Full Surface Local Heat Transfer Coefficient Measurements in a Model of an Integrally Cast Impingement Cooling Geometry

1998 ◽  
Vol 120 (1) ◽  
pp. 92-99 ◽  
Author(s):  
D. R. H. Gillespie ◽  
Z. Wang ◽  
P. T. Ireland ◽  
S. T. Kohler
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Local Heat Transfer Coefficient ◽  
Target Plate ◽  
Impingement Cooling ◽  
Impingement Plate

Cast impingement cooling geometries offer the gas turbine designer higher structural integrity and improved convective cooling when compared to traditional impingement cooling systems, which rely on plate inserts. In this paper, it is shown that the surface that forms the jets contributes significantly to the total cooling. Local heat transfer coefficient distributions have been measured in a model of an engine wall cooling geometry using the transient heat transfer technique. The method employs temperature-sensitive liquid crystals to measure the surface temperature of large-scale perspex models during transient experiments. Full distributions of local Nusselt number on both surfaces of the impingement plate, and on the impingement target plate, are presented at engine representative Reynolds numbers. The relative effects of the impingement plate thermal boundary condition and the coolant supply temperature on the target plate heat transfer have been determined by maintaining an isothermal boundary condition at the impingement plate during the transient tests. The results are discussed in terms of the interpreted flow field.

Full Surface Local Heat Transfer Coefficient Measurements in a Model of an Integrally Cast Impingement Cooling Geometry

1996 ◽  
Author(s):  
David R. H. Gillespie ◽  
Zuolan Wang ◽  
Peter T. Ireland ◽  
S. Toby Kohler
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Local Heat Transfer Coefficient ◽  
Target Plate ◽  
Impingement Cooling ◽  
Impingement Plate

Cast impingement cooling geometries offer the gas turbine designer higher structural integrity and improved convective cooling when compared to traditional impingement cooling systems which rely on plate inserts. In this paper, it is shown that the surface which forms the jets contributes significantly to the total cooling. Local heat transfer coefficient distributions have been measured in a model of an engine wall cooling geometry using the transient heat transfer technique. The method employs temperature sensitive liquid crystals to measure the surface temperature of large scale perspex models during transient experiments. Full distributions of local Nusselt number on both surfaces of the impingement plate, and on the impingement target plate are presented at engine representative Reynolds numbers. The relative effects of the impingement plate thermal boundary condition and the coolant supply temperature on the target plate heat transfer has been determined by maintaining an isothermal boundary condition at the impingement plate during the transient tests. The results are discussed in terms of the interpreted flow field.

The Relative Performance of External Casing Impingement Cooling Arrangements for Thermal Control of Blade Tip Clearance

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Myeonggeun Choi ◽  
David M. Dyrda ◽  
David R. H. Gillespie ◽  
Orpheas Tapanlis ◽  
Leo V. Lewis
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Operating Conditions ◽  
Local Heat Transfer Coefficient ◽  
Tip Clearance ◽  
Local Cooling ◽  
Impingement Cooling

As a key way of improving jet engine performance, a thermal tip clearance control system provides a robust means of manipulating the closure between the casing and the rotating blade tips, reducing undesirable tip leakage flows. This may be achieved using an impingement cooling scheme on the external casing. Such systems can be optimized to increase the contraction capability for a given casing cooling flow. Typically, this is achieved by changing the cooled area and local casing features, such as the external flanges or the external cooling geometry. This paper reports the effectiveness of a range of impingement cooling arrangements in typical engine casing closure system. The effects of jet-to-jet pitch, number of jets, and inline and staggered alignment of jets on an engine representative casing geometry are assessed through comparison of the convective heat transfer coefficient distributions as well as the thermal closure at the point of the casing liner attachment. The investigation is primarily numerical, however, a baseline case has been validated experimentally in tests using a transient liquid crystal technique. Steady numerical simulations using the realizable k–ε, k–ω SST, and EARSM turbulence models were conducted to understand the variation in the predicted local heat transfer coefficient distribution. A constant mass flow rate was used as a constraint at each engine condition, approximately corresponding to a constant feed pressure when the manifold exit area is constant. Sets of local heat transfer coefficient data generated using a consistent modeling approach were then used to create reduced order distributions of the local cooling. These were used in a thermomechanical model to predict the casing closure at engine representative operating conditions.

