化工学报
化工學報
화공학보
CIESC Jorunal
2015年
10期
3841-3848
,共8页
屈晓航%田茂诚%张冠敏%冷学礼
屈曉航%田茂誠%張冠敏%冷學禮
굴효항%전무성%장관민%랭학례
直接接触冷凝%不凝气体%汽羽长度%传热系数
直接接觸冷凝%不凝氣體%汽羽長度%傳熱繫數
직접접촉냉응%불응기체%기우장도%전열계수
direct contact condensing%non-condensable gas%jet plume length%heat transfer coefficient
对含不凝气体蒸汽射流在冷水中直接接触冷凝现象进行了实验研究,通过测量流场中的温度分布确定汽羽长度,进而推导其传热系数。实验使用直径为1.6 mm的圆形喷嘴,出口混合气体质量流量密度在100~330 kg·m?2·s?1之间,不凝气体的含量在0~15%之间,冷水温度在300~340 K之间。实验结果表明:不凝气体的加入,使喷嘴出口附近的温度下降减慢;汽羽长度随不凝气体含量的增加而变长,其受喷嘴出口质流密度和过冷度的影响规律与纯蒸汽射流一致;冷凝传热系数在0.7~2 MW·m?2·K?1之间,随过冷度的增大和不凝气体含量的增加而减小,受气体流量的影响较小。对实验数据进行拟合,获得了汽羽长度的关联式,并由此得到了冷凝传热系数关联式。
對含不凝氣體蒸汽射流在冷水中直接接觸冷凝現象進行瞭實驗研究,通過測量流場中的溫度分佈確定汽羽長度,進而推導其傳熱繫數。實驗使用直徑為1.6 mm的圓形噴嘴,齣口混閤氣體質量流量密度在100~330 kg·m?2·s?1之間,不凝氣體的含量在0~15%之間,冷水溫度在300~340 K之間。實驗結果錶明:不凝氣體的加入,使噴嘴齣口附近的溫度下降減慢;汽羽長度隨不凝氣體含量的增加而變長,其受噴嘴齣口質流密度和過冷度的影響規律與純蒸汽射流一緻;冷凝傳熱繫數在0.7~2 MW·m?2·K?1之間,隨過冷度的增大和不凝氣體含量的增加而減小,受氣體流量的影響較小。對實驗數據進行擬閤,穫得瞭汽羽長度的關聯式,併由此得到瞭冷凝傳熱繫數關聯式。
대함불응기체증기사류재랭수중직접접촉냉응현상진행료실험연구,통과측량류장중적온도분포학정기우장도,진이추도기전열계수。실험사용직경위1.6 mm적원형분취,출구혼합기체질량류량밀도재100~330 kg·m?2·s?1지간,불응기체적함량재0~15%지간,랭수온도재300~340 K지간。실험결과표명:불응기체적가입,사분취출구부근적온도하강감만;기우장도수불응기체함량적증가이변장,기수분취출구질류밀도화과랭도적영향규률여순증기사류일치;냉응전열계수재0.7~2 MW·m?2·K?1지간,수과랭도적증대화불응기체함량적증가이감소,수기체류량적영향교소。대실험수거진행의합,획득료기우장도적관련식,병유차득도료냉응전열계수관련식。
Direct contact condensation characteristics in cool water of steam jet with non-condensable gas in it were investigated experimentally in this paper. The jet plume length of the mixture gas was obtained by measuring temperature field, which was used later to get condensation heat transfer coefficient. Using a circular nozzle with a diameter of 1.6 mm, this experiment covered the range of mixture gas mass flux from 100 to 330 kg·m?2·s?1, non-condensable gas content from 0 to 15% and cool water temperature from 300 to 340 K. The results showed that the existence of non-condensable gas led the decrease of temperature more slowly near the nozzle exit and the increase of jet plume length with increasing content of non-condensable gas. The effect of the addition of non-condensable gas on mixture mass flux and water subcooling was the same as pure steam jet. The condensation heat transfer coefficient was found to be in the range of 0.7 and 2 MW·m?2·K?1, and it decreased with increasing subcooling and non-condensable gas content, while the mixture mass flux has a little effect on it. Finally, correlations predicting the jet plume length and the condensation heat transfer coefficient were obtained by fitting the experimental dates.