【摘要】 穿流式搅拌桨桨叶上的开孔所引起的射流对于提高搅拌效率、降低搅拌能耗起着重要的作用。采用模拟实验方法,研究了全混状态下喷孔出口流速、孔径和孔长对水射流半扩展角β和源点xp/D的影响。研究结果表明:喷孔孔径、孔长以及喷孔前流体的湍动程度对射流发展有很大影响,存在一临界喷孔长径比(H/D)0,1.31 (H/D)0 1.67。当H/D≤(H/D)0时,β随速度(或Re)增加而增大,xp/D随Re增加变化很小;当(H/D)>(H/D)0时,β随速度(或Re)增加而减小,xp/D随Re增加而减小。为了获得较好的混合效果,搅拌桨桨叶上的开孔所引起的射流应有尽量大的扩展效果,因此桨叶上开孔的长径比应小于(H/D)0。更多还原

【Abstract】 A stirrer with jet function has the advantages of higher efficiency and lower energy consumption in mixing. Jet caused by the holes in the blades of the stirrer has strong effects on the mixing performance of the stirrer. It was studied that the effects of the diameters and lengths of orifices on the half spread angle β and virtual origin x_p/D of water jet in mixing conditions by simulating the jet caused by the stirrer. The results showed experimentally that the orifice diameter, length, turbulent degree before orifice have great effect on the spread of jet. The jet half spread angle β has complex reliance on the jet outlet velocity, length diameter ratio and Reynold number. Critical orifice length diameter ratio （H/D）₀ is being and between 1.31 and 1.67 , when （H/D）≤（H/D）₀, β increases with velocity （or Re） to a certain degree, x_p/D changes a little when Re increases; when （H/D）>（H/D）₀, β decreases with velocity （or Re） to a certain degree, x_p/D decreases when Re increases. The H/D of the holes in the blades should be lower than （H/D）₀ to get greater jet half spread angle and better mixing.更多还原