新オリフィス流量計

抄録

As the lower pressure of hitherto used crifice flowmeter, with vena contracta tap or corner tap, pressure at the position of the vena contracta is taken approximately. But the phenomenon of the vena contracta is so complicated that the interchangeability of orifice flowmeter can hardly be obtained without the strict standardization of the orifice plate.
The new orifice flowmeter here reported has the taps within the orifice plate itself, and the pressure at the orifice plate itself is taken instead of the pressure at the vena contracta. The profiles of these plates are shown in Fig. 2. The upstream side of the orifice hole is rounded with five kinds of radius, i, e., r=0, 0.5, 1.0, 1.5 and 2.0 mm. The experimental results, in the region of Reynolds number 3×10³_??_3×10⁴, show that the orifice with 1.5 mm radius has a better interchangeability than other orifice plates, and that the flowmeter enables us to measure the flow rate regardless of vena contracta as it is expected.