Computational and experimental investigation of unsteady flowfield inside the Rijke tube.

摘要

Computational and experimental studies of the unsteady flowfield inside a Rijke tube have been conducted. The investigation was carried out in an attempt to explain the heat transfer mechanisms that cause the heat driven oscillations. Due to inherent model complexities, no direct attempt has been made in the past to approach this particular problem numerically. The current modeling employs unsteady, compressible, two-dimensional symmetric flow fields that incorporate heat addition and acoustic interactions. The study proposes a new theory that attributes unsteady heat transfer to a direct coupling between acoustic pressure and velocity. The new model is more general than previous semi-empirical models and is based on computational, experimental, and dimensional analyses. The phase lag between heat oscillations and pressure oscillations and the phase lead between heat oscillations and velocity oscillations are determined computationally to be 45;The coupling mechanism investigated in this work can be applicable to a variety of problems incorporating heat, pressure and velocity perturbations, including solid and hybrid rocket motors. It is very likely that the numerical code developed for this type of pulsed combustor be successfully used in other applications as well.