Determination of heat transfer coefficients in steam turbines

A method for the determination of heat transfer coefficients is described which is particularly suited for measurements inside steam turbine cylinders and buckets. The heat transfer coefficients are derived from the temperature frequency characteristics of the walls. Correlations are made between the time-dependent fluid temperature and the corresponding signal received by a detector just below the wall's surface. The natural stochastic temperature variation within a steam turbine can be used as test signal. Measurements in a 2 Megawatt steam turbine demonstrate, that the signal's power density is sufficiently high and the attenuation low within the important frequency range of 1/s ? ω? 10/s. The experimental verification of the method in a steam tunnel showed good results.