The design guideline for the air suction drawing system with auxiliary air was analyzed,a spunbonding nonwoven system named PADHL1-3200 was designed and polypropylene(PP) spunbonded nonwoven fabrics with excellent pro...The design guideline for the air suction drawing system with auxiliary air was analyzed,a spunbonding nonwoven system named PADHL1-3200 was designed and polypropylene(PP) spunbonded nonwoven fabrics with excellent properties were achieved after many trial runs.On the other hand,the suction air velocity(VA) was calculated and the influence of VA on the bonding strengh of PP nonwoven fabrics was studied as well.It was found that VA is 1.5-2.5 times of the spinning velocity.With the increase of VA,PP fibers become finer and the bonding strength of PP nonwoven fabrics increases as well.展开更多
Cutter-suction dredger transports slurry through pipeline. But the pipeline is easy to be jammed and frayed because of huge resistance, resulting in limited exertion of dredger and high energy consumption. One of the ...Cutter-suction dredger transports slurry through pipeline. But the pipeline is easy to be jammed and frayed because of huge resistance, resulting in limited exertion of dredger and high energy consumption. One of the solutions is air injection transporting, which can reduce the resistance in pipeline. This paper makes research on the relations between pipeline distance and other factors such as slurry concentration, pressure of air injection and transportation distance, by making use of Prof. Aluf Orell＇ s slug model. The test data prove that the key factors are slurry concentration and air volume fraction, and that high slurry concentration and low air volume fraction can reduce more resistance, and such reducing effect becomes weaker with the increase of transportation distance.展开更多
Due to the maize growing agronomy requires ground covered by mulch film in the arid zones of the China Northwest region,the seed-metering device must roll over,break the film,and then throw seeds into soil.However,the...Due to the maize growing agronomy requires ground covered by mulch film in the arid zones of the China Northwest region,the seed-metering device must roll over,break the film,and then throw seeds into soil.However,the uneven ground can cause the seed-metering device to shake,reducing seed-metering performance.To improve the adaptability for different shapes of maize seeds,a air suction wheel type seed-metering device with elastic pad was developed for better seed extraction and bump resistance.Firstly,the advantages and influencing factors of the elastic pad were analyzed through four processes of metering seeds.Secondly,the velocity distributions of six diameters of the suction hole are compared to determine the range with FLUENT.Then,a one-factor experiment was conducted to analyze the pattern of the factors(the seed layer height,the critical vacuum,the rotational speed of the seed disk,and the suction hole diameter)influencing the metering seed performance.Finally,a five-level quadratic rotation orthogonal design was used to optimize the parameters.Results show that the optimal values are that the seed layer height is 40 mm,and the critical vacuum is 2.85 kPa,and the rotational speed of the seed disk is 20.1 r/min.The validation experiment resulted in a 93.79%qualified index,with a 4.02%missing index and a 2.19%multiple index.展开更多
文摘The design guideline for the air suction drawing system with auxiliary air was analyzed,a spunbonding nonwoven system named PADHL1-3200 was designed and polypropylene(PP) spunbonded nonwoven fabrics with excellent properties were achieved after many trial runs.On the other hand,the suction air velocity(VA) was calculated and the influence of VA on the bonding strengh of PP nonwoven fabrics was studied as well.It was found that VA is 1.5-2.5 times of the spinning velocity.With the increase of VA,PP fibers become finer and the bonding strength of PP nonwoven fabrics increases as well.
文摘Cutter-suction dredger transports slurry through pipeline. But the pipeline is easy to be jammed and frayed because of huge resistance, resulting in limited exertion of dredger and high energy consumption. One of the solutions is air injection transporting, which can reduce the resistance in pipeline. This paper makes research on the relations between pipeline distance and other factors such as slurry concentration, pressure of air injection and transportation distance, by making use of Prof. Aluf Orell＇ s slug model. The test data prove that the key factors are slurry concentration and air volume fraction, and that high slurry concentration and low air volume fraction can reduce more resistance, and such reducing effect becomes weaker with the increase of transportation distance.
基金National Natural Science Foundation of China(Grant No.52065004,52365030)Lanzhou Municipal Young Talent Innovation Project(Grant No.2023-QN-146)+2 种基金Major Cultivation Project of Collegiate Scientific Research and Innovation Platform of Gansu Provincial Department of Education(2024CXPT-15)Special Project of Gansu Provincial Commissioner for Science and Technology(23CXGA0066)Gansu Agricultural Machinery R&D,Manufacturing and Promotion Application in 2023 Integrated Pilot Project(3-3).
文摘Due to the maize growing agronomy requires ground covered by mulch film in the arid zones of the China Northwest region,the seed-metering device must roll over,break the film,and then throw seeds into soil.However,the uneven ground can cause the seed-metering device to shake,reducing seed-metering performance.To improve the adaptability for different shapes of maize seeds,a air suction wheel type seed-metering device with elastic pad was developed for better seed extraction and bump resistance.Firstly,the advantages and influencing factors of the elastic pad were analyzed through four processes of metering seeds.Secondly,the velocity distributions of six diameters of the suction hole are compared to determine the range with FLUENT.Then,a one-factor experiment was conducted to analyze the pattern of the factors(the seed layer height,the critical vacuum,the rotational speed of the seed disk,and the suction hole diameter)influencing the metering seed performance.Finally,a five-level quadratic rotation orthogonal design was used to optimize the parameters.Results show that the optimal values are that the seed layer height is 40 mm,and the critical vacuum is 2.85 kPa,and the rotational speed of the seed disk is 20.1 r/min.The validation experiment resulted in a 93.79%qualified index,with a 4.02%missing index and a 2.19%multiple index.
