**Greek letters**

Identifying the flue-gas side heat transfer coefficients for various boiler loads using the inverse method, a simple mathematical model of the platen superheater can be developed and used

The proposed method of solution can be successfully applied to solve other inverse prob‐

)

K)

in the control system of the superheated steam temperature.

*h*1, *hg* heat transfer coefficient on the inner and outer tube surface, W/(m2

/s2

lems occurring in industrial practice.

256 Numerical Simulation - From Brain Imaging to Turbulent Flows

*fi i*-th measured steam temperature, K or °C

*cw* specific heat capacity, J/(kg K)

*k* turbulence kinetic energy, m2

*m*˙ steam mass flow rate, kg/s *n* outward normal, m

*n* number of unknowns parameters

*Pk* production rate of turbulence energy, kg/(m s3

*P*<sup>ω</sup> turbulent frequency production term, s/m2

*S* invariant measure of the strain rate, 1/s

)

 s2 )

*kw* tube wall thermal conductivity, W/(m K) *m* number of temperature measurements points

*F* weighting function *F*<sup>2</sup> blending function *h* specific enthalpy, J/kg

**I** identity matrix **J** Jacobian matrix

*p* pressure, Pa

*q*˙ heat flux, W/m2 *Q*˙ heat flow rate, W/m3

*S<sup>E</sup>* energy source, kg/(m s3

*S<sup>M</sup>* momentum source, kg/(m2

*T* fluid temperature, K or °C *Tg* flue-gas temperature

*u* steam velocity, m/s **U** vector of velocity

*Tw* tube wall temperature, K or °C

*r* radius, m

*t* time, s

**Nomenclature**

