不同温度下磁场对外涡型ECP中亚微米颗粒分离的影响

Influences of Magnetic Field on the Separation of Submicron Particles in Outer Vortex ECP at Different Temperatures

针对旋风除尘器中亚微米颗粒捕集效率低下的问题,探究了利用洛伦兹力和电场力联合作用来提高亚微米颗粒分离效率的可能性.将4根电极添加在旋风除尘器中组成外涡型静电旋风除尘器(electrostatic cyclone precipitator,ECP),并在其中引入磁场,构建了磁场作用下外涡型静电旋风除尘器简化模型;在建立流场、颗粒动力场、电磁场和温度场4场相互耦合作用理论模型的基础上,对不同温度下亚微米颗粒在外涡型静电旋风除尘器的除尘效率进行数值模拟.数值结果表明,磁场的引入显著提高了静电旋风除尘器对亚微米颗粒的分离性能,有效降低了温度对除尘效率的削弱率;随着温度的降低或磁感应强度的增大,温度对亚微米颗粒综合效率的削弱率逐渐减小,但磁场的贡献率逐渐增大,且逐渐趋于平缓;温度越低、磁感应强度越大更有利于亚微米颗粒的分离,但磁感应强度越小和温度越高时,磁场作用越显著.相关研究结果对传统静电旋风除尘器外加磁场设备改造和除尘相关工业领域的技术革新有一定参考.

Aiming at the problem of lowtrapping efficiency for submicron particles in cyclone,the possibility of combination effects of the Lorentz force and the electric field force to improve the submicron particles separation efficiency was explored.Four corona wires were added into the cyclone to form the outer vortex electrostatic cyclone precipitator(ECP),in which magnetic field was introduced,and the simplified model of outer vortex ECP under magnetic field effect was developed.On the basis of establishing the theoretical model with four-field coupling interaction between fluid field,particle dynamic field,electromagnetic field and temperature field,the removal efficiency of submicron particles in outer vortex ECP at different temperatures was simulated.The numerical results indicate that the introduction of magnetic field significantly improves the separation performance of ECP for submicron particles,and effectively reduces the weakening rate of temperature on removal efficiency.With the decreasing temperature or the increasing magnetic flux density,the weakening rate of temperature to the overall efficiency of submicron particles gradually decreases,but the contribution rate of magnetic field gradually increases and tends to be gentle.The lower temperature or the greater magnetic flux density is better for the separation of submicron particles.However,the smaller the magnetic flux density and the higher the temperature,the more significant the magnetic field effect.The research results can provide a reference for the traditional equipment modification of ECP by applying magnetic field and the technological innovation of dust removal related industrial fields.