The Relative Performance of External Casing Impingement Cooling Arrangements for Thermal Control of Blade Tip Clearance

2015 ◽  
Author(s):  
Myeonggeun Choi ◽  
David M. Dyrda ◽  
David R. H. Gillespie ◽  
Orpheas Tapanlis ◽  
Leo V. Lewis
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Operating Conditions ◽  
Local Heat Transfer Coefficient ◽  
Tip Clearance ◽  
Local Cooling ◽  
Impingement Cooling

As a key way of improving jet engine performance, a thermal tip clearance control system provides a robust means of manipulating the closure between the casing and the rotating blade tips, reducing undesirable tip leakage flows. This may be achieved using an impingement cooling scheme on the external casing. Such systems can be optimized to increase the contraction capability for a given casing cooling flow. Typically this is achieved by changing the cooled area, local casing features such as the external flanges, or the external cooling geometry. This paper reports the effectiveness of a range of impingement cooling arrangements in typical engine casing closure system. The effects of jet-to-jet pitch, number of jets, inline and staggered alignment of jets, on an engine representative casing geometry are assessed through comparison of the convective heat transfer coefficient distributions as well as the thermal closure at the point of the casing liner attachment. The investigation is primarily numerical, however, a baseline case has been validated experimentally in tests using a transient liquid crystal technique. Steady numerical simulations using the realizable k-ε, k-ω SST and EARSM turbulence models were conducted to understand the variation in the predicted local heat transfer coefficient distribution. Constant mass flow rate was used as a constraint at each engine condition, this approximately pertaining to a constant feed pressure when the manifold exit area is constant. Sets of local heat transfer coefficient data generated using a consistent modelling approach were then used to create reduced order distributions of the local cooling. These were used in a thermo-mechanical model to predict the casing closure at engine representative operating conditions.

scholarly journals Detailed Measurements of Local Heat Transfer Coefficient and Adiabatic Wall Temperature Beneath an Array of Impinging Jets

1993 ◽  
Author(s):  
Kenneth W. Van Treuren ◽  
Zuolan Wang ◽  
Peter T. Ireland ◽  
Terry V. Jones
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Wall Temperature ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Impinging Jets ◽  
Local Heat Transfer Coefficient ◽  
Target Plate ◽  
Adiabatic Wall

A transient method of measuring the local heat transfer under an array of impinging jets has been developed. The use of a temperature sensitive coating consisting of three encapsulated thermochromic liquid crystal materials has allowed the calculation of both the local adiabatic wall temperature and the local heat transfer coefficient over the complete surface of the target plate. The influence of the temperature of the plate through which the impingement gas flows on the target plate heat transfer has been quantified. Results are presented for a single inline array configuration over a range of jet Reynolds numbers.

Detailed Measurements of Local Heat Transfer Coefficient and Adiabatic Wall Temperature Beneath an Array of Impinging Jets

1994 ◽  
Vol 116 (3) ◽  
pp. 369-374 ◽  
Author(s):  
K. W. Van Treuren ◽  
Z. Wang ◽  
P. T. Ireland ◽  
T. V. Jones
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Wall Temperature ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Impinging Jets ◽  
Local Heat Transfer Coefficient ◽  
Target Plate ◽  
Adiabatic Wall

A transient method of measuring the local heat transfer under an array of impinging jets has been developed. The use of a temperature-sensitive coating consisting of three encapsulated thermochromic liquid crystal materials has allowed the calculation of both the local adiabatic wall temperature and the local heat transfer coefficient over the complete surface of the target plate. The influence of the temperature of the plate through which the impingement gas flows on the target plate heat transfer has been quantified. Results are presented for a single in-line array configuration over a range of jet Reynolds numbers.

Local and Average Heat Transfer Characteristics for a Disk Situated Perpendicular to a Uniform Flow

1985 ◽  
Vol 107 (2) ◽  
pp. 321-326 ◽  
Author(s):  
E. M. Sparrow ◽  
G. T. Geiger
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Stagnation Point ◽  
Radial Distance ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Local Heat Transfer Coefficient ◽  
Average Heat ◽  
Radial Profiles

Wind tunnel experiments were performed to determine both the average heat transfer coefficient and the radial distribution of the local heat transfer coefficient for a circular disk facing a uniform oncoming flow. The experiments covered the range of Reynolds numbers Re from 5000 to 50,000 and were performed using the naphthalene sublimation technique. To complement the experiments, an analysis incorporating both potential flow theory and boundary layer theory was used to predict the stagnation point heat transfer. The measured average Nusselt numbers definitively resolved a deep disparity between information from the literature and yielded the correlation Nu = 1.05 Pr0.36 Re1/2. The radial distributions of the local heat transfer coefficient were found to be congruent when they were normalized by Re1/2. Furthermore, the radial profiles showed that the local coefficient takes on its minimum value at the stagnation point and increases with increasing radial distance from the center of the disk. At the outer edge of the disk, the coefficient is more than twice as large as that at the stagnation point. The theoretical predictions of the stagnation point heat transfer exceeded the experimental values by about 6 percent. This overprediction is similar to that which occurs for cylinders and spheres in crossflow.

Sign in / Sign up

Export Citation Format

Share Document