化工进展
化工進展
화공진전
CHEMICAL INDUSTRY AND ENGINEERING PROGRESS
2015年
5期
1259-1263
,共5页
张琳%崔腾飞%蒋枫%单高峰%黄子雄%胡泽训%赵利群
張琳%崔騰飛%蔣楓%單高峰%黃子雄%鬍澤訓%趙利群
장림%최등비%장풍%단고봉%황자웅%호택훈%조리군
透明导电膜%升膜蒸发%流型%传热系数
透明導電膜%升膜蒸髮%流型%傳熱繫數
투명도전막%승막증발%류형%전열계수
the transparent conductive film%climbing film evaporation%flow pattern%heat transfer coefficient
为了探究热流密度、真空度和流量对升膜蒸发器传热性能的影响,以及对升膜加热管内流体流型进行观测和分析,本文建立了升膜蒸发系统传热实验平台,对升膜蒸发器的传热特性和流体流型进行实验研究。实验所用升膜管管长2200mm,升膜管采用镀透明导电膜石英管,工作介质为水;升膜管蒸发侧采用电加热方式;研究了热流密度(6.71kW/m2≤q≤26.79kW/m2)、流量(20L/h≤M≤100L/h)和真空度(0≤P≤15kPa)对升膜加热管流体流型和传热特性的影响。结果表明:通过电加热的方式可以实现石英管内溶液的升膜蒸发,并能观测到泡状流、块状流、弹状流、柱塞流、环状流和雾状流;热流密度低于6.71kW/m2时无法形成升膜蒸发,随着蒸发侧热流密度的增大,升膜管内环状流长度增大,管内传热系数增大;随着流量的增大,升膜管内液体湍流强度增大,管内传热系数增大;真空度对流体流型影响较大。
為瞭探究熱流密度、真空度和流量對升膜蒸髮器傳熱性能的影響,以及對升膜加熱管內流體流型進行觀測和分析,本文建立瞭升膜蒸髮繫統傳熱實驗平檯,對升膜蒸髮器的傳熱特性和流體流型進行實驗研究。實驗所用升膜管管長2200mm,升膜管採用鍍透明導電膜石英管,工作介質為水;升膜管蒸髮側採用電加熱方式;研究瞭熱流密度(6.71kW/m2≤q≤26.79kW/m2)、流量(20L/h≤M≤100L/h)和真空度(0≤P≤15kPa)對升膜加熱管流體流型和傳熱特性的影響。結果錶明:通過電加熱的方式可以實現石英管內溶液的升膜蒸髮,併能觀測到泡狀流、塊狀流、彈狀流、柱塞流、環狀流和霧狀流;熱流密度低于6.71kW/m2時無法形成升膜蒸髮,隨著蒸髮側熱流密度的增大,升膜管內環狀流長度增大,管內傳熱繫數增大;隨著流量的增大,升膜管內液體湍流彊度增大,管內傳熱繫數增大;真空度對流體流型影響較大。
위료탐구열류밀도、진공도화류량대승막증발기전열성능적영향,이급대승막가열관내류체류형진행관측화분석,본문건립료승막증발계통전열실험평태,대승막증발기적전열특성화류체류형진행실험연구。실험소용승막관관장2200mm,승막관채용도투명도전막석영관,공작개질위수;승막관증발측채용전가열방식;연구료열류밀도(6.71kW/m2≤q≤26.79kW/m2)、류량(20L/h≤M≤100L/h)화진공도(0≤P≤15kPa)대승막가열관류체류형화전열특성적영향。결과표명:통과전가열적방식가이실현석영관내용액적승막증발,병능관측도포상류、괴상류、탄상류、주새류、배상류화무상류;열류밀도저우6.71kW/m2시무법형성승막증발,수착증발측열류밀도적증대,승막관내배상류장도증대,관내전열계수증대;수착류량적증대,승막관내액체단류강도증대,관내전열계수증대;진공도대류체류형영향교대。
In order to explore the effects of the heat flux density,vacuum degree and flow on heat transfer performance of climbing film evaporator,this paper observed and analyzed the fluid flow pattern in the climbing film heating pipe,established the heat transfer experimental platform of climbing film evaporation system,and studied the heat transfer characteristics and fluid flow pattern of climbing film evaporator. The length of the climbing film evaporation pipe used in the experiment was 2200mm,the climbing film pipe was a quartz tube coated with transparent conductive film,the working medium was water,and electrical heating was employed in the evaporation section. The effects of the heat flux densities(6.71kW/m2≤q≤26.79kW/m2),flow rates(20L/h≤M≤100L/h) and vacuum degrees(0≤P≤15kPa) on fluid flow pattern and heat transfer characteristics of the climbing film heating pipe were studied. The results showed that climbing film evaporation for the solution in the quartz pipe could be achieved in the way of electric heating. And bubbly flow,bulk flow,slug flow,plug flow,annular flow and mist flow were observed. When heat flux was less than 6.71kW/m2,climbing film evaporation was not formed. With the increase of the evaporation side heat flux density,annular flow length increased in the climbing film pipe,and the inner pipe heat transfer coefficient increased. With the increases of the flow,liquid turbulence intensity increased inside the climbing film pipe,the inner pipe heat transfer coefficient increased as well. And vacuum degree had a significant influence on the fluid flow pattern.