scholarly journals Investigation on the Dynamic Behavior of the Fiber in the Vortex Spinning Nozzle and Effects of Some Nozzle Structure Parameters

2011 ◽  
Vol 6 (2) ◽  
pp. 155892501100600
Author(s):  
Zeguang Pei ◽  
Chongwen Yu
Keyword(s):  
Dynamic Behavior ◽  
Textile Industry ◽  
High Speed ◽  
Orifice Diameter ◽  
Structure Parameters ◽  
Fiber Wall ◽  
Spun Yarn ◽  
Yarn Tenacity ◽  
Nozzle Inlet ◽  
Nozzle Structure

Vortex spinning, which adopts high speed airflow to insert twist into the yarn, is one of the most promising technological innovations in the textile industry. In vortex spinning, the dynamic behavior of the fiber inside the nozzle, which involves fiber-airflow interaction and fiber-wall contact, plays an important role in the twist insertion process. This paper investigates the airflow characteristics and the fiber dynamic behavior inside the vortex spinning nozzle via a two-dimensional numerical model with the fiber-airflow interaction and fiber-wall contact included. The fiber is assumed to be isotropic, elastic material. The airflow inside the nozzle is assumed to be turbulent, viscous and incompressible. The numerical results show that two vortices with momentarily changed sizes are created upstream of the jet orifice outlets. The imbalance of the pressure around the fiber causes the fiber to move and deform. The trailing end of the fiber rotates with wave shape within the nozzle chamber for several periods to insert twist into the yarn. Based on the model, the effects of three nozzle structure parameters – the jet orifice angle, jet orifice diameter, distance between the nozzle inlet and the hollow spindle, on the dynamic behavior of the fiber, and in turn, the yarn structure and tensile property are investigated. The results show that the appropriate jet orifice angle for obtaining the best yarn tenacity is 70°. The optimal jet orifice diameter is 0.4 mm. The spun yarn has the highest tenacity when the distance between the nozzle inlet and the hollow spindle is 14 mm.

Reducing yarn hairiness in ring spinning by an agent-aided system

2019 ◽  
Vol 89 (21-22) ◽  
pp. 4438-4451 ◽  
Author(s):  
Peiying Li ◽  
Mingrui Guo ◽  
Fengxin Sun ◽  
Weidong Gao
Keyword(s):  
Textile Industry ◽  
Speed Ratio ◽  
Rotating Speed ◽  
Comprehensive Properties ◽  
Spun Yarn ◽  
Spun Yarns ◽  
Ring Spun Yarn ◽  
Yarn Hairiness ◽  
Yarn Tenacity

An agent-aided system (AAS) for improving comprehensive properties of ring spun yarns with the aid of viscosity and surface tension of the agent is reported in this paper. The mechanism of the humidification and friction process of the AAS was investigated, and related experiments were also carried out to verify the mechanism of analysis. The results confirm that the AAS can attach the fiber ends protruding out of a yarn body on the yarn surface and assist in twisting the fiber ends back into the interior of the yarn body, resulting in a significant reduction of the modified ring spun yarn hairiness. Moreover, the yarn hairiness is prominently reduced after the winding process. The experimental results also show that a speed ratio of 1.3 between the rotating speed of the cylinder and the output speed of the yarn leads to the greatest extent of harmful hairiness reduction (34%), which also corresponds to optimal modified yarn tenacity. Meanwhile, the modified ring spun yarns show a tight and smooth appearance, and the yarn evenness has no deterioration. In addition, the AAS is applicable to both cotton and viscose yarns with different yarn counts. Therefore, the AAS can potentially be used to reduce yarn hairiness for ring spun yarns and enhance the quality of ring spun yarns in the textile industry.

Comparison of Yarn Tenacity Data Obtained using the Uster Tensorapid, Dynamat II, and Scott Skein Testers

1992 ◽  
Vol 62 (3) ◽  
pp. 175-184 ◽  
Author(s):  
Lloyd B. De Luca ◽  
Devron P. Thibodeaux
Keyword(s):  
Tensile Test ◽  
Fiber Length ◽  
High Speed ◽  
Test Results ◽  
Slow Speed ◽  
Spun Yarn ◽  
Ring Spun Yarn ◽  
Tensile Data ◽  
Yarn Tenacity ◽  
One Machine

High speed yarn tensile testing machines increase production of yarn tensile data, but no comparisons with data from older, slow speed testing machines have been successful in determining whether these machines produce the same results. This work compares yarn tenacity data from three different machines. A family of five ring spun yarn sizes, each with five different twist factors, covers the entire range of spinning parameters for staple fibers. A new method used to analyze yarn data to determine the number of broken fibers and the effective fiber length acting in each yarn converts yarn tenacity into tenacity per broken fiber per effective fiber length. Converted yarn data from each machine show the effects of the time-to-break on tenacity and how the single strand yarn tensile test differs from one machine to another and with skein tensile test results.

