Heat-Flux Measurements for the Rotor of a Full-Stage Turbine: Part II—Description of Analysis Technique and Typical Time-Resolved Measurements

1986 ◽  
Vol 108 (1) ◽  
pp. 98-107 ◽  
Author(s):  
M. G. Dunn ◽  
W. K. George ◽  
W. J. Rae ◽  
S. H. Woodward ◽  
J. C. Moller ◽  
...  
Keyword(s):  
Thin Film ◽  
Heat Flux ◽  
Design Flow ◽  
Suction Surface ◽  
Stagnation Region ◽  
Time Resolved ◽  
Analysis Technique ◽  
Typical Time ◽  
Flux Measurements ◽  
Dominant Frequencies

This paper presents a detailed description of an analysis technique and an application of this technique to obtain time-resolved heat flux for the blade of a Garrett TFE 731-2 hp full-stage rotating turbine. A shock tube is used as a short-duration source of heated air and platinum thin-film gages are used to obtain the heat-flux measurements. To obtain the heat-flux values from the thin-film gage temperature histories, a finite-difference procedure has been used to solve the heat equation, with variable thermal properties. The data acquisition and the data analysis procedures are described in detail and then their application is illustrated for three midspan locations on the blade. The selected locations are the geometric stagnation point, 32.7 percent wetted distance on the suction surface, and 85.5 percent wetted distance on the suction surface. For these measurements, the turbine was operating at the design flow function and very near 100 percent corrected speed. The vane–blade axial spacing was consistent with the engine operating configuration. The results demonstrate that the magnitude of the heat-flux fluctuation resulting from the vane–blade interaction is large by comparison with the time-averaged heat flux at all locations investigated. The magnitude of the fluctuation is greatest in the stagnation region and decreases with increasing wetted distance along the surface. A Fourier analysis by FFT of a portion of the heat-flux record illustrates that the dominant frequencies occur at the wake-cutting frequency and its harmonics.

Effects of Wake Passing on Stagnation Region Heat Transfer

1990 ◽  
Vol 112 (3) ◽  
pp. 522-530 ◽  
Author(s):  
J. E. O’Brien
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Heat Flux ◽  
Windward Side ◽  
Stagnation Region ◽  
Time Resolved ◽  
Stagnation Line ◽  
Test Cylinder ◽  
Hot Film ◽  
Wake Passing

An experimental study is described in which both time-averaged and time-resolved effects of wake passing were measured in a cylinder stagnation region. The experiments were carried out in an annular-flow wind tunnel, which was fitted with a spoked-wheel wake generator. The cylindrical spokes produce wakes that simulate those shed from a turbine inlet guide vane. Time-averaged heat transfer results indicate an asymmetric distribution of heat transfer coefficient about the stagnation line, with higher heat transfer coefficients on the windward side (with respect to the bar-passing direction), which corresponds to the suction side of a turbine blade. This asymmetry is also reflected in the time-resolved heat transfer results, which were obtained using a test cylinder instrumented with platinum thin-film gages. Unsteady heat flux records reveal very large positive excursions (as much as a factor of three) in instantaneous heat flux during wake passing on the windward side of the cylinder and much smaller effects on the leeward side. Hot-film records in the cylinder stagnation region were also obtained by operating the thin-film gages in the constant-temperature mode. Spectra of these hot-film records indicate that vortex shedding is a major contributor to the unsteady buffeting of the test-cylinder boundary layer at circumferential stations located at both + 60 deg and − 60 deg from the stagnation line, but makes a very small contribution on the stagnation line itself.

