在轴流风机和离心风机上做的大量实验已经证明,风机入口和出口管道断面上空气温度的变化很小。于是,测定通过风机的空气流温度增量能很容易达到±0.05°F左右的精度。这样,就可以根据此温度增量及压力升高量来确定风机效率。用这个方法确定风机效率不需要测定空气流量,其精确性和用流量法确定风机效率一样高。一、用温度测定法确定风机效率的理论基础 Extensive experiments on axial fans and centrifugal fans have demonstrated that the air temperature changes at the fan inlet and outlet duct sections are small. Thus, measuring the temperature increase of the air flow through the fan can easily achieve an accuracy of about ±0.05°F. In this way, the fan efficiency can be determined based on this temperature increase and pressure increase. Using this method to determine the efficiency of the fan does not require the determination of the air flow, the accuracy of which is as high as the efficiency of the fan using the flow method. First, use the temperature measurement method to determine the theoretical basis of fan efficiency