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| Method for the tractability of Quantity Value of Sonic Nozzles with Stagnation Pressure as Low as 10 kPa |
| LI Chun-hui1,SU Jin-you2,YUAN Shi-hui2,GAO Shan1,3,ZHOU Li-yuan1 |
1. National Institute of Metrology, Beijing 100029, China
2. Key Laboratory of High-altitude Simulation Technology, Mianyang, Sichuan 621024, China
3. College of Quality and Technical Supervision, Hebei University, Baoding, Hebei 071002, China |
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Abstract In order to solve the problem that the existing gas flow measurement calibration technology can not achieve the direct calibration of the air engines gas flow under low pressure operating conditions and the traceability of the quantity value, the method of direct calibration and quantity tracing of sonic nozzles under low stagnation pressure was studied. Firstly, four sonic nozzles with nominal throat diameter of 40 mm were tested under atmospheric pressure using the gas flow reference device of pVTt method. Secondly, based on five standard sonic nozzles, the real flow calibration of sonic nozzles with a minimum of 10 kPa stagnation pressure is achieved by using a series of sonic nozzles. Finally, the discharge coefficient measured is linearly matched with the square root reciprocal of the Reynolds number in the throat of nozzle. Based on the linear fitting results, the feasibility and accuracy of the method are verified.
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2018, Vol. 39 
