【摘要】 黑体空腔理论在一些作者的努力下,逐渐趋于完善。目前,正注意空腔理论的实际应用。一些人曾把空腔和辐射检测器联系起来,用近似方法计算了积分空腔发射率,但由于晕光区的存在,这种计算结果和真值不同。实际应用中,检测器不可能离开空腔开口处太远,因此,当检测器位于离腔口某个有限距离时,精确计算空腔发射率是有意义的。本文给出一种精确计算带盖板的圆锥和圆柱空腔的积分发射率方法,并且使用电子计算机计算了数值结果,同时和别德福德(Bedford,R.E.)的近似方法做了比较。结果表明:当H=0和H→∞时(此处H表示从空腔口到检测器间的距离),对相同的空腔,两种方法得到的积分发射率ε~c结果一致。而当H在实用范围内,特别是对于表面发射率较低的短圆柱空腔和半顶角较大的圆锥空腔而言,两种方法得到的ε~c值是不同的。更多还原

【Abstract】 The blackbody theory are being perfected through the efforts of some scientists. Now attention is focused on the practical application of the cavity theory. Combining the cavity with the detector, some scientists have used an approximate method to calculate the integrated emissivity of the cavity, but the results will differ from the exact value because of the existence of the penumbral region. In practical application, the detector would not be too far from the aperture, so it is meaningful to calculate precisely the integrated emissivity of the cavity when the detector is at a finite distance from the aperture. In this paper, we give a precise method to calculate the integrated emissivity of baffled conical and cylindrical cavities. These equations have been solved by numerical integration techniques using a digital computer and the results have been compared with that of Bedford＇s approximate method. It shows that in the case of H=0 and H→∞(where H is the distance between a detector and the mouth of a cavity), the integrated emissivitiesεof the cavity of two methods tend to coincide for the same cavity. In other words, the differences in the values ofεfor two methods are evident in the H range of practical application, especially in the following cases: smaller values of surface emittance; shallow cylindrical cavities and conical cavities with larger half-angles.更多还原