Time-Averaged and Time-Resolved Heat Flux Measurements on a Turbine Stator Blade Using Two-Layered Thin-Film Gauges

2004 ◽  
Author(s):  
V. Iliopoulou ◽  
R. De´nos ◽  
N. Billiard ◽  
T. Arts
Keyword(s):  
Thin Film ◽  
Heat Flux ◽  
Numerical Algorithm ◽  
Temperature History ◽  
Layered System ◽  
Time Resolved ◽  
Flux Measurements ◽  
Stator Blade ◽  
Original Procedure ◽  
Layered Thin Film

This paper describes the steps undertaken to measure heat flux in a turbine tested in a blowdown windtunnel when using a two-layered thin film gauge array. The sensor consists of a nickel thermo resistor deposited onto a flexible polymide sheet that can be easily bounded on a substrate using double sided adhesive. The assembly constitutes a two-layered system. First, a numerical algorithm is proposed to extract the wall heat flux from the surface temperature history measured by the thin film gauge. It is very flexible and handles multi-layered systems. Then, an original procedure is proposed to determine the thermal properties and the thickness of the different layers. It uses the above numerical algorithm coupled with a minimization routine. The repeatability of the procedure is assessed. Finally, tests are processed according to the proposed method. The results are successfully compared with measurements performed with single-layered thin film gauges.

Phase-Resolved Heat-Flux Measurements on the Blade of a Full-Scale Rotating Turbine

1989 ◽  
Vol 111 (1) ◽  
pp. 8-19 ◽  
Author(s):  
M. G. Dunn ◽  
P. J. Seymour ◽  
S. H. Woodward ◽  
W. K. George ◽  
R. E. Chupp
Keyword(s):  
Heat Flux ◽  
Flux Distribution ◽  
Design Flow ◽  
Heat Flux Distribution ◽  
Time Resolved ◽  
Pressure Surface ◽  
Flux Data ◽  
Heated Air ◽  
Cutting Frequency ◽  
Flux Measurements

This paper presents detailed phase-resolved heat-flux data obtained on the blade of a Teledyne 702 HP full-stage rotating turbine. A shock tube is used as a short-duration source of heated air and platinum thin-film gages are used to obtain the heat-flux measurements. Results are presented along the midspan at several locations on the blade suction and pressure surfaces from the stagnation point to near the trailing edge. For these measurements, the turbine was operating at the design flow function and at 100 percent corrected speed. Results are presented for the design vane/blade spacing (0.19 Cs) and at a wide spacing (0.50 Cs). Data are also presented illustrating the phase-resolved blade heat-flux distribution with upstream cold gas injection from discrete holes on the vane surface. The results illustrate that several successive passages can be superimposed upon each other and that a heat-flux pattern can be determined within the passage. A Fourier analysis of the heat-flux record reveals contributions from the fundamental and first harmonic of the passage cutting frequency. Time-resolved surface pressure data obtained on the blade pressure surface are compared with heat-flux data.

Phase and Time-Resolved Measurements of Unsteady Heat Transfer and Pressure in a Full-Stage Rotating Turbine

1989 ◽  
Author(s):  
M. G. Dunn
Keyword(s):  
Heat Flux ◽  
Static Pressure ◽  
Pressure Ratio ◽  
Rotor Blades ◽  
Design Flow ◽  
Design Stage ◽  
Unsteady Heat Transfer ◽  
Time Resolved ◽  
Time Histories ◽  
Flux Measurements

This paper presents detailed phase-resolved heat-flux data obtained on rotor blades and a comparison of simultaneously obtained time-resolved heat-flux and static pressure data obtained on the stationary shroud of a Garrett TFE 731-2 HP full-stage rotating turbine. A shock tube is used to generate a short-duration source of heated and pressurized air and platinum thin-film gages are used to obtain heat-flux measurements. Blade results are presented at several selected blade locations. Shroud surface pressure and heat-flux time histories are presented for comparable locations relative to the blade position. For these measurements, the turbine was operating at the design flow function, the design stage pressure ratio, and at 100% corrected speed.

Time-Averaged and Time-Resolved Heat Flux Measurements on a Turbine Stator Blade Using Two-Layered Thin-Film Gauges

2004 ◽  
Vol 126 (4) ◽  
pp. 570-577 ◽  
Author(s):  
V. Iliopoulou ◽  
R. De´nos ◽  
N. Billiard ◽  
T. Arts
Keyword(s):  
Thin Film ◽  
Heat Flux ◽  
Numerical Algorithm ◽  
Temperature History ◽  
Layered System ◽  
Time Resolved ◽  
Multilayered Systems ◽  
Flux Measurements ◽  
Stator Blade ◽  
Layered Thin Film

