Investigation of the fiber packing density in a unidirectional composite

1977 ◽  
Vol 12 (3) ◽  
pp. 493-495 ◽  
Author(s):  
M. Z. Kanovich ◽  
M. A. Koltunov ◽  
S. L. Roginskii
Keyword(s):  
Packing Density ◽  
Unidirectional Composite ◽  
Fiber Packing Density

Numerical Study of Boiler Feed Water Deoxygenation Using Hollow Fiber Membrane Contactor

2013 ◽  
Vol 561 ◽  
pp. 206-211
Author(s):  
Xiao Guang Zhang ◽  
Shi Gang Wang
Keyword(s):  
Dissolved Oxygen ◽  
Sherwood Number ◽  
Hollow Fiber ◽  
Packing Density ◽  
Hollow Fiber Membrane ◽  
Power Industry ◽  
Feed Water ◽  
Membrane Contactor ◽  
Fiber Membrane ◽  
Fiber Packing Density

Removal of dissolved oxygen from feed water is a necessary process in power industry. The hollow fiber membrane contactor is more efficient and pollution-free compared with some traditional methods. In this paper, hollow fiber is modeled by random distribution, and Gaussian function N(R, sigma) was used to model the polydisperse out radii of hollow fiber. This paper discussed the influence of different sigma on mass transfer coefficient with fiber packing density ranging from 0.1 to 0.4. It was found that, the effect of different sigma on the logarithmic mean Sherwood number decreased with increasing fiber packing density. When the packing density increased to 0.4, the removal of dissolved oxygen could meet the requirement of power industry, no matter how much value the sigma was. With the sigma increasing, the deviation of max and min Sherwood number from the average value increased gradually, except when the sigma was 0.05. This paper deduces there is a best value of sigma for membrane contactor when the fiber distribution is randomly distributed.

Compression and Packing Density of Fibrous Assemblies

1997 ◽  
Vol 67 (2) ◽  
pp. 123-130 ◽  
Author(s):  
Bohuslav Neckář
Keyword(s):  
Experimental Work ◽  
Packing Density ◽  
Deformation Equation ◽  
Fiber Packing Density ◽  
Fibrous Assemblies ◽  
Theoretical Results

This paper presents a generalization of the unidimensional deformation equation based on the van Wyk theory. The derivation considers the effect of uncompressed areas between contacting fibers. Theoretical results are verified by the experimental work of Baljasov. The solution is extended to cover bidimensional deformation of an oriented fibrous assembly. The work also proves the importance of using fiber packing density as the argument in the compression equation.

Optimal Fiber Spacing in Externally Pressurized Hollow Fiber Module for Solid Liquid Separation

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1245-1254 ◽  
Author(s):  
W. Y. Kiat ◽  
K. Yamamoto ◽  
S. Ohgaki
Keyword(s):  
Activated Sludge ◽  
Flow Velocity ◽  
Hollow Fiber ◽  
Packing Density ◽  
Cross Flow ◽  
Kaolin Clay ◽  
Flux Decline ◽  
Fiber Packing Density ◽  
Cross Flow Velocity ◽  
Clay Suspensions

Flux decline and clogging mechanism in hollow fiber bundle by activated sludge and kaolin clay suspensions were investigated experimentally. Filtration characteristics of hollow fiber bundles consisting of 10 fiber threads but different in packing density were observed. The main reason for severe flux decline was due to the accumulation of particles at the space in between fibers. The results showed that there was no particle accumulation when fiber packing density β was lower than a critical value βa. Maximum filtration flux and maximum membrane productivity Q/Vr,which is defined as the filtration rate per unit volume of bundle, were obtained below and at this point, respectively. When fiber packing density β was increased, accumulation of particles happened and flux declined rapidly to a minimum, then increased to a maximum and then decreased when surface clogging predominated in the case of activated sludge filtration, but remained almost constant for the case of kaolin clay suspensions. The critical point where accumulation of particles started was related to cross flow velocity. The higher the cross flow velocity, the higher the value of βa obtained.

