A Study on the Propagation of Measurement Uncertainties into the Result on a Turbine Performance Test

  • Cho, Soo-Yong (Department of Mechanical and Aerospace Engineering Gyeongsang National University) ;
  • Park, Chanwoo (Department of Mechanical and Aerospace Engineering Gyeongsang National University)
  • Published : 2004.04.01

Abstract

Uncertainties generated from the individual measured variables have an influence on the uncertainty of the experimental result through a data reduction equation. In this study, a performance test of a single stage axial type turbine is conducted, and total-to-total efficiencies are measured at the various off-design points In the low pressure and cold state. Based on an experimental apparatus, a data reduction equation for turbine efficiency is formulated and six measured variables are selected. Codes are written to calculate the efficiency, the uncertainty of the efficiency, and the sensitivity of the efficiency uncertainty by each of the measured quantities. The influence of each measured variable on the experimental result is figured out. Results show that the largest uncertainty magnification factor (UMF) value is obtained by the inlet total pressure among the six measured variables, and its value is always greater than one. The UMF values of the inlet total temperature, the torque, and the RPM are always one. The uncertainty percentage contribution (UPC) of the RPM shows th, lowest influence on the uncertainty of the turbine efficiency, but the UPC of the torque has the largest influence to the result among the measured variables. These results are applied to find the correct direction for meeting an uncertainty requirement of the experimental result in the planning or development Phase of experiment, and also to offer ideas for preparing a measurement system in the planning phase.

Keywords

References

  1. Abernethy, R.B., Benedict, R.P. and Dcwdell, R.B., 1985, 'ASME Measurement Uncertainty,' J. of Fluids Engineering, Vol. 107, pp. 161-164 https://doi.org/10.1115/1.3242450
  2. Cho, S. Y., Yoon, E. S. and Choi, B. S., 2002, 'A Study on an Acial-Type 2-D Turbine Blade Shape for Reducing the Blade Profile Loss,' KSME Int. J., Vol. 16, No. 8, pp. 1154-1164
  3. Coleman, H. W. and Steels, W. G., 1987, 'Some Considerations in the Propagation of Bias and Precision Errors into an Experimental Results,' FED-Vol. 58, pp. 57-62
  4. Coleman, H. W. and Steels, W. G., 1995, 'Engineering Application of Uncertainty Analysis,' AIAA, J., Vol. 33, No. 10, pp. 1888-1896 https://doi.org/10.2514/3.12742
  5. Hudson, S. T. and Coleman, H. W., 1996, 'A Preliminary Assessment of Methods for Determining Turbine Efficiency,' AIAA 96-0101, Reno
  6. International Organization for Standardization, 1993, 'Guide to the Expression of Uncertainty in Measurement,' ISBN 92-67-10188-9, ISO, Geneva
  7. Kim, D.S. and Cho, S.Y., 2002, 'An Experimental Study of Incidence Angle Effect on 3-D Axial Type Turbine,' Trans of KSME (B), Vol. 26, No. 9, pp. 1291-1301
  8. Kline, S. J. and McClintock, F. A., 1953, 'Describing Uncertainties in Single-Sample Experiments,' Mech. Eng., Jan., pp. 3-8
  9. Kline, S. J., 1985, 'The Purposes of Uncertainty Analysis,' J. of Fluids Engineering, Vol. 107, pp. 153-160 https://doi.org/10.1115/1.3242449
  10. Moffat, R. J., 1982, 'Contributions to the Theory of Single-Sample Uncertainty Analysis,' J. of Fluids Engineering, Vol. 104, pp. 250-260 https://doi.org/10.1115/1.3241818
  11. Moffat, R. J., 1985, 'Using Uncertainty Analysis in the Planning of an Experiment,' J. of Fluids Engineering, Vol. 107, pp. 173-178 https://doi.org/10.1115/1.3242452
  12. Moffat, R. J., 1988, 'Describing the Uncertainties in Experimental Results,' Experimental Thermal and Fluid Science, Vol. 1, pp. 3-17 https://doi.org/10.1016/0894-1777(88)90043-X
  13. Steels, W. G. and Coleman, W. G., 1987, 'Use of Uncertainty Analysis in the Planning and Design of an Experiment,' FED-Vol. 58, pp. 63-67