【摘要】 本文对倾斜角度φ=0°、15°、30°、45°、60°和90°的夹层内空气自由运动放热过程进行了实验研究。对国外在这方面的研究概况作了简要的评述。在对已有的几种主要经验公式进行分析的基础上,提出了综合实验数据的方法,从而得出了较精确的实用经验公式。这些公式可用于太阳能集热器的设计计算。 本文还结合过程机理的分析讨论了AR比值对夹层放热的影响。更多还原

【Abstract】 This paper presents the results of an experimental investigation of natural convection in air layer at various aspect ratios and angles. The Rayleigh number range covered is-from subcritical to 106; the range of the angles of inclination, measured from the horizontal is: 0 ≤φ≤90 deg. Based upon the analysis of physical model and experimental measurements several new experimental non-dimensional formulas are proposed:The influence of aspect ratio on heat transfer is discussed especially. It is found that the influences of aspect ratio on heat transfer in different ranges of aspect ratio are different. It is more important in the range of low aspect ratio. In this situation the non-dimensional formula must be presented as a function of (Ra·cosφ) and aspect ratio. The recommended relationships (12), (13), (14) and (15) can be used for design of solar collectors.更多还原