Optimization analysis of combing box for air yarn based on computational fluid dynamics

Abstract

Conventional single card air yarn units create flow vortices in the carding box that affect the fiber structure and thus the yarn performance. Key parameters for airflow characteristics include geometry and spinning parameters (Such as the length of the nozzle, the width of the inlet and outlet, the speed and diameter of the felting roller). This paper proposes to improve the transport channel to reduce eddy currents in the upflow region and to analyze airflow fields using fluid knowledge. This paper examines three designs: a bypass circular channel entrance for air supply, rounded corners at the bottom right in the conveyor channel and combining both modifications. According to the analysis, a nozzle inlet/outlet ratio between 0.5 and 1 gives the lowest swirl and the highest mass flow. Considering the yarn characteristics and the system production efficiency, it is ideal when the barbed roll speed is 8000 rpm and the diameter is about 30 mm. It is possible to dissipate the vortices for three methods.