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Study on Compact Mechanism of Pneumatic Compact Spinning with Lattice Apron

Author: YangJianPing
Tutor: WangJun；HuangXiuBao
School: Donghua University
Course: Textile Engineering
Keywords: Spinning Grid circle Negative pressure Agglomeration Mechanism Semi - free end twisting Additional twist Twist transfer length Arc -shaped gathering slot
CLC: TS104.1
Type: PhD thesis
Year: 2011
Downloads: 48
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Abstract

Spinning is a new technology developed on the basis of the traditional ring spinning in nearly a decade. Gathering yarn while maintaining the inherent advantages of ring yarn, but also significantly improved yarn quality and grades, especially in yarn hairiness and strength, and thus the technology at home and abroad rapid promotion. The basic spinning preliminary studies focus on the contrast of yarn structure, yarn performance testing, spinning process optimization and fiber inside and outside the transfer, Agglomeration Mechanism relatively small aggregates by studying fiber kinematic and dynamic school model, in-depth analysis of the fiber assembly in the gathering area of ??the agglomeration process, further theoretically fiber assembly in the gathering area gathering mechanism, not only has a good theoretical significance, but also has application value, able to stacking mechanism design optimized to provide the basis. This article is based on the grid turn negative pressure compact spinning system research, the main contents include the following five areas: (1) linear cluster chute gathering area to be additional twist preliminary study based on production practices and research group research, given the definition of gathering additional twist; through high-speed photography to get the image spinning gathering area shall then be able to show a straight gathering chute gathering area shall exist Volume twist phenomenon; followed by spinning test confirmed the twist the existence and true twist; proposed new \followed by a gathering chute straight kinematics analysis, the establishment of a gathering area shall bar the additional twist model; final spinning test, to verify the correctness of the model. (2) straight passes required to strip twist and twist transfer length model first study linear clustering the chute twist pass proposed transfer length to characterize the effect of gathering additional twist; followed by mechanical analysis, gathering skewed gathering area establish gather additional twist transfer the length differential equations model; then using MATLAB programming, simulation discuss gather be Radius, gathering the required negative friction coefficient, the gathering pipe gathering area of ??the radius of curvature, gathering chute inclination and gathering the grid circle pressure with the additional twist to pass the length of the relationship; the last long research gathering troughs theory design basis. (3) design the theory and practice of the arc-shaped cluster slot first analyze the problem of gathering chute linear spinning; Second design new clustering trough proposed to the arc-shaped instead of straight, can overcome gathering jaws exist yarn movement speed direction mutations; mechanical analysis method to establish the arc-shaped gathering chute shall bar the additional twist differential equations model; then using the fourth order Runge - Kutta methods, numerical analysis of the model, discuss the gathering to be radius, gathering to be with the grid circle friction coefficient, the gathering pipe gathering area of ??the radius of curvature, gathering arc groove curvature radius and gather negative pressure on the additional twist; final design and processing of the arc-shaped cluster slot, spinning test validation. (4) gathering area airflow field distribution model airflow field distribution in the gathering area of ??computational fluid dynamics (CFD) models and analysis. And using computational fluid dynamics software FLUENT numerical solution of air flow field calculation model created gathering area agglomeration area airflow characteristics; the research gathering area airflow distribution law and its gathering required role. (5) analysis and the twist factor to determine the existence of significant differences from the yarn diameter of the yarns and ring-spun yarn of the same linear density agglomeration, agglomeration yarn twist level, the investigate agglomeration yarn twist angle, twist and ring-spun yarn presence differences yarn twisting, and on this basis, the basis for selection of the gathering yarn twist factor. Through this modeling, solving, testing and analysis, the following conclusions: (1) linear cluster chute gathering area required additional twist through high-speed photography and spinning test confirmed the compact spinning process, gathering area shall bar there is an additional twist. Proposed new gathering area to Article half free end twisting model to explain the mechanism of the formation of additional twist. Be in the gathering area of ??the kinematics analysis, straight agglomeration slot gathering the required the additional twist mathematical model: of tw = sinβ/2πr, additional twist tw and agglomeration is required radius r and gathering chute angle β related. Through different linear density, the spinning of a different twist to the test, to verify its correctness, and reveal the reasons tilted straight gathering chute right. The results also show that the the linear clustering groove certain tilt angle is one of the necessary conditions for the gathering area required to strip to generate additional twist. (2) straight gathering chute gathering area shall twist transfer bar and twist transfer length model proposed gathering area shall the additional twist passed concept, with a gathering area shall bar pass additional twist length agglomeration effect characterization; mechanical analysis, gathering be additional twist transfer length model, the analytical solutions obtained: (?) show that the twist be pass length be radius r, s and gathering gathering with mesh circle friction factor μ, the gathering pipe gathering area radius of curvature R, gathering chute inclination β, gather negative pressure p and so on, and also to be related to the cross section of fibers number Nf