Ball bearing turbocharger vibration management: application on high speed balancer

2020 ◽  
Vol 21 (6) ◽  
pp. 619
Author(s):  
Kostandin Gjika ◽  
Antoine Costeux ◽  
Gerry LaRue ◽  
John Wilson
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Ball Bearing ◽  
Squeeze Film ◽  
Design And Technology ◽  
Squeeze Film Damper ◽  
Damping Coefficients ◽  
Bearing Loads ◽  
Stiffness And Damping

Today's modern internal combustion engines are increasingly focused on downsizing, high fuel efficiency and low emissions, which requires appropriate design and technology of turbocharger bearing systems. Automotive turbochargers operate faster and with strong engine excitation; vibration management is becoming a challenge and manufacturers are increasingly focusing on the design of low vibration and high-performance balancing technology. This paper discusses the synchronous vibration management of the ball bearing cartridge turbocharger on high-speed balancer and it is a continuation of papers [1–3]. In a first step, the synchronous rotordynamics behavior is identified. A prediction code is developed to calculate the static and dynamic performance of “ball bearing cartridge-squeeze film damper”. The dynamic behavior of balls is modeled by a spring with stiffness calculated from Tedric Harris formulas and the damping is considered null. The squeeze film damper model is derived from the Osborne Reynolds equation for incompressible and synchronous fluid loading; the stiffness and damping coefficients are calculated assuming that the bearing is infinitely short, and the oil film pressure is modeled as a cavitated π film model. The stiffness and damping coefficients are integrated on a rotordynamics code and the bearing loads are calculated by converging with the bearing eccentricity ratio. In a second step, a finite element structural dynamics model is built for the system “turbocharger housing-high speed balancer fixture” and validated by experimental frequency response functions. In the last step, the rotating dynamic bearing loads on the squeeze film damper are coupled with transfer functions and the vibration on the housings is predicted. The vibration response under single and multi-plane unbalances correlates very well with test data from turbocharger unbalance masters. The prediction model allows a thorough understanding of ball bearing turbocharger vibration on a high speed balancer, thus optimizing the dynamic behavior of the “turbocharger-high speed balancer” structural system for better rotordynamics performance identification and selection of the appropriate balancing process at the development stage of the turbocharger.

High-Speed Atomic Force Microscopy for Studying the Dynamic Behavior of Protein Molecules at Work

2006 ◽  
Vol 45 (3B) ◽  
pp. 1897-1903 ◽  
Author(s):  
Toshio Ando ◽  
Takayuki Uchihashi ◽  
Noriyuki Kodera ◽  
Atsushi Miyagi ◽  
Ryo Nakakita ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Dynamic Behavior ◽  
High Speed ◽  
Force Microscopy ◽  
Atomic Force ◽  
Protein Molecules

Three Practical Examples of Magnetic Bearing Control Design Using a Modern Tool

2002 ◽  
Vol 124 (4) ◽  
pp. 1025-1031 ◽  
Author(s):  
M. Spirig ◽  
J. Schmied ◽  
P. Jenckel ◽  
U. Kanne
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Control Design ◽  
Industrial Applications ◽  
Magnetic Bearing ◽  
Engineering Practice ◽  
Digital Implementation ◽  
Bearing Characteristic ◽  
Multistage Centrifugal Compressor ◽  
Modern Tool

The use of magnetic bearing in industrial applications has increased due to their unique properties. Nowadays efficiency and predictability in handling rotors on magnetic bearings is asked with the same standard as conventional rotors on oil or roller bearings. First of all one must be aware of the special technical properties of magnetic bearing designs. The dynamic behavior of the rotor combined with requirements of the application define the desired bearing characteristic. With modern tools covering the mechanical aspects as well as the electronic controllers and their digital implementation on a DSP, these properties can be designed. However, despite the use of such efficient tools engineering practice is needed. Therefore this paper summarizes the major steps in the control design process of industrial applications. Three rotors supported on magnetic bearing with their specific dynamic behavior are presented: a very small high speed spindle (120,000 rpm); a small industrial turbo molecular pump rotor (36,000 rpm); and a large multistage centrifugal compressor (600 to 6300 rmp). The results of the analyses and their experimental verification are given.

scholarly journals World Experience in Creating Mathematical Models of Air Springs: Advantages and Disadvantages

2021 ◽  
pp. 25-42
Author(s):  
A. Y Kuzyshyn ◽  
S. A Kostritsia ◽  
Yu. H Sobolevska ◽  
А. V Batih
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Mathematical Models ◽  
Dynamic Behavior ◽  
High Speed ◽  
Vertical Direction ◽  
Rolling Stock ◽  
Air Spring ◽  
Advantages And Disadvantages ◽  
Mechanical Models

Purpose. Taking into account the production and commissioning of modern high-speed rolling stock, the authors are aimed to analyze the currently created mathematical models describing the dynamic behavior of the air spring, systematize them and consider the advantages and disadvantages of each model type. Methodology. For the analysis, a comparative chronological method was used, which makes it possible to trace the development of several points of view, concepts, theories. In accordance with the adopted decision equations, the existing models of air springs were divided into three groups: mechanical, thermodynamic and finite-elements. When analyzing mathematical models, the influence of a number of parameters on the dynamic behavior of the air spring, such as disturbing force frequency, heat transfer, nonlinear characteristics of materials, the shape of the membrane, etc., was considered. Findings. A feature of mechanical models is the determination of input parameters based on the analysis of experimental results, requires access to complex measuring equipment and must be performed for each new model of an air spring separately. Unlike mechanical models, which allow taking into account the damping effect of an air spring in the horizontal and vertical direction, thermodynamic models are mainly focused on studying the dynamic behavior of an air spring in the vertical direction. The use of the finite element method makes it possible to most accurately reproduce the dynamic behavior of an air spring, however, it requires significant expenditures of time and effort to create a finite element model and perform calculations. Originality. Mathematical models of the dynamic behavior of an air spring are systematized, and the importance of their study in conjunction with a spatial mathematical model of high-speed rolling stock is emphasized. Practical value. The analysis of the mathematical models of the dynamic behavior of the air spring shows the ways of their further improvement, indicates the possibility of their use in the spatial mathematical model of the rolling stock in accordance with the tasks set. It will allow, even at the design stage of high-speed rolling stock, to evaluate its dynamic characteristic and traffic safety indicators when interacting with a railway track.

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