高速离心泵磁性液体新型旋转密封结构的设计及实验研究

Theoretical and Experimental Research on New Type Ferrofluid Rotary Sealing for High Speed Centrifugal Pump

针对垃圾焚烧工程急冷系统中高速离心泵密封问题,设计一种五极六靴二十四齿的磁性液体旋转密封装置,该装置适用于焚烧的高温烟气环境条件,使用寿命长。理论上推导考虑温度和离心力因素的磁性液体密封耐压公式,得出密封耐压力为线速度的二次函数,温度的一次函数。用Ansys有限元分析软件计算该密封结构分别在间隙0.4、0.5、0.6和0.7 mm下的磁性液体磁场分布。结果表明:密封耐压能力随着密封间隙的减小而逐渐递增,而由于漏磁的存在,递增的程度并非线性的;磁力线分布表明,在第一、六极靴和二、五极靴处漏磁较大。密封实验中得出最大间隙为0.7 mm时单级密封耐压能力达到51.7 kPa。

A five-pole,six-shoe and twenty-four-tooth ferrofluid rotary sealing device was designed for the sealing problem of the high-speed centrifugal pump in the rapid cooling system of the waste incineration project.This device is suitable for incineration high-temperature flue gas environmental conditions and has a long service life.The pressure resistance formula with considering the temperature field and centrifugal force was theoretically deduced.It is concluded that the pressure resistance is the quadratic function of the linear velocity,and the linear function of the temperature.The Ansys was used to calculate the magnetic field distribution of the structure under the gaps of 0.4,0.5,0.6 and 0.7 mm.It is found that the pressure resistance of the sealing structure gradually increases with the decrease of the sealing gap,and due to the existence of magnetic leakage,the degree of increase of the pressure resistance is not linear.The distribution of magnetic field lines shows that the magnetic leakage is a little larger at the first and sixth pole shoes,the second and fifth pole shoes.In the sealing experiment,it is concluded that when the maximum gap is 0.7 mm,the single-stage sealing pressure capacity reaches at 51.7 kPa.