本文選題：非對稱布置　切入點：縱向渦發(fā)生器　出處：《河北工業(yè)大學(xué)》2014年碩士論文

【摘要】：縱向渦發(fā)生器是一種有效的被動式強化傳熱方式。為進一步提高縱向渦發(fā)生器的強化傳熱效果,本文采用數(shù)值模擬的方法研究了縱向渦發(fā)生器的布置方式對矩形通道和圓形通道內(nèi)的流動與換熱的影響規(guī)律,得到的主要結(jié)論如下:對于矩形通道,Re的取值范圍為500~2000,分析矩形翼縱向渦發(fā)生器對稱與非對稱布置時的流動與換熱特性,結(jié)果表明:非對稱布置縱向渦發(fā)生器比對稱布置縱向渦發(fā)生器的Nu數(shù)減少4%~6%,但阻力因子f減少11%~22%。非對稱布置縱向渦發(fā)生器的綜合換熱性能η比對稱布置方式增加了5%~20%,表明非對稱布置縱向渦發(fā)生器的綜合換熱性能更好。同時,對不同尺寸矩形翼對對稱布置模型的翼間距、翼高、翼長、攻角等進行優(yōu)化設(shè)計。對于圓管翅片換熱器,Re的取值范圍為500~2500,分析矩形翼縱向渦發(fā)生器對稱與非對稱布置時的流動與換熱特性,結(jié)果發(fā)現(xiàn):縱向渦發(fā)生器對圓管后側(cè)的換熱起到了增強作用,使圓管后側(cè)的尾跡區(qū)明顯減少,改善了換熱最差的區(qū)域的換熱。非對稱布置縱向渦發(fā)生器比對稱布置的Nu數(shù)僅減少2.6%~6.3%,阻力因子f減少了2.8%~18%,綜合換熱性能η提高2.4%~13%。利用大渦模擬方法研究了矩形通道內(nèi)布置相同尺寸矩形翼對對稱布置、不同尺寸矩形翼對對稱布置、單個矩形翼交替等三種布置方式對流動與換熱特性的影響。結(jié)果發(fā)現(xiàn):當流體進入通道后,在縱向渦發(fā)生器的尾部會形成縱向渦旋,這些縱向渦旋在流動方向上不斷的產(chǎn)生、發(fā)展和消亡,并且對加熱面形成沖掃作用。對比渦量圖、斷面溫度分布圖和斷面壓力分布圖得出,縱向渦發(fā)生器誘導(dǎo)的縱向渦使近壁面處的溫度梯度發(fā)生變化,壓力變化明顯的地方主要集中在縱向渦集中的區(qū)域。
[Abstract]:Longitudinal vortex generator is an effective passive heat transfer enhancement method.In order to further improve the heat transfer enhancement effect of longitudinal vortex generator, the effect of the arrangement of longitudinal vortex generator on the flow and heat transfer in rectangular and circular channels is studied by numerical simulation.The main conclusions are as follows: the flow and heat transfer characteristics of rectangular wing longitudinal vortex generator under symmetrical and asymmetric arrangement are analyzed for the rectangular channel with a range of 500 ~ 2000 re.The results show that the number of Nu in the asymmetrical arrangement of longitudinal vortex generators is reduced by 4 and 6, but the resistance factor f is reduced by 11 and 22.The comprehensive heat transfer performance 畏 of asymmetric arrangement longitudinal vortex generator is increased by 5% 20% than that of symmetrical arrangement mode, which indicates that asymmetric arrangement longitudinal vortex generator has better comprehensive heat transfer performance.At the same time, the space, height, length and angle of attack of the symmetrical arrangement model of rectangular wing with different sizes are optimized.For the tube finned heat exchanger, the value range of re is 500 ~ 2500. The flow and heat transfer characteristics of rectangular wing longitudinal vortex generator are analyzed when it is symmetrical and asymmetric. The results show that the longitudinal vortex generator enhances the heat transfer at the back of the tube.The wake area at the back of the tube is reduced obviously, and the heat transfer in the worst heat transfer region is improved.Compared with the symmetrical arrangement, the number of Nu in asymmetrical vertical vortex generator is only reduced by 2.6% and 6.3%, the resistance factor f is reduced by 2.8%, and the integral heat transfer performance 畏 is increased by 2.4% and 13% respectively.The effects of the same size rectangular wing pair symmetrical arrangement, different size rectangular wing pair symmetrical arrangement and single rectangular wing alternate arrangement on the flow and heat transfer characteristics in rectangular channel are studied by using large eddy simulation method.The results show that when the fluid enters the channel, the longitudinal vortex will form in the tail of the longitudinal vortex generator, which will produce, develop and die out in the flow direction, and form a scouring effect on the heating surface.Compared with vorticity diagram, cross-section temperature distribution diagram and cross-section pressure distribution diagram, it is concluded that longitudinal vortex induced by longitudinal vortex generator changes the temperature gradient near the wall, and the pressure change is mainly concentrated in the region of longitudinal vortex concentration.
【學(xué)位授予單位】：河北工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TK124

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