This paper describes the steps undertaken to measure heat flux in a turbine tested in a blowdown windtunnel when using a two-layered thin film gauge array. The sensor consists of a nickel thermoresistor deposited onto a flexible polyamide sheet that can be easily bounded on a substrate using double sided adhesive. The assembly constitutes a two-layered system. First, a numerical algorithm is proposed to extract the wall heat flux from the surface temperature history measured by the thin film gauge. It is very flexible and handles multilayered systems. Then, an original procedure is proposed to determine the thermal properties and the thickness of the different layers. It uses the above numerical algorithm coupled with a minimization routine. The repeatability of the procedure is assessed. Finally, tests are processed according to the proposed method. The results are successfully compared with measurements performed with single-layered thin film gauges.

Phase and Time-Resolved Measurements of Unsteady Heat Transfer and Pressure in a Full-Stage Rotating Turbine

1990 ◽  
Vol 112 (3) ◽  
pp. 531-538 ◽  
Author(s):  
M. G. Dunn
Keyword(s):  
Heat Flux ◽  
Static Pressure ◽  
Pressure Ratio ◽  
Rotor Blades ◽  
Design Flow ◽  
Design Stage ◽  
Unsteady Heat Transfer ◽  
Time Resolved ◽  
Time Histories ◽  
Flux Measurements

This paper presents detailed phase-resolved heat-flux data obtained on rotor blades and a comparison of simultaneously obtained time-resolved heat-flux and static pressure data obtained on the stationary shroud of a Garrett TFE 731-2 HP full-stage rotating turbine. A shock tube is used to generate a short-duration source of heated and pressurized air and platinum thin-film gages are used to obtain heat-flux measurements. Blade results are presented at several selected blade locations. Shroud surface pressure and heat-flux time histories are presented for comparable locations relative to the blade position. For these measurements, the turbine was operating at the design flow function, the design stage pressure ratio, and at 100 percent corrected speed.

A Comparison of Radiation Versus Convection Calibration of Thin-Film Heat Flux Gauges

1999 ◽  
Author(s):  
D. E. Smith ◽  
J. V. Bubb ◽  
O. Popp ◽  
T. E. Diller ◽  
Stephen J. Hevey
Keyword(s):  
Thin Film ◽  
Heat Flux ◽  
Surface Temperature ◽  
Temperature Response ◽  
Turbine Rotor ◽  
Separate Experiment ◽  
Measured Temperature ◽  
Conduction Model ◽  
Time Resolved ◽  
Turbine Rotor Blade

Abstract A transient, in-situ method was examined for calibrating thin-film heat flux gauges using experimental data generated from both convection and radiation tests. Also, a comparison is made between this transient method and the standard radiation substitution calibration technique. Six Vatell Corporation HFM-7 type heat flux gauges were mounted on the surface of a 2-D, first-stage turbine rotor blade. These gauges were subjected to radiation from a heat lamp and in a separate experiment to a convective heat flux generated by flow in a transonic cascade wind tunnel. A second set of convective tests were performed using jets of cooled air impinging on the surface of the gauges. Direct measurements were simultaneously taken of both the time-resolved heat flux and surface temperature on the blade. The heat flux input was used to predict a surface temperature response using a one-dimensional, semi-infinite conduction model into a substrate with known thermal properties. The sensitivities of the gauges were determined by correlating the semi-infinite predicted temperature response to the measured temperature response. A finite-difference code was used to model the penetration of the heat flux into the substrate in order to estimate the time for which the semi-infinite assumption was valid. The results from these tests showed that the gauges accurately record both the convection and radiation modes of heat transfer. The radiation and convection tests yielded gauge sensitivities which agreed to within ±11%.

