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Uncertainty Assessment of Gas Flow Measurement Using Multi-Point Pitot Tubes

다점 피토관을 이용한 기체 유량 측정의 불확도 평가

  • Yang, Inyoung (Engine system research team, Korea Aerospace Research Institute) ;
  • Lee, Bo-Hwa (Engine system research team, Korea Aerospace Research Institute)
  • 양인영 (한국항공우주연구원 엔진시스템연구팀) ;
  • 이보화 (한국항공우주연구원 엔진시스템연구팀)
  • Received : 2015.08.11
  • Accepted : 2016.01.11
  • Published : 2016.04.01

Abstract

Gas flow measurement in a closed duct was performed using multi-point Pitot tubes. Measurement uncertainty was assessed for this measurement method. The method was applied for the measurement of air flow into a gas turbine engine in an altitude engine test facility. 46 Pitot tubes, 15 total temperature Kiel probes and 9 static pressure tabs were installed in the engine inlet duct of inner diameter of 264 mm. Five tests were done in an airflow range of 2~10 kg/s. The flow was compressible and the Reynolds numbers were between 450,000 and 2,220,000. The measurement uncertainty was the highest as 6.1% for the lowest flow rate, and lowest as 0.8% for the highest flow rate. This is because the difference between the total and static pressures, which is also related to the flow velocity, becomes almost zero for low flow rate cases. It was found that this measurement method can be used only when the flow velocity is relatively high, e.g., 50 m/s. Static pressure was the most influencing parameter on the flow rate measurement uncertainty. Temperature measurement uncertainty was not very important. Measurement of boundary layer was found to be important for this type of flow rate measurement method. But measurement of flow non-uniformity was not very important provided that the non-uniformity has random behavior in the duct.

Keywords

References

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