Study of fiber packing density of lyocell ring‐spun yarns

2011 ◽  
Vol 102 (5) ◽  
pp. 389-394 ◽  
Author(s):  
Maryam Salehi ◽  
Majid Safar Johari
Keyword(s):  
Packing Density ◽  
Fiber Packing Density ◽  
Spun Yarns

Internal Mechanics of Twisted Yarn

1976 ◽  
Vol 46 (8) ◽  
pp. 545-562 ◽  
Author(s):  
Bohuslav Neckář
Keyword(s):  
Differential Equation ◽  
Theoretical Model ◽  
Packing Density ◽  
Method Of Calculation ◽  
Yarn Diameter ◽  
Fiber Packing Density ◽  
Cotton Yarns ◽  
Strain Relationship ◽  
Mathematical Evaluation

Part I: Theoretical Model The equilibrium of the yarn element is defined on the basis of a cylindrical model of yarn formation. The fibrous system is considered a continuum. The stress-strain relationship is solved for the element of this fibrous continuum. A mathematical model is proposed which is based on the idea of effective elastic bonds including nonlinearity and finite strains. Through substitution of this model in a differential equation of equilibrium, a differential equation is found which can be solved numerically. Also, the effect of fiber migration is taken partly into consideration. A method of calculation is deduced for the course of the radial fiber packing density. Part II: Application A new method of experimental determination of the course of the fiber packing density is described. The method is based on mathematical evaluation of tracer fibers from photographs produced on the OMEST Tester. A modified evaluation of experimentally determined yarn diameters is proposed. Results obtained with carded cotton yarns are specified. The theoretical model is processed numerically. The input parameters of the numerical solution are discussed. Theoretical results are compared with the results of the fiber packing density and yarn diameter measurements. The findings are discussed from the viewpoint of the physical aspects of the internal mechanics of yarn.

Maximum Fiber-Packing Density in Electrostatic Flocking

1981 ◽  
Vol 51 (12) ◽  
pp. 768-773 ◽  
Author(s):  
V.A. Semenov ◽  
S.P. Hersh ◽  
B.S. Gupta
Keyword(s):  
Packing Density ◽  
Fiber Packing Density

Fiber packing density in the cross-section of low torque ring spun yarn

2016 ◽  
Vol 88 (2) ◽  
pp. 191-202 ◽  
Author(s):  
Ying Guo ◽  
Xiaoming Tao
Keyword(s):  
Cross Section ◽  
Packing Density ◽  
Compact Structure ◽  
Axial Tension ◽  
Spun Yarn ◽  
Fiber Packing Density ◽  
Spun Yarns ◽  
Ring Spun Yarn ◽  
The Cross ◽  
Low Torque

Fiber packing density in the yarn cross-section is one of the major parameters that reflect the yarn internal structure and its final properties. Taking the novel low torque ring spun yarn as the object, this work studied the fiber packing density of low torque ring spun yarns and conventional ring spun yarns under various axial tensions. With the increase of tension, the change of fiber packing state in low torque ring spun yarns and conventional ring spun yarns was compared qualitatively. In this study, fiber distribution in the cross-section of both Tencel yarns and wool yarns was carried out. The results show that, under the same axial tension, the packing density of fibers of low torque ring spun yarn is much higher than that of conventional ring spun yarn. The axial tension has greater influence on the fiber packing density for the conventional ring spun yarn. From the experimental results, in low torque Tencel yarn, the fiber packing density nearly reaches 0.9, which is the maximum value for close-packed yarn. Due to different fiber properties and yarn structure, it is difficult to form a close packing for fibers in low torque ring wool yarns. The current results indicate that low torque ring spun yarn has a more compact structure than conventional ring spun yarn. Compared with conventional ring spun yarns with the same count and twist levels, in low torque ring spun yarns, more fibers contribute to the yarn breaking strength.

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