Numerical Simulation And Experimental Research On Heat Transfer And Resistance Characteristics Of Heat Transfer Elements

Rotary air preheaters are extensively used in power plants for theirhigh heat transfer efficiency, compact structure, good corrosion resistance,low operation costs, and so on. Heat transfer elements are the keycomponent of rotary air preheaters and their heat transfer and resistancecharacteristics largely affect the economy and safety of rotary airpreheaters. So, it is of great significance to research on heat transfer andresistance characteristics of different elements styles for better design andselection.Numerical simulation and thermal state experiment methods are usedto study the effects of different geometric structures on heat transfer andresistance characteristics of heat transfer elements.By2D numerical simulations on single-corrugation channel, it isfound that the corrugation structures strengthen air disturbance andimprove the turbulence intensity inside the channel. Compared with anflat-plate channel flow simulation, the result shows that the presence ofcorrugation structures largely shorten the length required for fully developed turbulence flow. In addition, because of the enhancement ofthe turbulence flow, temperature boundary layer thickness insingle-corrugation channel is obviously thinner than that in flat-platechannel, which do a good favor to convective heat transfer. The height ofthe corrugation has a significant influence on the thickness of thetemperature boundary layer.By numerical simulations on models of different angle betweenlocating plate and corrugated plate, the simulation results show the wholeconvection heat transfer coefficient and pressure drop are both increasedwith the angle getting bigger. The rising trend are getting quick when theangle is bigger than60°. As the angle getting bigger, the increase rate ofpressure drop is larger than that of convection heat transfer coefficient. Inorder to get the best economy, both the two aspects need to be consideredto obtain the best angle.By numerical simulations on3heat transfer elements of differentlocating plate, it is found that the element which consists of locating platewith corrugations and corrugated plate shows the best heat transferperformance, consists of flat locating plate and corrugated plate show theworst heat transfer performance. A thermal experiment proves thenumerical simulation conclusions.