Novel Methods for Void Fraction Measurements by Means of Single-Beam Gamma-Densitometry

Abstract:

Gamma densitometry is a widespread nonintrusive method for measuring the void fraction among all the methods. Void fraction is a fundamental parameter and generally obtained by the logarithmic and linear equations by means of single-beam gamma-densitometry. However, using these two equations in large diameter pipeline is a hard goal to reach because of the limitation of the radioactive source. In this paper, we proposed a formula for the void fraction measurements in large diameter pipeline and this formula can be also utilized in small diameter pipeline. Deviations between the calculated and actual void fraction of the methods in this paper are demonstrated. The theoretical errors of the new formulae are relatively insignificant in comparison to the logarithmic and linear equations. The method for large diameter pipe has even a smaller theoretical error than multi-beam gamma-densitometry. Disadvantages of the logarithmic equation are analyzed and the modification of the void fraction measurement formulae is proved to be progressive in mathematics. We discussed the simplifications in the novel methods and they have negligible effect on the measurements. Measurement positions and areas are optimized based on the theoretical deduction. In addition, we formulated the experimental requirements of different void fraction expressions.

• Periodical: Applied Mechanics and Materials (Volumes 568-570)
• Pages: 59-64
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.568-570.59
• Online since: June 2014
• Authors: Jia Ji Li*, Chang Qi Yan, Xi Chuan Li
• Keywords: Measurement Principle, Single-Beam Gamma-Densitometry, Two-Phase Flow, Void Fraction

References

[1] G.F. Hewitt: Measurement of Two-Phase-FlowParameters, New York. (1978).

[2] R.T. Lahey, S. Banerjee: Advances in Nuclear Science Technology. Vol. 13(1980), P227-401.

[3] P. Stahl, P.R.V. Rohr: Exp. Therm. Fluid Sci. Vol. 28(2004), P533-544.

[4] J. Chaouki, F. Larachi, M. Dudukovic: Non-invasive Monitoring ofMultiphaseFlows. Elsevier, Amsterdam. (1997).

[5] M. Petrick B.S. Swanson: Rev. Sci. Instrum. Vol. 29(1958), P1079-1085.

[6] E. Abro, G.A. Johansen: FlowMeas. Instrum. Vol. 10(1999), P 99-108.

[7] T.K. Wang H.M. Liu: IEEE TRANS. on Nucl. Sci. Vol. 40(1993), P669-674.

[8] T. K. Thiyagarajan, P. Satyamurthy, et. al: Meas. Sci. Technol. Vol. 2(1991), P 69-74.

[9] S.A. Tjugum, J. Frieling, et. al: Nucl. Instrum. MethodsPhys. Res., B 197(2002), P301–309.