficient resolution are preferred.