辐射板对垂直壁面角系数的近似求解

Approximate Solution of Angle Factor from Radiant Panel to Vertical Surface

辐射空调房间内不同面之间的角系数对于精确求解辐射换热量、辐射空调负荷意义重大。使用边界积分法,计算了矩形有限面和其中心位置等高微元面对同一垂直壁面间的角系数,得到了壁面尺寸、辐射面高度及布置位置与角系数的函数关系。比对了矩形有限面与其中心位置的等高微元面对同一壁面的角系数。结果表明,微元面对垂直壁面的角系数与壁面宽高比、辐射面与壁面高度之比正相关,与距离负相关。得到了角系数与各影响因素的数学表达式;发现矩形有限面和其中心位置等高微元面对同一垂直面角系数差值小于3%,且差值随辐射面和壁面间距离增加而减小并趋近于零。因此可近似得到辐射板布置位置与其对垂直壁面角系数的关系。

The heat transfer and the load of radiant panel accurately needs was calculate to the angle factor between them firstly.At the beginning curve integral formula is used to derive the expression of angle factor from both infinitesimal area and rectangle area to a vertical surface.Then obtained the functional relationship between the size of surface or the radiant panel and angle factor was obtained.Angle factor is related to the width to height ratio of the surface and height of panel to the surface ratio and the distance.Compared the difference of angle factor between rectangular surface and infinitesimal area positioned on the symmetry axis of the surface with the same height,and then found that the difference is smaller than 3% in the worst condition.So the infinitesimal area positioned on the symmetry axis could be an alternative to rectangle area in angle factor calculation.So be get the relationship between the location the radiant panel placed and the angle factor could be got, furthermore it＆#39;s a simpler method to calculate the angle factor between rectangle areas.