Flow Characteristics in an Air Jet Loom with a Modified Reed and Auxiliary Nozzles

Abstract

In this basic research for improving the performance of main nozzle of an air jet loom with a modified reed and auxiliary nozzles, the relation between the length of an acceleration tube and jet flow characteristics for 2∼6kgf/cm2 tank pressures has been eamined within both subsonic and supersonic regions of jet speed. Further, the weft drag force by the main nozzle has been measured.The results are as follows : (1) The distributions of jet speed in the subsonic flow region are little affected by acceleration tube length of the nozzle (2) In the supersonic flow region, some effects of the tube length are founded. For nozzles with the accerelation tube length L≥70mm, expansion waves are generated at the nozzle exit, on the other hand, for a nozzle with L= 50mm, compression shock waves occur. (3) In the supersonic flow region, the generation of expansion waves for nozzles withL=70mm causes an abrupt increase in jet diameter and a reduction of the flow speed. However for a nozzle with L= 50mm, significant changes in jet diameter and speed can not be observed owing to the genenration of compression shock waves. (4) The weft drag force is strongly affected by the flow through an accerelation tube. The drag force is smaller as the accerelation tube length becomes shorter.