The authors consider experimentally the pressure flow of the non-Newtonian fluids in an eccentric double walled tube with a rotating inner cylinder. Experiments are carried out to measure the pressure gradient, the angle of the secondary flow region and the presure distribution on the outer cylinder using aqueous solutions of hydroxy ethyle celluslose (HEC). Results are summarized as follows :
1) The flow rate was enhanced by the rotation of an inner cylinder. In the relation between the flow rates in the stationary (Q_S) and the rotationary (Q_R) condition, the difference in Q_R by each eccentricity increased with effect of the rotation against the axial velocity.
2) The angle of the secondary flow region increased with decreasing number of rotations and increasing press ure gradient.
3) The pressure distribution on an outer cylinder was affected by the axial flow and varied in the different manner by the ratio of radius and the eccentricity.
4) Experimental values agree well with the numerical results. Consequently the reliability of the numerical method in the previous paper was confirmed.

View full abstract

In the previous paper, the flying behaviour of the yarn conveyed with the flow of air in a curved yarn guide pipe was investigated for the pipes with several different radii of curvature. For the yarn guide pipe used in the knotting process of an automatic winder, it is required that a yarn retrieved by the suction nozzle is in duced swiftly and accurately to the knotter under the minimum driving power.
In the present paper, the effects of the coefficient of flow resistance due to the suction nozzle for retrieving the yarn end and the coefficient of discharge of the slit along the curved pipe axis on the inducement of a yarn are investigated by experimental and numerical analyses. The values of Q₁/Q₃, T_1u andL_u. are formulated as the function of f, c and R/r, where, Q₁ : flow rate at the upstream edge of curved pipe, Q3 : flow rate at the downstream edge of curved pipe, T_1u : yarn tension required to jump the yarn out of the yarn guide pipe, L_u : flying length of the yarn for yarn tension of T_1u, f : coefficient of flow resistance due to suction nozzle, c : coeffi cient of discharge of the slit. The results give some available suggestions for the optimum designing of yarn guide pipe.

View full abstract

To learn a systematic method for effective training of machine sewing, general charateristics of adult women operators by an electric sewing have been in vestigated. Adult women operators were asked to sew along straight or curved lines printed on pre pared papers under several conditions. The results obtained were as follows :
1) The deviation of stitched lines from predeter mined guide lines increases with the increase of the curvature of the guide line. In addition, the increasing rate of the deviation as a result of the increase of the stitching speed also increases in proportion to the curvature.
2) The phase lag of stitched lines from predeter mined guide lines when sewing along sinusoidal curve increases as the stitching speed increases.
3) The tracking ability of operators along predeter mined guide lines is proportinal to an accumulation of the experience they have already gained.
4) Sewing at high speed along sharp curve tends to cause an irregular stitch and indented stitch line.
5) The deviation increases as intervals between predetermined guide marks increase and it becomes more remarkable on curves than on straight lines.
6) While sewing along straight lines, if intervals between predetermined guide marks are long enough or if stitching lines are apart from guide lines, the deviation decreases as sewing speed in creases.
7) The sewing speed control is more difficult when stitching along curved lines than along straight lines.

View full abstract