An Experimental Study of Nozzle Geometry Effect on Mixing Characteristics of Two Different Twin Jets

This experimental work investigates the effect of circular nozzle with non-circular nozzle in a flow-field issuing from circle-ellipse twin jet and the same is compared with circular twin jet for Mach numbers 0.4 and 0.6. For the two twin jet cases, the jets emanated from both nozzles of the twin jets are free jets and had the identical Mach number. In both twin jet cases, for all the Mach numbers, the nozzle spacing (S) is 20 mm. The exit area is 78.5 mm² which is same for all the nozzles. The ratio of nozzle spacing to nozzle exit diameter (S/D) for both cases was kept as 2. The results from the radial (Y) direction and shadowgraph pictures indicate that the circle-ellipse twin jet show better mixing enhancement as the entrainment between the ambient fluid and the jets from the nozzles is more. It is also observed that both the nozzle exit Mach number and nozzle geometry strongly influences the mixing of the two jets.