管内组合转子的转动特性是研究其强化传热及防垢阻垢特性的重要基础。为此,本文搭建转速测定实验台,采用光电式转速测定装置对螺旋两叶片转子、大导程螺旋两叶片转子、小外径螺旋两叶片转子及螺旋三叶片转子在管内不同流量条件下以及不同轴向位置处的转速进行了测量,分析了转子的转动特性。测量结果表明:转子转速是由转子在管内所处轴向位置、管内流量、转子的导程、转子的外径以及转子的叶片数等因素共同决定的;转子转速均随管内流量的增加而增加,而且近似地呈线性变化;转子转速均沿管轴向的深入而递减;转子导程越大,转子转速越低;转子外径越小,转子转速越低;转子叶片数的增多只能在管前端很小的范围内使转速增大。最后,获得了4种转子在管内不同流量条件下以及不同轴向位置处的转速拟合关联式。
Rotational characteristics of assembled rotors in tube are the foundation to study its heat transfer enhancement and fouling-preventing performance.Thus,in this paper,the experiment apparatus was built,and rotational speeds of helical two-blade rotor,large-lead helical two-blade rotor,small-diameter helical two-blade rotor and helical three-blade rotor in different flow rates and different axial positions were measured using photoelectric tachometer to analyze the rotational characteristics of assembled rotors.The results showed that rotational speeds of rotors is determined by the factors of axial position of rotor in tube,flow rate in tube,lead of rotor,diameter of rotor,and blade number of rotor.Rotational speeds of the four types of rotors all increased with the increase of flow rate in tube and varied approximately linearly.Rotational speeds of the four types of rotors all decreased with the increase of axial position of rotor in tube.The larger the lead of rotor is,the lower the rotational speed is.The smaller the diameter of rotor is,the lower the rotational speed is.Rotational speeds of rotors can only be improved at a small range in the front of tube by increasing the blade number of rotors.Lastly,the fitting correlations of rotational speeds of the four types of rotors in different flow rates and different axial positions were acquired.