化工进展
化工進展
화공진전
CHEMICAL INDUSTRY AND ENGINEERING PROGRESS
2015年
6期
1557-1563,1581
,共8页
微管%振动%强化传热%微尺度%传热%对流
微管%振動%彊化傳熱%微呎度%傳熱%對流
미관%진동%강화전열%미척도%전열%대류
microtube%vibration%enhanced heat transfer%microscale%heat transfer%convection
目前针对微细管管外同时有自然对流和周期横向振动存在情况下的混合对流问题鲜有研究。为了探究这种现象，进而开发一种新型的换热器，本文提出了一种由4根冷热微细管组成的微管阵列，将其平行放置于有中间流体的圆形腔体内，并对管束施加微小横向振动的混合对流传热机理进行研究。详细描述了实验系统及实验方法，以及后期对实验数据的处理方法，得到了传热Nu数随管间自然对流强度Ra数，强迫振动Rev数等量纲为1参数的变化曲线；揭示了该结构形式下传热特性随冷热管温差、振动频率、微管振幅等传热规律。结果表明，横向振动在小温差情况下传热强化效果更为明显。将本文实验数据与Lemlich单管振动实验中的数据进行对比，表明了振动对4根微管阵列的强化传热效果比单根管更明显。
目前針對微細管管外同時有自然對流和週期橫嚮振動存在情況下的混閤對流問題鮮有研究。為瞭探究這種現象，進而開髮一種新型的換熱器，本文提齣瞭一種由4根冷熱微細管組成的微管陣列，將其平行放置于有中間流體的圓形腔體內，併對管束施加微小橫嚮振動的混閤對流傳熱機理進行研究。詳細描述瞭實驗繫統及實驗方法，以及後期對實驗數據的處理方法，得到瞭傳熱Nu數隨管間自然對流彊度Ra數，彊迫振動Rev數等量綱為1參數的變化麯線；揭示瞭該結構形式下傳熱特性隨冷熱管溫差、振動頻率、微管振幅等傳熱規律。結果錶明，橫嚮振動在小溫差情況下傳熱彊化效果更為明顯。將本文實驗數據與Lemlich單管振動實驗中的數據進行對比，錶明瞭振動對4根微管陣列的彊化傳熱效果比單根管更明顯。
목전침대미세관관외동시유자연대류화주기횡향진동존재정황하적혼합대류문제선유연구。위료탐구저충현상，진이개발일충신형적환열기，본문제출료일충유4근랭열미세관조성적미관진렬，장기평행방치우유중간류체적원형강체내，병대관속시가미소횡향진동적혼합대류전열궤리진행연구。상세묘술료실험계통급실험방법，이급후기대실험수거적처리방법，득도료전열Nu수수관간자연대류강도Ra수，강박진동Rev수등량강위1삼수적변화곡선；게시료해결구형식하전열특성수랭열관온차、진동빈솔、미관진폭등전열규률。결과표명，횡향진동재소온차정황하전열강화효과경위명현。장본문실험수거여Lemlich단관진동실험중적수거진행대비，표명료진동대4근미관진렬적강화전열효과비단근관경명현。
Little research has been done on mixed convection in the existence of natural convection and periodic vibration transversely around microtubes. In order to investigate this situation and develop a new-type heat exchanger,this research established horizontally parallelized hot and cold microtube array immersed in an adiabatic cylindrical enclosure,and investigated the heat transfer mechanism of mixed convection with transverse micro-vibration full of third fluid. The natural convection surrounding the hot and cold microtubes in the cylindrical enclosure was measured at various inlet temperatures and mass flowrates. In addition,experiment system,methods and data-processing were described in detail. The relationship of Nusselt number with Ra number and Rev number was obtained. These parameters disclosed the heat transfer law of heat-transfer characteristics at temperature differences between hot and cold tubes,vibration frequencies and microtube amplitudes. The results showed that the enhanced heat transfer was more remarkable at small temperature differences under vibrating conditions. The comparison between experimental data and Lemlich’s single tube vibration data showed heat transfer due to vibration with four microtubes was more distinct.
