Experimental study of jet mixing mechanisms in a model secondary combustor

A schlieren photographic study of flow characteristics in a secondary combustor of a rocket/ramjet with side intakes has been made with a two-dimensiona l mixing duct. The experiments were conducted by means of airflows, a primary jet, and two secondary crossflows up to a Reynolds number of 10 6. The flow patterns in the early stage of the mixing processes were observed under a variety of conditions. Effects of a bluff body on the mixing processes were also examined. The results show that the mixing rate seems strongly dependent on the interaction of the Coanda-type vibrating primary jet and the secondary flows acting as its stabilizer. It was seen that the bluff body of the present study can delay the mixing rate depending on the flow condition. Nomenclature A b f F H k L M n P = cross-sectional area = bluff-body height —area ratio, As/Am = area ratio, Ab/As = height of cross section of mixing duct = specific heat ratio = size of recirculation zone = Mach number = weight flow rate ratio, Wal Wp - static pressure = total pressure = temperature = total temperature = weight flow rate = axial distance from primary nozzle