聚乙烯编织线替代普通聚乙烯捻线对拖网性能的影响

聚乙烯编织网线比普通聚乙烯捻线强度高,用编织线来替代目前的普通捻线,可降低拖网渔具的阻力从而达到节能降耗的目的。本文通过实际取样测试,比较了两种网线的拉伸性能,在不降低原拖网渔具的单线结强力的前提下,用聚乙烯编织线代替原普通捻线,并通过模型试验研究其对拖网渔具性能的影响和节能效果。结果表明:单线结强力相同的两种网线,编织线的直径可比普通网线的直径下降15.17%以上。本试验编织线拖网的平均网线直径比原普通捻线拖网下降16.00%,网具阻力面积(线面积)从304.57 m2下降到256.47 m2,下降了15.79%。同等试验条件下,编织线拖网的阻力比普通捻线拖网下降17.25%左右,而网口高度的变化则不明显。能耗系数的计算结果为编织线拖网过滤同体积的水体所消耗的能量比普通捻线拖网下降16.67%。功率消耗的分析表明,消耗同样的功率,440 kW的双拖渔船使用编织线拖网,拖速可比普通捻线拖网提高8.33%,如采用和普通捻线拖网同样的拖速作业,则去掉起、放网所消耗的时间,以一天正常拖网作业18 h计算,可节约燃油77 L左右。

Experimental research on trawl performance of braided polyethylene netting twine replacing common polyethylene twisting

Polyethylene is the most widely used net material in fishing trawls,and the strength of braided polyethylene netting twine is better than common polyethylene twisting.Using braided polyethylene netting twine to replace the current common polyethylene twisting can reduce the resistance of the trawl fishing gear,achieving the purpose of energy saving.This study compared the tensile mechanical properties of the two netting twines,and used braided polyethylene netting twine to replace the current common polyethylene twisting without reducing the knot strength,and trawl fishing gear performance and energy-saving effects were tested in flume tank.The results showed that:with the same knot strength,the diameter of braided polyethylene netting twine decreased by 15.17%.The average diameter of the braided netting twine decreased by 16% compared to common twisting,and twine area decreased by 15.79%,from 304.57 m2 to 256.47m2.Under the same experimental conditions,using braided netting twine,the trawl resistance decreased by 17.25%,while height opening of the trawl didn't change obviously.The calculation of the energy consumption coefficient showed that,filtering the same volume of water,the trawl using braided polyethylene netting twine decreased by 16.67%.Analysis of power consumption showed that,when consuming the same power for 440 kW dual-dragging fishing trawl,using braided polyethylene netting twine,trawling speed increased by 8.33%,thus in the same trawling speed,it could save 77 L fuel in one fishing day.