Use of the one-dimensional t-burner to study oscillatory combustion

This paper desciibes a simple buiner used foi the study of oscillatoiy combustion and the icsults obtained therefrom. The burner, commonly called the T-burner, consists of sidevented cylindrical steel chamber in the ends of which piopellant disks are burned If the propellant combustion spontaneously geneiates piessure oscillations, use is made of the over-all one-dimensional acoustic behavior in the system to characteiize the transient combustion of the piopellant The important vaiiables used in the chaiacterization are the growth late of the oscillations and their decay rate following the consumption of the piopellant A desciiption is given of the several types of investigations in which the T-buinei is the primaiy research tool These investigations concern the response function of the combustion zone, the effect of normal pressure peituibations upon the average burning rate of the propellant, the participation of the piopellant in the acoustic motion of the system, the mechanism by which aluminum supiesses oscillatoiy combustion, and the influence of piopellant composition upon the icsponse function of the combustion zone The latter two desciiptions are given in some detail Nomenclature c = speed of sound in the combustion gas f = frequency of the oscillations I = length of the gas column in the T-burner HD = number of particles per unit volume of combustion gas with diameter D pm = amplitude of the pressure oscillations pQ = amplitude of the pressure oscillations at an arbitrary zero time p = mean chamber pressure r = burning rate of the propellant R = radius of the particle in the combustion gas t = time Y = speed with which the gas leaves the combustion zone Y = real part of the specific acoustic admittance of the combustion zone Z = (2-jrfRz/2v)112 ag = exponential constant that describes the growth of the oscillations ad — exponential constant that describes the decay of the oscillations exa = reduction in ag which is caused by the presence of aluminum or alumina in the propellant 7 = ratio of the heat capacities of the combustion gas n = amplitude of the fractional mass flow rate perturbation of the mass leaving the combustion zone e = amplitude of the fractional pressure perturbation which causes /z a = amplitude of the fractional density pertuibation accompanying e p = density of the combustion gas p = density of the propellant pp = density of the particles in the combustion gas v = kinematic viscosity of the combustion gas 5 = P/PP