风速,温度与相对湿度测量精度的关系研究（英文）

农产品产后干燥加工环境普遍采用干湿球测湿法测量空气相对湿度.在温,湿度控制室内,对风速v,温度t,相对湿度U进行试验,结果指出:口的下界为0.2 m·s-1;当v＞2.5 m·s-1后,按v-2.5 m·s-1计算不影响测量精度;t＜40℃时,干湿球系数A几乎不受t的影响;在40℃＜t＜70℃范围内,A值大体上与t的2/3次方成正比;f＞80℃以后,A与t的关系变得复杂.提出了40℃＜t＜70℃范围内A的计算公式.经验证,在0.2＜v＜4 m·s-1,40℃＜t＜70℃和30%＜U＜90%R.H范围内,使用此公式计算获得的相对湿度值,误差＜1.5%R.H.

Study on relationships of wind velocity, temperature and measurement precision of relative humidity

Psychrometric method is widely used to measure the air relative humidity in dryness processing of agricultural products.The experiments about the relationships of the wind velocity v,temperature t and relative humidity U were made in temperature-humidity controlling cabin.The results indicate that the dowm limit of v is 0.2 m·s-1 and has no influence on the measurement accuracy.regarding v as 2.5 m·s-1 when v＞2.5 m·s-1.The results also show that psychrometer constant A is hardly effected by the temperature when t＜40℃.and it is proportional to t2/3.within 40℃＜t＜70℃:The relationship of A and t becomes complication when t＞80℃.A formula about A is proposed within 40℃＜t＜70℃,and it is demonstrated that the error of the relative humidity calculated by this formula is less than 1.5%R.H,when 0.2＜v＜4 m·s-1,40℃＜t＜70℃and 30%＜U＜90%R.H.