A chemical-diffusive model for simulating detonative combustion with constrained detonation cell sizes

摘要

This paper presents a way that improves the use of the chemical-diffusive model (CDM) in a fluid dynamicscode to simulate the multidimensional structure of propagating gaseous detonation waves. In theCDM, a set of critical parameters is calibrated and used in a reaction rate that converts fuel to product.The parameters are currently chosen to reproduce properties of a one-dimensional standard laminarflame and the Zel’dovich-Neumann-D?ring (ZND) detonation when a reaction is incorporated in the compressibleNavier-Stokes equations. The ability of the CDM to compute cellular structure of stoichiometrichydrogen-air detonations is compared to results obtained using a detailed chemistry model and experimentalmeasurements. Both the CDM and the detailed chemical model produce very similar detonationcells in terms of shape and size, but these cells are smaller than experimental values by a factor of twoto three. In a new approach, the CDM is calibrated using experimental detonation cell data. A relationbetween the effective activation energy and the ratio of the detonation cell size to the ZND half-reactiondistance is used to incorporate known properties of detonation and detonation cells in the CDM optimizationprocedure. Numerical simulations using the new CDM parameters reproduce detonation cells ofthe same size and shape as experimental measurement.