高雷诺数下减阻聚合物材料的选型试验研究

Experimental Study on Selection of Drag Reduction Polymer Materials at High Reynolds Number

文章采用水箱中转盘和转筒测扭矩相结合的方法,开展高雷诺数(最高达2.2×10^(7))下减阻聚合物材料的选型试验研究。以目前在减阻方面较为广泛使用的高分子聚合物——聚氧化乙烯(PEO)、聚丙烯酰胺(PAM)、瓜胶等为试验对象,并以PEO为主,研究浓度、数均分子量、混合其他聚合物、剪切、海水等对其减阻效果的影响。获得以下主要结论:(1)减阻率总体上随浓度的增加而增加,就数均分子量为1×10^(7)的PEO而言,低雷诺数(Re<1×10^(7))下,5 mg/L的浓度已饱和,最大减阻率约为60%;(2)减阻率总体上随数均分子量的增加而增加,Re<1.3×10^(7)时,数均分子量大于8×10~6后,减阻率已基本不变;(3)抗剪切性能随浓度、数均分子量的增加而增加,但浓度大于5 mg/L、数均分子量大于8×10~6后,增幅降低;(4)增加浓度,或者混合PAM,均可提升减阻率和抗剪切性能,前者效果更好;(5)海水中与淡水中减阻率相当,但海水中抗剪切能力稍差。

The type selection experiment of drag reduction polymer materials at high Reynolds number(up to 2.2×10^(7))is carried out by using the method of measuring torque on the rotating disc and rotating cylinder in water tank.Taking poly(ethylene oxide)(PEO),polyacrylamide(PAM)and guar gum,which are widely used in drag reduction at present,as experimental objects,the effects of concentration,relative molecular mass,mixing with other polymers,shearing and seawater on drag reduction were studied.The main conclusions are as follows:(1)the drag reduction rate generally increases with the increase of concentration.As far as PEO(M=1×10^(7))is concerned,the concentration of 5 mg/L is saturated at low Reynolds number(Re<1×10^(7)),and the maximum drag reduction rate is about 60%.(2)The drag reduction rate generally increases with the increase of relative molecular mass.When Re<1.3×10^(7),the drag reduction rate is basically unchanged when the relative molecular mass is greater than 8×10~6.(3)The ability to resist shearing increases with the increases of concentration and relative molecular mass,but the increase decreases when the concentration>5 mg/L and relative molecular mass>8×10~6.(4)Increasing the concentration or mixing PAM can improve the drag reduction rate and the ability to resist shearing,and the former has better effect.(5)The drag reduction rate in seawater is equivalent to that in fresh water,but the ability to resist shearing in seawater is slightly poor.