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室外热环境的研究热度越来越高,室外空气温度的精确测试对其研究具有重大影响。百叶箱被认为是室外空气温度测量中的标准仪器。但由于百叶箱体积过大、笨重难以携带,许多学者为了各自的研究目的或考虑成本自制了很多辐射罩。由于室外空气温度测试中采用不同的防辐射罩,得到的结果不同。为了提高室外空气温度测试的精度,减少防辐射罩所带来的误差,通过对某种常用的防辐射罩进行优化,为以后室外空气温度测试提供参考意见。通过问询、网上调查问卷等调研方法进行统计发现,最常用的低成本自制辐射罩为外表面为铝箔的水平圆筒。因此,选择该装置作为研究对象,考虑到风速和太阳辐射对室外空气温度测试的精度的影响,通过增强空气的对流作用,减少进入防辐射罩的太阳辐射,在实地实验测试中,通过改变圆筒长度与其直径比例和圆筒直径与仪器直径比例,改变内外表面的搭配,改变其安装角度,对该防辐射罩进行优化,为防辐射罩的优化提供意见。结果表明:1圆筒长度与其直径比例宜选择6倍。2圆筒直径与仪器直径比例宜选择6倍。3外表面不适宜选择吸收率过大的材料,内表面不适宜选择反射率过高、吸收率过小的材料。内外表面均优先选择白色。4水平筒的安装角度既要考虑太阳辐射,又要考虑风向。昼间测试时,分时段调整水平筒的角度的方案可行,建议每一时间段的调整范围在40°左右。
The study of outdoor thermal environment is getting more and more hot. The accurate test of outdoor air temperature has a significant impact on its research. The shutter is considered as a standard instrument for outdoor air temperature measurement. However, because of the oversize and unwieldyness of blinds, many scholars have made many radiation shields for their own research purposes or considering the cost. Different results were obtained due to the use of different radiation shields in the outdoor air temperature test. In order to improve the accuracy of the outdoor air temperature test and reduce the error caused by the radiation shield, some commonly used radiation shields are optimized to provide reference for later outdoor air temperature test. Statistics and surveys conducted through inquiries, online questionnaires and other research methods found that the most commonly used low-cost self-made radome is a horizontal cylinder with an aluminum foil on the outer surface. Therefore, the device was chosen as the research object, taking into account the influence of wind speed and solar radiation on the accuracy of the outdoor air temperature test, by increasing the air convection and reducing the solar radiation entering the radiation shield, in the field experiment, by changing the circle Tube length and diameter ratio and the diameter of the cylinder and the diameter of the instrument to change the mix of the inner and outer surface to change its installation angle of the radiation shield optimized for radiation shield optimization advice. The results show that: 1 Cylinder length and its diameter ratio should choose 6 times. 2 cylinder diameter and instrument diameter ratio should choose 6 times. 3, the surface is not suitable for selection Absorption rate is too large material, the internal surface is not suitable for the selection of high reflectivity, absorption rate is too small material. The inner and outer surfaces are preferred white. 4 horizontal tube installation angle to consider both solar radiation, but also to consider the wind direction. During the daytime test, it is feasible to adjust the angle of the horizontal barrel in different time periods. It is suggested that the adjustment range of each time period should be about 40 °.