A three-dimensional computational fluid dynamics model is developed by software Fluent 6.2, to simulate the flow field inside the nozzle block of the Murata vortex spinning. The flowing state and the distribution law ...A three-dimensional computational fluid dynamics model is developed by software Fluent 6.2, to simulate the flow field inside the nozzle block of the Murata vortex spinning. The flowing state and the distribution law of static pressure and velocity are characterized and analyzed. The relationship between the flowing state and the structure of the vortex spun yarn is also discussed. The research results can enhance the understanding of the yarn formation principle from viewpoint of the airflow field law inside the nozzle block of Murata vortex spinning.展开更多
Based on the mechanical system of free-end fibers and the analysis of pulling free-end fibers out of the spun yarn during spinning,a low-fiber hollow spindle is designed and the air distribution of fluent field is sim...Based on the mechanical system of free-end fibers and the analysis of pulling free-end fibers out of the spun yarn during spinning,a low-fiber hollow spindle is designed and the air distribution of fluent field is simulated numerically. The negative pressure effect is much bigger at the top of low-fiber hollow spindle than that in Murata No.861,which is more conducive for single fiber to get into the channel of hollow spindle. The tangential velocity in 0-3 mm at the top of hollow spindle increases and the fluctuation of radial velocity is much stronger,which enhance the wrapping effect. In the addition,the distribution of axial velocity remains the same.展开更多
Particulate matter(PM)from high-temperature emissions like chemical plants,coal stoves and vehicle exhausts poses a gravel challenge to human health.To address this issue,researchers have explored vari-ous fiber filte...Particulate matter(PM)from high-temperature emissions like chemical plants,coal stoves and vehicle exhausts poses a gravel challenge to human health.To address this issue,researchers have explored vari-ous fiber filters,yet the bulk struggle to withstand high temperatures.In this study,mullite fiber sponges were developed utilizing low-cost materials and Kármán vortex solution blow spinning,using surfac-tants to improve the spinnability of the sol.Optimized sponges demonstrate ultralight(19 mg cm^(-3)),temperature-resistant reversible compressibility(50% strain)and a water contact angle of 135°.These sponges exhibited exceptional thermal insulation(thermal conductivity:0.0256 W m^(-1) K^(-1))and per-formed well in high-temperature air filtration.At 800℃,the mullite sponge with a base weight of 35 mg cm^(-2),achieved an average filtration efficiency of 98.18%and 99.57% for PM_(2.5) and PM_(2.5-10),respectively,with a quality value of 0.98 Pa^(-1) at a wind speed of 4 cm s^(-1).This low-cost mullite fiber sponge offers a promising avenue for designing high-performance filtration materials.展开更多
基金This project is supported by the National Natural Science Foundation of China,under grant No.10872047.
文摘A three-dimensional computational fluid dynamics model is developed by software Fluent 6.2, to simulate the flow field inside the nozzle block of the Murata vortex spinning. The flowing state and the distribution law of static pressure and velocity are characterized and analyzed. The relationship between the flowing state and the structure of the vortex spun yarn is also discussed. The research results can enhance the understanding of the yarn formation principle from viewpoint of the airflow field law inside the nozzle block of Murata vortex spinning.
基金Program for Changjiang Scholars and Innovative Research Team in University,China(No.IRT1220)Shanghai Natural Science Foundation,China(No.13ZR1400900)Keygrant Project of Chinese Ministry of Education(No.113027A)
文摘Based on the mechanical system of free-end fibers and the analysis of pulling free-end fibers out of the spun yarn during spinning,a low-fiber hollow spindle is designed and the air distribution of fluent field is simulated numerically. The negative pressure effect is much bigger at the top of low-fiber hollow spindle than that in Murata No.861,which is more conducive for single fiber to get into the channel of hollow spindle. The tangential velocity in 0-3 mm at the top of hollow spindle increases and the fluctuation of radial velocity is much stronger,which enhance the wrapping effect. In the addition,the distribution of axial velocity remains the same.
基金sponsored by the National Key R&D Program of China(No.2020YFC1910000)the National Natural Science Foundation of China(Grants No 51978153).
文摘Particulate matter(PM)from high-temperature emissions like chemical plants,coal stoves and vehicle exhausts poses a gravel challenge to human health.To address this issue,researchers have explored vari-ous fiber filters,yet the bulk struggle to withstand high temperatures.In this study,mullite fiber sponges were developed utilizing low-cost materials and Kármán vortex solution blow spinning,using surfac-tants to improve the spinnability of the sol.Optimized sponges demonstrate ultralight(19 mg cm^(-3)),temperature-resistant reversible compressibility(50% strain)and a water contact angle of 135°.These sponges exhibited exceptional thermal insulation(thermal conductivity:0.0256 W m^(-1) K^(-1))and per-formed well in high-temperature air filtration.At 800℃,the mullite sponge with a base weight of 35 mg cm^(-2),achieved an average filtration efficiency of 98.18%and 99.57% for PM_(2.5) and PM_(2.5-10),respectively,with a quality value of 0.98 Pa^(-1) at a wind speed of 4 cm s^(-1).This low-cost mullite fiber sponge offers a promising avenue for designing high-performance filtration materials.
