Numerical Simulation And Experimental Research On Convective Heat Transfer In Circular Tube By Coupling Effect Of Electro-hydro-dynamics And Pulsating Flow

Electro-hydro-dynamics, called EHD, is a technology that introducefundamentally electric theories into heat transfer domain for heat transferenhancement accomplished by the coordination among flow field,temperature field and electric field.Pulsating Flow is one kind of fluid type propelled by a flow withconstant pressure gradient (or velocity gradient) and simultaneouslysuperimposed by a sine or cosine pressure gradient (or velocity gradient).It is a novel concept that synthesizing the EHD and Pulsating Flowfor heat transfer enhancement, and if the synthesis generated positivecoupling effect, it would explore a new domain for heat transferenhancement, which should have important economic and social value forsaving energy and easing energy crisis. Therefore, this dissertation haspresented a research on the coupling effect of EHD and Pulsating Flowfor Laminar convective heat transfer enhancement in circular tube withnumerical simulation and experimental research.It can be found in numerical simulation that under the compoundeffect of EHD and Pulsating Flow that the shape of velocity distributionis corrugate and velocity distribution could obviously divided into thelow-fluid-velocity area and high-fluid-velocity area which alternately andcircularly appeared. As the growth of pulsating amplitude, both theterritory of low-fluid-velocity area and the velocity gradient in the areawould increase, meanwhile, the territory of high-fluid-velocity area willshrink toward the center of tube. Furthermore, the low-fluid-velocity areanear the wall will generate a low-fluid-velocity turbulent area where thefluid orientation is disorder.Both the experimental datum and the results of the numerical simulation show that the compound effect of EHD and Pulsating Flow isable to enhancing the laminar convective heat transfer further than soleEHD effect. On the base of this paper, it can be analyzed that thecompound effect of electric mass force and pulsating flow will intensifythe inhomogeneity of electric field distribution in flow, leading to a morevigorous electric convection, and finally enhancing the heat transfer, sothe compound effect of EHD and Pulsating Flow will generate compoundenhancement performance.