Experimental and numerical investigation of Cross-Flow nebulizer for developing optimized suction pressure

Abstract

A pneumatic nebulizer, a device that supplies the spray of the mist of liquid using pressurized air. A cross-flow nebulizer is a very popular pneumatic nebulizer due to its robust design. It consists of a partially filled liquid vessel and an orifice-capillary assembly through which pressurized gas is supplied. When air passes through the orifice, low pressure develops in the capillary, leading to the free aspiration of liquid in the nebulizer. It is expected that nebulizers must have controllable and reproducible output performance. In this paper, an experimental and numerical investigation of the orifice-capillary assembly of a nebulizer is presented. A cross-flow nebulizer is fabricated using 3D printing. In the experimental study, the vacuum pressure and the gas velocity developed in the cross-flow nebulizer are recorded. The steady-state numerical analysis of the three-dimensional nebulizer using Ansys Fluent R19 software and gas–liquid interaction inside the nebulizer is studied. The effect of supply inlet pressure on the performance of the nebulizer, i.e. generating the vacuum at capillary, is presented. It has been observed that for a certain range, with an increase in supply inlet air pressure till 2 bar, the vacuum developed inside the nebulizer, i.e. in the liquid capillary of the nebulizer increase. But with a further increase in supply inlet air pressure, a negative relationship is seen. Hence for a given geometry, there exists an optimized orifice-capillary assembly configuration.