中国农业气象

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冬季日光温室北墙内表面热流分析

王谦;陈景玲;孙治强;赵勇;吴明作;杨喜田;苗蕾;   

  1. 河南农业大学;
  • 出版日期:2010-04-10 发布日期:2010-04-10
  • 基金资助:
    国家科技支撑计划课题“园艺作物安全高效生产关键技术研究与示范”(2006BAD07B04-08)

Heat Flux Analysis of Inner Surface of North Wall in Solar Greenhouse

WANG Qian,CHEN Jing-ling,SUN Zhi-qiang,ZHAO Yong,WU Ming-zuo,YANG Xi-tian,MIAO Lei(Henan Agricultural University,Zhengzhou 450002,China)   

  • Online:2010-04-10 Published:2010-04-10

摘要: 为了摸清日光温室墙体内表面上辐射、对流传热分量和向墙体内部的传导热分量的日变化情况,以及墙体内部传导传热热流状况,以指导温室生产有针对性的采取保温措施,采用墙体内及表面空气多点多日连续温度监测,用传热学中平板表面对流换热和物体内部热传导传热计算方法进行分析,研究日光温室北墙表面热量收支和墙体热量流动状况。结果表明,墙体内40-50cm深度存在日温不变层;40cm热流仅4W.m-2左右。传热学计算表明北墙内表面自然对流为湍流状态,对流传热系数在1.69~4.43W.m-2.K-1。墙体内表面晴天白天最大对流换热量为26.5W.m-2,而墙面接受最大辐射热交换69.8W.m-2;墙内表面向墙内传导传热量最高达83.6W.m-2;随深度增加,热流降低,位相滞后。阴天时热流量迅速减小。结论:在郑州冬季天气条件下,60cm厚墙体已接近合理水平,再增加厚度增强保温效果的潜力不大;北墙表面空气与墙体间传热为湍流状态,而非平流状态;白天北墙表面以辐射换热量为主,是对流换热量的2.6倍。

关键词: 日光温室, 北墙, 对流, 传导, 热流

Abstract: To find out the heat flux of the north wall of the greenhouse,and identify proper thickness of the wall,the temperatures of different depth at top,middle and bottom of the wall,and the air temperatures near inner/outer surface of the wall,were measured. It was showed there were constant temperature layers at the depth of 40-50cm.The heat fluxes at the depth of 40cm were mere 4W·m-2. The calculation result showed that the natural convection of the air near inner surface of the wall was on turbulent flow state,and the convection heat index was 1.69~4.43W·m-2·K-1. The maximum convection heat flux of the inner surface of the wall was 26.5W·m-2 in clear daytime and the wall absorbed radiation 83.6W·m-2 maximally. The conduction heat flux reduced and the phase of the heat flux lagged along with the increase of the depth. The heat flux decreased sharply from clear day to cloudy day. The conclusion was that 60cm was a reasonable thickness of the north wall of the solar greenhouse in zhengzhou,Henan province.

Key words: Solar greenhouse, Solar greenhouse, North wall, Convection, Conduction, Heat flux