Heat-Flux Measurements for the Rotor of a Full-Stage Turbine: Part I—Time-Averaged Results

1986 ◽  
Vol 108 (1) ◽  
pp. 90-97 ◽  
Author(s):  
M. G. Dunn
Keyword(s):  
Heat Flux ◽  
Flat Plate ◽  
Guide Vane ◽  
Flow Direction ◽  
Leading Edge ◽  
Present Calculation ◽  
Suction Surface ◽  
Pressure Surface ◽  
Good Comparison ◽  
Flux Measurements

This paper describes time-averaged heat-flux distributions obtained for the blade of a Garrett TFE 731-2 hp full-stage rotating turbine. Blade measurements were obtained both with and without injection. The injected gas was supplied from a separate reservoir and was directed into the turbine gas path via nozzle guide vane (NGV) pressure surface slots located at approximately 63 percent of the wetted distance. Blade heat-flux measurements were performed for two different injection gas temperatures, Tc/T0 = 0.53 and Tc/T0 = 0.82. A shock tube is used as a short-duration source of heated air to which the turbine is subjected and thin-film gages are used to obtain the heat-flux measurements. Results are presented along the blade in the flow direction at 10, 50, and 90 percent span for both the pressure and suction surfaces. A sufficient number of measurements were obtained to also present span-wise distributions. At approximately the 50 percent span location, two contoured inserts containing closely spaced gages were installed in the blade so that the leading-edge region distribution could be resolved in detail. The blade results are compared with predictions obtained using a flat-plate technique and with predictions obtained using a version of STAN 5. The results suggest that: (1) The suction surface laminar flat-plate prediction is in reasonable agreement with the data from the stagnation point up to approximately 10 percent of the wetted distance. Beyond 10 percent, the laminar prediction falls far below the data and the turbulent flat-plate prediction falls above the data by about 60 percent. The laminar portion of the STAN 5 prediction as configured for the present calculation does not provide good comparison with the data. However, the turbulent flat-plate boundary-layer portion of STAN 5 does provide reasonably good comparison with the data. On the pressure surface, the turbulent flat-plate prediction is in good agreement with the data, but the laminar flat-plate and the STAN 5 predictions fall far low. (2) The influence of upstream NGV injection is to significantly increase the local blade heat flux in the immediate vicinity of the leading edge; i.e., up to 20 percent wetted distance on the suction surface and up to 10 percent on the pressure surface. (3) The effect on local heat flux of increasing the coolant-gas temperature was generally less than 10 percent.

The Unsteady Effect of Passing Shocks on Pressure Surface Versus Suction Surface Heat Transfer in Film-Cooled Transonic Turbine Blades

2003 ◽  
Author(s):  
A. C. Smith ◽  
A. C. Nix ◽  
T. E. Diller ◽  
W. F. Ng
Keyword(s):  
Heat Transfer ◽  
Shock Wave ◽  
Heat Flux ◽  
Film Cooling ◽  
Turbine Blades ◽  
Surface Heat ◽  
Suction Surface ◽  
Time Resolved ◽  
Pressure Surface ◽  
Transonic Turbine

This paper documents the measurement of the unsteady effects of passing shock waves on film cooling heat transfer on both the pressure and suction surfaces of first stage transonic turbine blades with leading edge showerhead film cooling. Experiments were performed for several cooling blowing ratios with an emphasis on time-resolved pressure and heat flux measurements on the pressure surface. Results without film cooling on the pressure surface demonstrated that increases in heat flux were a result of shock heating (the increase in temperature across the shock wave) rather than shock interaction with the boundary layer or film layer. Time-resolved measurements with film cooling demonstrated that the relatively strong shock wave along the suction surface appears to retard coolant ejection there and causes excess coolant to be ejected from pressure surface holes. This actually causes a decrease in heat transfer on the pressure surface during a large portion of the shock passing event. The magnitude of the decrease is almost as large as the increase in heat transfer without film cooling. The decrease in coolant ejection from the suction surface holes did not appear to have any effects on suction surface heat transfer.

Demonstrating the Use of Thin Film Gauges for Heat Flux Measurements in ICEs: Measurements on an Inlet Valve in Motored Operation

2016 ◽  
Author(s):  
Thomas De Cuyper ◽  
Sam Bracke ◽  
Jolien Lavens ◽  
Stijn Broekaert ◽  
Kam Chana ◽  
...  
Keyword(s):  
Thin Film ◽  
Heat Flux ◽  
Inlet Valve ◽  
Flux Measurements
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