Airflow simulation in nozzle for hairiness reduction of ring spun yarns. Part I: influence of airflow direction, nozzle distance, and air pressure

In order to explore the differences between conventional and dual-feed-opening rotor spinning units (RSUs), this work compares the airflow characteristics of two RSU models utilizing a computational fluid dynamics simulation model with the accuracy verified by airflow behavior observation and air pressure measurement. The effect of two different opening roller speeds on the airflow field distribution of a dual-feed-opening model is also investigated. In addition, the yarn properties of six pure and blended yarns corresponding to the two RSU models are evaluated. The results reveal that the distributions of airflow velocity vector and air pressure in the two RSU models show a strong similarity under the same boundary conditions. However, the dual-feed-opening model possesses a centrosymmetric and more balanced airflow field distribution compared to the conventional model. In addition, the dual-feed-opening yarns show a superior performance in comparison to the conventional yarns. Furthermore, for the dual-feed-opening model, there are equivalent contributions of two separated opening and fiber transmission systems to the airflow field distribution and yarn formation. Compared to the configuration with the same two opening roller speeds, the dual-feed-opening model configured with two different opening roller speeds obtains an improved blended yarn performance with having few effects on the airflow characteristics. This strength of the dual-feed-opening RSU could facilitate the production of blended and fancy yarns employing the fibers with diverse properties. This study could provide some guidelines for the manufacture of rotor-spun yarns and the future design of RSUs.

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20—THE INFLUENCE OF THE AIR PRESSURE AT THE ROTOR-CLEANING DEVICE OF ROTOR-SPINNING MACHINES ON THE PROPERTIES OF COTTON OPEN-END-SPUN YARNS

Journal of the Textile Institute ◽

10.1080/00405008508658941 ◽

1985 ◽

Vol 76 (5) ◽

pp. 301-313 ◽

Cited By ~ 1

Author(s):

A. Barella ◽

A. M. Manich ◽

L. Castro ◽

Patricia N. Marino ◽

J. Carpintero

Keyword(s):

Air Pressure ◽

Rotor Spinning ◽

Spun Yarns ◽

Cleaning Device

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Air-Jet Texturing of Spun Cotton Yarns for Improved Comfort

Textile Research Journal ◽

10.1177/004051759206200106 ◽

1992 ◽

Vol 62 (1) ◽

pp. 40-43 ◽

Cited By ~ 3

Author(s):

J. Srinivasan ◽

A. K. Sengupta ◽

V. K. Kothari

Keyword(s):

Flexural Rigidity ◽

Twist Angle ◽

Air Pressure ◽

Air Jet ◽

Reduced Modulus ◽

Spun Yarns ◽

Cotton Yarns ◽

Structural Configurations

We have studied air-jet texturing of spun yarns with different structural configurations. After texturing, the yarns have improved bulk and reduced modulus and flexural rigidity, rendering them more suitable for improved comfort applications. Increased bulk after texturing is accompanied by reduced strength. We have observed that after air-jet texturing, certain structures such as carded ring spun yarns and Siro spun yarns possess a higher level of bulk compared to other structures. Rotor spun yarns have lower bulk after texturing because of their tripartite structure, twist angle variations, and the alternating Z and S helices in their fiber belts. Yarns with reinforced structures like composite spun, wrap spun, and rotor spun are able to withstand higher overfeed and air pressure during texturing.

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Signal Interpretation Considerations When Estimating Subglottal Pressure From Oral Air Pressure

Journal of Speech Language and Hearing Research ◽

10.1044/2018_jslhr-s-17-0432 ◽

2019 ◽

Vol 62 (5) ◽

pp. 1326-1337 ◽

Cited By ~ 2

Author(s):

Brittany L. Perrine ◽

Ronald C. Scherer ◽

Jason A. Whitfield

Keyword(s):

Standard Condition ◽

Word Production ◽

Air Pressure ◽

Pressure Waveform ◽

Pressure Measurements ◽

Air Leak ◽

Pressure Signal ◽

Adult Participants ◽

Syllable Repetition ◽

Subglottal Pressure

Purpose Oral air pressure measurements during lip occlusion for /pVpV/ syllable strings are used to estimate subglottal pressure during the vowel. Accuracy of this method relies on smoothly produced syllable repetitions. The purpose of this study was to investigate the oral air pressure waveform during the /p/ lip occlusions and propose physiological explanations for nonflat shapes. Method Ten adult participants were trained to produce the “standard condition” and were instructed to produce nonstandard tasks. Results from 8 participants are included. The standard condition required participants to produce /pːiːpːiː.../ syllables smoothly at approximately 1.5 syllables/s. The nonstandard tasks included an air leak between the lips, faster syllable repetition rates, an initial voiced consonant, and 2-syllable word productions. Results Eleven oral air pressure waveform shapes were identified during the lip occlusions, and plausible physiological explanations for each shape are provided based on the tasks in which they occurred. Training the use of the standard condition, the initial voice consonant condition, and the 2-syllable word production increased the likelihood of rectangular oral air pressure waveform shapes. Increasing the rate beyond 1.5 syllables/s improved the probability of producing rectangular oral air pressure signal shapes in some participants. Conclusions Visual and verbal feedback improved the likelihood of producing rectangular oral air pressure signal shapes. The physiological explanations of variations in the oral air pressure waveform shape may provide direction to the clinician or researcher when providing feedback to increase the accuracy of estimating subglottal pressure from oral air pressure.

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