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作静医测量时,要求静压孔周围的气流受测量装置本身及其他装置的扰动尽可能小,这样才能较正确地测出气流的静压。在压力耙(或风速管耙)上,影响静压测量正确度的因素更多。 本文综合了一些实验结果,讨论了亚音速自由射流中压力耙外形尺寸的几个主要参数:1)静压孔到静庄管前缘的距离、2)静压孔到支持杆的距离、3)邻近管与静压管间的距离、4)静压孔与邻近管前缘的距离、和5)支持杆与喷咀口直径比,对静压测量的影响。依此而提出了设计具有最小静压测量误差且误差随M数变化很小的压力耙的依据,以供设计压力耙作参考。
For static medical measurements, it is required that the air flow around the static pressure hole be disturbed by the measuring device itself and other devices as small as possible so that the static pressure of the air flow can be measured more accurately. On pressure harrows (or wind-tube harrows), there are more factors that affect the accuracy of static pressure measurements. In this paper, we summarize some experimental results and discuss some main parameters of the external dimensions of pressure rakes in subsonic free jet: 1) the distance from the static pressure hole to the front of the static tube, 2) the distance from the static pressure hole to the support rod, 3 ) The distance between the adjacent tube and the static pressure tube, 4) the distance between the static pressure hole and the leading edge of the adjacent tube, and 5) the ratio of the diameter of the support rod to the nozzle orifice to the static pressure measurement. Based on this, the basis for designing a pressure rake with the smallest static pressure measurement error and small variation of the error with the M number is proposed for reference of the design pressure rake.