高强度PA单丝拖网水槽试验研究

强度相同条件下,聚酰胺(PA)单丝网衣的水阻力比聚乙烯(PE)捻线网衣的要小,所以在普通PE网衣拖网中,可以对部分网衣结构设计替换高强度PA单丝网衣,以降低拖网阻力,达到节能降耗的目的。以虾拖网为实物拖网,按照田内模型试验准则,设计改进型PA网衣的模型拖网,通过水槽模型试验,对比研究改进型PA网衣和传统PE网衣的拖网渔具性能和节能效果。试验结果显示,在相同拖速条件下,水平扩张比(L/S)为0.40、0.50、0.60时,改进型模型拖网比对照模型拖网所受阻力分别可降低12.14%、8.11%、6.00%,网口高度分别可提高20.00%、22.09%、25.64%,网口扩张系数分别可提高28.57%、27.27%、30.00%,能耗系数分别可减少30.61%、29.32%、29.18%。研究表明,高强度PA单丝网衣拖网能起到降低渔具阻力、提高拖网性能的作用,可在渔业生产中推广应用。

Flume experimental research on high-strength PA monofilament trawl

With the same strength grades,polyamide ( PA) monofilament netting suffers less resistance than polyethylene (PE) twist wire netting in water,so some parts of PE twist wire trawl can be replaced by PA monofilament material in order to reduce resistance and save energy.In this paper,a shrimp trawl was selected, based on which a PE twist wire model trawl and a structure-modified PA monofilament model trawl were designed following Tauti model experiment standard and their performance and energy saving property were researched and compared by flume experiment. The experiment results showed that under same testing conditions,the properties of modified PA monofilament model trawl were better than PE twist wire model trawl.At the same speed,when the L/S ratios of the two model trawls were 0.40,0.50 and 0.60,compared with the PE twist wire model trawl,the resistance of modified PA monofilament model trawl decreased by 12.14%,8.11%,and 6.00%, net opening height raised by 20. 00%, 22. 09% and 25. 64%, vertical expand coefficient increased by 2857%,27.27% and 30%,and the energy consumption coefficient decreased by 18.34%,24.81% and 26.23%, respectively.The research shows that high-strength PA monofilament trawl could reduce resistance suffered by fishing gears and improve their performances,and can be extended and applied in fishery practices.