engleski

Generalized Correlations for Determining of Heat Transfer in Turbine Bearings and Annular Clearances

For the solving of different problems in designing of new and exploitation of the existing steam and gas turbines (e.g. determination of temperature fields, state of temperature deformations and stresses of turbine elements aim at determining of useful life of particular constructive elements, application of the expert systems for on-line control of technological processes in thermal power stations, etc.) it is necessary to perform the calculation of heat transfer on surfaces of particular constructive elements, among others also in turbine journal bearings and annular clearances between stator and rotor. For this purpose the values of convective heat transfer coefficients have to be known. The convective heat transfer coefficients in turbine bearings and annular clearances are most frequently determined on the basis of correlations obtained by means of experimental measurements, often without checking the possibility of their application in the individual case. In literature, there is a definite number of empirical correlations proposed by various researchers, which are mutually distinguished with regard to the range of change of the geometrical and gas-dynamics parameters and with regard to choosing physical properties. All this makes their application more difficult. Therefore, in the paper, the systematization of single empirical correlations from literature is performed first. After that the original generalized correlations, obtained by means of statistical analysis of calculation results by systematized single correlations are proposed. The original generalized correlations proposed in the paper ensure accuracy of calculations which satisfy engineering applications.

heat transfer; generalized correlations; turbine bearings; annular clearances

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