Assessment and Development of Two Phase Turbulent Mixing Models for Subchannel Analysis Relevant to BWR
Affiliation(s)
1 Homi Bhabha National Institute, Mumbai, India. 2 Bhabha Atomic Research Centre, Reactor Engineering Division, Mumbai, India.
1 Homi Bhabha National Institute, Mumbai, India. 2 Bhabha Atomic Research Centre, Reactor Engineering Division, Mumbai, India.
ABSTRACT
Determination of turbulent mixing rate of two phase flow between neighboring subchannels is an important aspect of sub channel analysis in reactor rod bundles. Various models have been developed for two phase turbulent mixing rate between subchannels. These models show that turbulent mixing rate is strongly dependent on flow regimes; their validity was examined against specific or limited experiments. It is vital to evaluate these models by comparing the predicted two phase turbulent mixing rate with available experimental data conducted for various subchannel geometries and operating conditions. This paper describes evaluation of different models for two phase turbulent mixing rate for both gas and liquid phase against large range of experimental data which are obtained from various subchannel geometries. The results indicate that there is large discrepancy between the predicted and experimental data for turbulent mixing rate. This paper provides important shortcoming of the previous work and need for the development of a new model. In the view of this, a two phase flow model is presented, which predicts both liquid and gas phase turbulent mixing rate between adjacent sub channels of reactor rod bundles. The model presented here is for slug churn flow regime, which is dominant as compared to the other regimes like bubbly flow and annular flow regimes, since turbulent mixing rate is the highest in slug churn flow regime. The present model has been tested against low pressure and temperature air-water and high pressure and temperature steam-water experimental data found that it shows good agreement with available experimental data.
Determination of turbulent mixing rate of two phase flow between neighboring subchannels is an important aspect of sub channel analysis in reactor rod bundles. Various models have been developed for two phase turbulent mixing rate between subchannels. These models show that turbulent mixing rate is strongly dependent on flow regimes; their validity was examined against specific or limited experiments. It is vital to evaluate these models by comparing the predicted two phase turbulent mixing rate with available experimental data conducted for various subchannel geometries and operating conditions. This paper describes evaluation of different models for two phase turbulent mixing rate for both gas and liquid phase against large range of experimental data which are obtained from various subchannel geometries. The results indicate that there is large discrepancy between the predicted and experimental data for turbulent mixing rate. This paper provides important shortcoming of the previous work and need for the development of a new model. In the view of this, a two phase flow model is presented, which predicts both liquid and gas phase turbulent mixing rate between adjacent sub channels of reactor rod bundles. The model presented here is for slug churn flow regime, which is dominant as compared to the other regimes like bubbly flow and annular flow regimes, since turbulent mixing rate is the highest in slug churn flow regime. The present model has been tested against low pressure and temperature air-water and high pressure and temperature steam-water experimental data found that it shows good agreement with available experimental data.
Cite this paper
Sharma, M. and Nayak, A. (2014) Assessment and Development of Two Phase Turbulent Mixing Models for Subchannel Analysis Relevant to BWR. World Journal of Nuclear Science and Technology, 4, 195-207. doi: 10.4236/wjnst.2014.44025.
Sharma, M. and Nayak, A. (2014) Assessment and Development of Two Phase Turbulent Mixing Models for Subchannel Analysis Relevant to BWR. World Journal of Nuclear Science and Technology, 4, 195-207. doi: 10.4236/wjnst.2014.44025.
References
[1] Lahey Jr., R.T. andMoody, F.J. (1993) The Thermal Hydraulics of Boiling Water Nuclear Reactor. 2nd Edition, ANS, La Grange Park. [2] Walton, F.B. (1969) Turbulent Mixing Measurements for Single-Phase Air, Single-Phase Water and Two-Phase Air-Water Flows in Adjacent Triangular Subchannels. M.Sc. Thesis, Department of Chemical Engineering, University of Windsor, Windsor. [3] Rudzinski, K.F. (1970) Two-Phase Turbulent Mixing for Air-Water Flows in Adjacent Triangular Subchannels. M.Sc. Thesis, Department of Chemical Engineering, University of Windsor, Windsor. [4] Singh, K.S. (1972) Air-Water Turbulent Mixing in Simulated Rod Bundle Geometries. Ph.D. Thesis, Department of Chemical Engineering, University of Windsor, Windsor. [5] Kawahara, A., Sadatomi, M. and Sato, Y. (1997) Two-Phase Turbulent Mixing between Subchannels in a Simulated Rod Bundle Geometry—The Effect of the Number of Gaps between Subchannels. Proceedings of the 2nd JapaneseGerman Symposium on Multi-Phase Flow, Tokyo, 25-27 September 1997, 55-64. [6] Sadatomi, M., Kawahara, A., Kano, K. and Sumi, Y. (2004) Single and Two-Phase of Turbulent Mixing Rate between Adjacent Subchannels in a Vertical 2 × 3 Rod Array Channel. Nuclear Engineering and Design, 202, 27-38. [7] Kawahara, A., Sadatomi, M., Kudo, H. and Kano, K. (2006) Single and Two Phase Turbulent Mixing Rate between Subchannels in Triangle Tight Lattice Rod Bundle. JSME International Journal, Series B, 49, 287-295.
