Novel Two-Dimensional Transient Heat Conduction Calculation in a Cooled Rotor: Ventilation Preheating—Blow-Down Flux

This contribution presents an alternative to classical data reduction techniques to measure the heat transfer using thin-film gauges. A finite-element model of the two-dimensional unsteady heat conduction equation is solved in the cross-sectional area of a metallic airfoil bounded with a polyamide sheet on which thermal sensors are deposited. This novel methodology allows capturing all 2D heat conduction effects that are irremediably neglected with the 1D data reduction technique. The application of this technique in a compression tube facility allows an exact evaluation of the initial wall heat flux into cooled rotor blades. During the spinning-up period, the rotor is spun up to nearly its nominal speed (from 0 rpm to 6200 rpm) resulting in preheating due to drag losses. The long duration of this experiment (∼450 s) and the magnitude of the wall temperature increase result in significant 2D conduction effects that are not accounted for using the 1D approach. In addition, short-duration experiments confirm the existence of 2D effects at smaller time scales (∼0.5 s), as well as the influence of the initial nonuniform temperature distribution in the rotor blade. The resulting flux with such an initial condition appears to be the superposition of the wall heat fiux at the end of the spinning up before the test and the flux due to the blow-down itself.

[1]  Y. Saad,et al.  GMRES: a generalized minimal residual algorithm for solving nonsymmetric linear systems , 1986 .

[2]  T. Yasa,et al.  Determination of the Efficiency of a Cooled HP Turbine in a Compression Tube Facility , 2006 .

[3]  R. Dénos,et al.  DATA REDUCTION AND THERMAL PRODUCT DETERMINATION FOR SINGLE AND MULTI-LAYERED SUBSTRATES THIN-FILM GAUGES , 2002 .

[4]  Shengmin Guo,et al.  The development of a new direct-heat-flux gauge for heat-transfer facilities , 2000 .

[5]  J. Kestin,et al.  The Influence of Turbulence on Mass Transfer From Cylinders , 1971 .

[6]  M. L. G. Oldfield,et al.  New Heat Transfer Gages for Use on Multilayered Substrates , 1986 .

[7]  R. I. Vachon,et al.  The effect of turbulence on heat transfer from heated cylinders , 1975 .

[8]  Tony Arts,et al.  Aero-Thermal Performance of a Two-Dimensional Highly Loaded Transonic Turbine Nozzle Guide Vane: A Test Case for Inviscid and Viscous Flow Computations , 1992 .

[9]  Alan H. Epstein,et al.  High-frequency response heat-flux gauge , 1986 .

[10]  Michael G. Dunn,et al.  Measurement of Heat Flux and Pressure in a Turbine Stage , 1982 .

[11]  N. Billiard,et al.  Time-Averaged and Time-Resolved Heat Flux Measurements on a Turbine Stator Blade Using Two-Layered Thin-Film Gauges , 2004 .

[12]  P. Lettieri,et al.  An introduction to heat transfer , 2007 .

[13]  Guillermo Paniagua,et al.  Thermocouple Probes for Accurate Temperature Measurements in Short Duration Facilities , 2002 .

[14]  Arnold M. Kuethe,et al.  Effects of Turbulence on Laminar Skin Friction and Heat Transfer , 1966 .

[15]  Michael G. Dunn,et al.  Turbine Heat Flux Measurements: Influence of Slot Injection on Vane Trailing Edge Heat Transfer and Influence of Rotor on Vane Heat Transfer , 1985 .

[16]  T. V. Jones,et al.  Heat-transfer measurements in short-duration hypersonic facilities , 1973 .

[17]  Terry V. Jones,et al.  Radial conduction effects in transient heat transfer experiments , 1997 .

[18]  Tony Arts,et al.  Unsteady Rotor Heat Transfer in a Transonic Turbine Stage , 2002 .

[19]  M. L. G. Oldfield,et al.  The theory of advanced multi-layer thin film heat transfer gauges , 1987 .

[20]  Singiresu S. Rao.  The finite element method in engineering , 1982 .