Turbulence of melt-blowing airflow field: Comparison of a convergent jet and a typical free jet

The turbulent characteristics of the melt-blowing convergent jet and a typical free jet are compared based on the data obtained from hot-wire measurements. For the first time, the effects of the impingement, which is created by the two jet branches issuing from a convergent jet nozzle, on the turbulence intensity, Reynolds shear stress, and power spectral density of turbulent velocities, are investigated. The results show that the impingement leads to greater and faster spread of the additional turbulent shear stress and a larger portion of higher frequency components. The characteristics of the dual-impinging jets under the slot-die nozzle provide the possibility of controlling the melt-blowing airflow field.