and fiber of torsional stiffness KfGf of. On this basis, calculated by MATLAB programming, discussed the gathering to be radius r, gathering required friction coefficient μ between the grid circle, the the gathering pipe gathering area of ??the radius of curvature R, gathering chute angle β, to gather negative pressure p and The the gathering area be twist passed length s relationship. The simulation results show that the gathering pipe gathering area of ??the radius of curvature R of the gathering area passed be additional twist has little effect on the length of s, gather the required radius r, gathering required friction coefficient μ between the grid circle gathering chute inclination β gather negative pressure p on the gathering area passed be additional twist the length s more significant gathering required radius r with the gathering negative pressure p between internal relations, pending further study. Through MATLAB programming 15.3tex gather 9.7tex cotton yarn, obtained additional twist to the transfer length is about 10 ~ 22mm, and verified by experiment a gathering area shall be the additional twist passed length model correctly straight gathering The long troughs design provides a theoretical basis. (3) design the theory and practice of the arc-shaped cluster slot according to the straight-line-shaped gathering spinning gathering jaws at the presence of the mutation in the direction of yarn movement speed, arc-shaped cluster slot design thinking. Mechanical analysis to establish the model of the arc-shaped cluster slot gathering be additional twist differential equations, that additional twist tw gathering required radius r, gather to be the the grid circle friction factor μ gather negative pressure p agglomeration tube gathering area of ??the radius of curvature R, the radius of curvature of the arc grooves R1 and the agglomeration tube cross-sectional shape and so on. Calculated by the numerical simulation of the model to discuss the need to gather radius r, gathering required grid circle friction factor μ gather negative pressure p, gather pipe gathering area of ??the radius of curvature R and the arc groove radius of curvature R1 additional twist the impact. The simulation results show that the The gathering pipe gathering area of ??the radius of curvature R little additional twist, other factors are more significant. The design and processing of the arc-shaped groove gathering tube and spinning test. The test results verify the the additional twist model is correct, that the gathering of the arc-shaped cluster slot spun yarn quality is better, can be applied to production practice. (4) gathering area of ??airflow field distribution models of the establishment and analysis of spinning gathering area, airflow from four weeks to gather slot convergence around on both sides in the gathering slot airflow gathering groove edge perpendicular to the direction of flow of the gathering slot; gathering above the pipe, the airflow from four weeks to gather groove aggregation, the closer the gathering slot, the higher the air velocity. This flow law makes airflow fiber be likely to shrink by a flat section into a circular cross-section, the agglomeration effect. In most areas of the gathering area of ??airflow static pressure value is closer to the external atmospheric pressure; hydrostatic value of the air flow decreases rapidly, to form a negative pressure area in the vicinity of the gathering groove, the closer the agglomeration groove and the center of internal flow hydrostatic The lower the value. The numerical simulation results show that both sides of the subject when straight gathering chute inclination change within a smaller range (0 ° -5.6 °) be more similar to the role of the gathering of the airflow, the gathering to be roughly along the groove center line of the gathering conveyor ; while with the agglomeration groove inclination angle is further increased, the required trend near to the right side of the gathering groove, when be role by gripping on both ends, and this trend will cause agglomeration shall bar around its own axis of the rolling . Pressure applied along the length direction of the gathering slot gathering area airflow required to strip certain fluctuations, fluctuation range is not large, indicating that in the fourth chapter of this article, Chapter gathering be additional twist theoretical transfer length and the additional twist model, the applied pressure of the airflow required article is a reasonable assumption is constant. Straight agglomeration slot inclination and gathering groove shape of the pressure exerted by the airflow required to strip is not significant, while the gathering slot width increases and agglomeration negative pressure will lead to the improvement of the pressure exerted by the airflow required to strip. (5) gathering yarn twist level analysis and twist factor determining the gathering yarn and ring yarn structure different twist level of characterization is different. Ring yarn twist factor generally does not apply to the gathering yarn. Agglomeration close arrangement of fibers in the yarn within the yarn of the accumulation of the same line density as compared with the ring-spun yarn, the volume density of 15 to 30% increase, measure the degree of agglomeration yarn twisting necessary to consider the twist angle, twist and the yarn diameter, relationship. Agglomeration yarn twist factor selection can be determined depending on the yarn strength, can generally be reduced by about 10 ~ 15% than the twist coefficient of the ring-spun yarn of the same linear density. On the grid turn negative pressure compact spinning system, the coupling between the fiber assembly with grid circle, mechanical systems and gathering airflow field is more complicated. Agglomeration Mechanism in the research work of more than five a certain role, a role in guiding further optimize the the gathering device's design, and enhance the effect of gathering, gathering yarn quality and promote the development of compact spinning technology.

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CLC: > Industrial Technology > Light industry,handicrafts > Textile industry,dyeing and finishing industry > General issues > Spinning theories and spinning process > Theory and Design
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