Numerical Analysis Of Injection Induced Electrohydrodynamic Plume And Its Application On Heat Transfer Enhancement

Electrohydrodynamics(EHD),as an interdisciplinary subject of electromagnetics and hydrodynamics,plays an important role in the study of classical physical problems and practical applications,including heat and mass transfer enhancement and plasma flow control and so on.The enhancement of heat transfer by electric field has attracted more and more attention in recent years due to its advantages in intelligence,high efficiency,low noise,no mechanical moving parts and simple structure.For complex electro-thermo-convection physics problems,the direct numerical simulation method can obtain comprehensive physical field information and provide more intuitive results,which is of great benefit to the understanding of complex problems themselves.The EHD problems involve the strong non-linear coupling of multiphysical fields.The development of numerical simulation is relatively slow and there is a lack of research on the mechanism and flow details of the EHD problem.The main purpose of this paper is to use the numerical simulation platform based on the finite volume method to study the physical problems of electric and thermal convection in the blade-plate model,and to evaluate the enhancement effect of electric field on heat transfer.Firstly,the mathematical and physical model of electrothermal convection and the theoretical basis of charge injection and discharge process are introduced in detail.Then,the numerical solution method based on finite volume method is introduced,and the calculation modules of flow field,electrostatic field and temperature field are fully validated.Pure electro-convection caused by charge injection is the basis of more complex electro-thermo-convection research.Therefore,the understanding of the structure and characteristics of plume flow is of vital importance.By changing the main dimensionless control parameters in the pure electro-convection model,the flow structure and strength under the influence of these parameters are numerically studied.It is found that the change of electric Reynolds number will cause the change of flow pattern and intensity,while other dimensionless control parameters have different effects on the convection.Electro-thermo-convection involves the interaction of Coulomb force and buoyancy force,including the non-linear coupling of electric field,charge density distribution,thermal field and flow field.Studing the flow structure of electro-thermo convection,and evaluating its heat transfer enhancement effect,have important theoretical value for its application on heat transfer enhancement.Based on the numerical algorithm of electro-thermo-convection,by changing the main dimensionless control parameters in the blade-plate electro-thermo-convection model,the influence ofthe main driving parameters and other parameters on the electro-thermo-convection flow is analyzed.Meanwhile,by calculating the average Nusselt number,the influence of the parameters on the convective heat transfer efficiency is evaluated.This study enriches the theory of electro-hydrodynamics under charge injection mechanism,and conducts a systematic numerical study of the electrothermal convection problem.It is conducive to the in-depth understanding of the interaction between electric field,flow field and temperature field,and also provides a theoretical basis for the practical application of electric field to enhance heat transfer.