Research oriented on identification of operating states variations with the application of mathematical models of thermal processes has been developed in the field of energy processes diagnostics. Simple models, characterised by short calculation time, are necessary for thermal diagnostics needs. Such models can be obtained using empirical modelling methods. Good results brings the construction of analytical model with auxiliary empirical built-in functions. The paper presents a mathematical model of a steam-water cycle containing mass and energy balances and semiempirical models of steam expansion line in turbine as well as heat transfer in exchangers. A model of steam expansion line in a turbine is worked out with the application of a steam flow capacity equation and an internal efficiency of process equation for each group of stages for the analysed turbine. A model of a heat exchanger contains energy balance and the relation describing heat transfer in an exchanger, proposed by Beckman. Estimation of empirical equations coefficients was realised with the application of special and reliable measurements. Estimation criterion was a weighted relative sum of the remainder squares. There are exemplary calculations results presented in the final part of paper.

JO - Archives of Thermodynamics L1 - http://rhis.czasopisma.pan.pl/Content/94146/PDF/11_paper.pdf L2 - http://rhis.czasopisma.pan.pl/Content/94146 PY - 2010 IS - No 3 September EP - 183 KW - CHP unit KW - Steam-water cycle KW - Bleed-condensing turbine KW - Semi-empirical model A1 - Szapajko, Grzegorz A1 - Rusinowski, Henryk PB - The Committee on Thermodynamics and Combustion of the Polish Academy of Sciences JF - Archives of Thermodynamics SP - 165 T1 - Mathematical modelling of steam-water cycle with auxiliary empirical functions application DA - 2010 UR - http://rhis.czasopisma.pan.pl/dlibra/docmetadata?id=94146 DOI - 10.2478/v10173-010-0021-x ER -