Optimization Performance Study Of The Couping Heat Transfer Enhancement Heat Exchanger With Ehd And Pulsating Flow

Based on the technology of enhanced heat transfer of electric field and pulsatingflow, the concept of pulsating and electric field compound enhance heat transfer wasproposed by the dissertation. It is a novel concept that synthesizing the EHD andPulsating Flow for heat transfer enhancement, and if the synthesis generate positivecoupling effect, it would explore a new domain for heat transfer enhancement, whichshould have important economic and social value for saving energy and easing energycrisis.The numerical method and experimental method were used to study the couplingeffect of pulasating and electric field for convective heat transfer enhancement in circulartube, which contained the flow field, velocity field, heat transfer, flow resistance andcomprehensive performance under different parameters.The result of numerical simulation shows that the velocity distribution in tubeappears massive turbulent area and wave oscillation phenomenon when the electric fieldand the pulsating flow take effect simultaneously. The pulsating flow and electric fieldcan produce a compound enhancement effect on flow field.Both the results of numerical simulation and experiment show that the enhancedheat transfer coefficient has no obvious enhancement under the action of pulsating flowseparately, but it has a growth with the voltage increases under the action of electric fieldseparately. The enhanced heat transfer coefficient increases with frequency and voltageincrease, and decreases with flow increases when the electric field and the pulsating flowtake effect simultaneously. The technology of enhanced heat transfer of the electric fieldand the pulsating flow reaches the maximum enhanced heat transfer coefficient under thecondition of low flow, high frequency and high voltage, the value is1.24. The pulsatingflow and electric field can influence each other, and can achieve a compoundenhancement effect in terms of heat transfer. Both the results of experiment and numerical simulation show that the enhanceddrag coefficient has a certain level of growth under the action of pulsating flowseparately, but it has no obvious enhancement under the action of electric field. Theenhanced drag coefficient increases with frequency and flow increase, and remainsunchanged with the increase of the voltage value when the electric field and the pulsatingflow take effect simultaneously. The technology of enhanced heat transfer of the electricfield and the pulsating flow reaches the maximum enhanced drag coefficient under thecondition of large flow and high frequency, the value is1.91.The result of experiment shows that the evaluation factor reaches maximum underthe condition of low flow and low frequency when the pulsating flow take effectseparately, the value is1.05. And the evaluation factor reaches maximum under thecondition of low flow and high voltage when the pulsating flow take effect separately, thevalue is1.18. When the electric field and the pulsating flow take effect simultaneously,the evaluation factor increases with with the frequency increase, and decreases with theflow increase, and remains unchanged with the increase of the voltage value. Thetechnology of enhanced heat transfer of the electric field and the pulsating flow reachesthe maximum overall performance under the condition of low flow, low frequency andhigh voltage, the value is1.24.The technology of enhanced heat transfer of the electric field and the pulsatingflow reaches the maximum enhanced heat transfer coefficient under the condition of lowflow, high frequency and high voltage, and reaches the maximum enhanced dragcoefficient under the condition of large flow and high frequency, and reaches themaximum overall performance under the condition of low flow, low frequency and highvoltage.