http://dx.doi.org/10.1299/jsmeb.49.287 [8] Bues, S.G. (1972) Two Phase Turbulent Mixing Model for Flow in Rod Bundle. Report WAPD-T-2438. Bettis Atomic Power Laboratory. Pittsburgh. [9] Kazimi, M.S. and Kelly, J.E. (1983) Formulation of Two Fluid Model for Mixing in LWR Bundle. In: Merilo, M., Ed., Thermal Hydraulics of Nuclear Reactor, ANS, Lagrange Park, Vol. 1, 433-439. [10] Kawahara, A., Sadatomi, M. and Sato, Y. (2000) Prediction of Turbulent Mixing Rate of Both Gas and Iquid Phases between Adjacent Subchannels in a Two Phase Slug Churn Flow. Nuclear Engineering and Design, 202, 27-38.
http://dx.doi.org/10.1016/S0029-5493(00)00300-9 [11] Carlucci, L.N., Hammouda, N. and Rowe, D.S. (2003) Two Phase Turbulent Mixing and Buoyancy Drift In Rod Bundle. Nuclear Engineering and Design, 227, 65-84.
http://dx.doi.org/10.1016/j.nucengdes.2003.08.003 [12] Rowe, D.S. and Angel, C.W. (1969) Cross Flow Mixing between Parallel Flow Channel during Boiling. Part III: Effect of Spacer on Mixing between Two Channels. Bettelle Nortwest, BNWL-371.
http://dx.doi.org/10.2172/4823782
[1] Lahey Jr., R.T. andMoody, F.J. (1993) The Thermal Hydraulics of Boiling Water Nuclear Reactor. 2nd Edition, ANS, La Grange Park. [2] Walton, F.B. (1969) Turbulent Mixing Measurements for Single-Phase Air, Single-Phase Water and Two-Phase Air-Water Flows in Adjacent Triangular Subchannels. M.Sc. Thesis, Department of Chemical Engineering, University of Windsor, Windsor. [3] Rudzinski, K.F. (1970) Two-Phase Turbulent Mixing for Air-Water Flows in Adjacent Triangular Subchannels. M.Sc. Thesis, Department of Chemical Engineering, University of Windsor, Windsor. [4] Singh, K.S. (1972) Air-Water Turbulent Mixing in Simulated Rod Bundle Geometries. Ph.D. Thesis, Department of Chemical Engineering, University of Windsor, Windsor. [5] Kawahara, A., Sadatomi, M. and Sato, Y. (1997) Two-Phase Turbulent Mixing between Subchannels in a Simulated Rod Bundle Geometry—The Effect of the Number of Gaps between Subchannels. Proceedings of the 2nd JapaneseGerman Symposium on Multi-Phase Flow, Tokyo, 25-27 September 1997, 55-64. [6] Sadatomi, M., Kawahara, A., Kano, K. and Sumi, Y. (2004) Single and Two-Phase of Turbulent Mixing Rate between Adjacent Subchannels in a Vertical 2 × 3 Rod Array Channel. Nuclear Engineering and Design, 202, 27-38. [7] Kawahara, A., Sadatomi, M., Kudo, H. and Kano, K. (2006) Single and Two Phase Turbulent Mixing Rate between Subchannels in Triangle Tight Lattice Rod Bundle. JSME International Journal, Series B, 49, 287-295.
http://dx.doi.org/10.1299/jsmeb.49.287 [8] Bues, S.G. (1972) Two Phase Turbulent Mixing Model for Flow in Rod Bundle. Report WAPD-T-2438. Bettis Atomic Power Laboratory. Pittsburgh. [9] Kazimi, M.S. and Kelly, J.E. (1983) Formulation of Two Fluid Model for Mixing in LWR Bundle. In: Merilo, M., Ed., Thermal Hydraulics of Nuclear Reactor, ANS, Lagrange Park, Vol. 1, 433-439. [10] Kawahara, A., Sadatomi, M. and Sato, Y. (2000) Prediction of Turbulent Mixing Rate of Both Gas and Iquid Phases between Adjacent Subchannels in a Two Phase Slug Churn Flow. Nuclear Engineering and Design, 202, 27-38.
http://dx.doi.org/10.1016/S0029-5493(00)00300-9 [11] Carlucci, L.N., Hammouda, N. and Rowe, D.S. (2003) Two Phase Turbulent Mixing and Buoyancy Drift In Rod Bundle. Nuclear Engineering and Design, 227, 65-84.
http://dx.doi.org/10.1016/j.nucengdes.2003.08.003 [12] Rowe, D.S. and Angel, C.W. (1969) Cross Flow Mixing between Parallel Flow Channel during Boiling. Part III: Effect of Spacer on Mixing between Two Channels. Bettelle Nortwest, BNWL-371.
http://dx.doi.org/10.2172/4823782