| 摘要 |
PROBLEM TO BE SOLVED: To provide Reynolds number dependency of a coefficient of discharge of a nozzle to be tested by providing two acoustic velocity nozzles of which the coefficient of discharge is known in a base condition and a acoustic velocity nozzle of which the coefficient of discharge and the Reynolds number dependency are known when the nozzle is connected to a downstream side of the nozzles, and by measuring a pressure between these nozzles in the condition of connecting an unknown acoustic velocity nozzle to be tested. SOLUTION: The coefficient of discharge of No. 0 and No. 2 acoustic velocity nozzles is known at a base condition and the coefficient of discharge and Reynolds number dependency of No. 1 acoustic velocity nozzle when it is connected to a downstream side of the No. 0 and No. 2 acoustic velocity nozzles are known. A pressure P0 at an upstream side is not varied and a pressure P1 between the No. 0 and No. 1 nozzles is measured. Then, a directional control valve is switched, the No. 0 nozzle and a acoustic velocity nozzle to be tested are series-connected and a pressure P3 between these nozzles is measured. Further, the No. 2 nozzle is connected to the acoustic velocity nozzle to be tested instead of the No. 0 nozzle and pressures P5 and P7 are measured. Coefficientsα,βare obtained from the coefficient of discharge Cdt by an expression 1 to obtain Reynolds number dependency.
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