Prediction of risers’ tubes temperature in water tube boilers

Abstract A dynamic model is developed which enables the prediction of risers’ tubes temperature of water tube boilers under various operating conditions. The model is composed of fluid dynamics model representing the fluid flow in the drum-downcomer-riser loop and a dynamic thermal model of the riser’s temperature. The model gives a detailed account of the two-phase heat transfer process which takes place between the risers’ inner walls and the water–steam mixture flow inside the tubes. The model is used to simulate various operational scenarios of water tube boilers. Results of the simulation provide insight into the dynamic interactions of the boiler’s main variables including the drum pressure, water volume, steam quality and risers’ temperature. Such a model is useful in checking operational scenarios before their actual plant implementation, can be a basis for developing boiler start up procedures and online temperature predictions to prevent eminent tube overheating.

[1]  K. Gungor,et al.  A general correlation for flow boiling in tubes and annuli , 1986 .

[2]  U. N. Gaitonde,et al.  Modeling of a Coal-Fired Natural Circulation Boiler , 2007 .

[3]  V. V. Klimenko,et al.  A generalized correlation for two-phase forced flow heat transfer , 1988 .

[4]  Rüdiger Franke,et al.  Optimization of boiler start-up using a nonlinear boiler model and hard constraints , 2004 .

[5]  G. R. Hall,et al.  Correlation of forced convection boiling heat transfer data , 1982 .

[6]  V. V. Klimenko,et al.  A generalized correlation for two-phase forced flow heat transfer—second assessment , 1990 .

[7]  Mark O'Malley,et al.  A drum boiler model for long term power system dynamic simulation , 1999 .

[8]  Sangmin Choi,et al.  A model on water level dynamics in natural circulation drum-type boilers , 2005 .

[9]  Karl Johan Åström,et al.  Drum-boiler dynamics , 2000, Autom..

[10]  M. Shah.  Chart correlation for saturated boiling heat transfer: Equations and further study , 1982 .

[11]  N. C Markatos,et al.  Numerical analysis of one-dimensional, two-phase flow in a vertical cylindrical passage , 1982 .

[12]  D. Kirkcaldy,et al.  Analysis and computation of three-dimensional, transient flow and combustion through granulated propellants , 1983 .

[13]  G. Hewitt.  GAS-LIQUID FLOW , 2006 .

[14]  J. Taborek,et al.  Flow Boiling Heat Transfer in Vertical Tubes Correlated by an Asymptotic Model , 1992 .

[15]  G. Hewitt,et al.  Studies of Two-Phase Flow Patterns by Simultaneous X-Ray and Flash Photography , 1969 .

[16]  G. L. Shires,et al.  Process Heat Transfer , 1994 .

[17]  J. Thome,et al.  Convective Boiling and Condensation , 1972 .

[18]  A. Dukler,et al.  A model for predicting flow regime transitions in horizontal and near horizontal gas‐liquid flow , 1976 .

[19]  E. J. Adam,et al.  Dynamic simulation of large boilers with natural recirculation , 1999 .

[20]  S. Kandlikar.  A General Correlation for Saturated Two-Phase Flow Boiling Heat Transfer Inside Horizontal and Vertical Tubes , 1990 .

[21]  M. Ohadi,et al.  Review of available correlations for prediction of flow boiling heat transfer in smooth and augmented tubes , 1995 .

[22]  J. C. Chen.  Correlation for Boiling Heat Transfer to Saturated Fluids in Convective Flow , 1966 .