Injection characteristics of non-swirling and swirling annular liquid sheets

A simplified mathematical model, based on body-fitted coordinates, is formulated to study the evolution of non-swirling and swirling liquid sheets emanated from an annular nozzle in a quiescent surrounding medium. The model provides predictions of sheet trajectory, thickness, and velocity at various liquid mass flowrates and liquid-swirler angles. It is found that a non-swirling annular sheet converges towards its centreline and assumes a bell shape as it moves downstream from the nozzle. The bell radius and length are more pronounced at higher liquid mass flowrates. Both the thickness and the stream-wise velocity of the non-swirling annular sheet are reduced with an increase in mass flowrate. The introduction of swirl results in the formation of a diverging hollow-cone sheet. The hollow-cone divergence from its centreline is enhanced by an increase in liquid mass flowrate or liquid-swirler angle. The hollow-cone sheet radius, curvature, and stream-wise velocity increase, whereas its thickness is diminished as a result of increasing the mass flowrate or liquid-swirler angle. The tangential velocity is greater at higher mass flowrates or smaller liquid-swirler angles. The present results are compared with previous studies and conclusions are drawn.