Double Wall Cooling of a Full Coverage Effusion Plate With Cross Flow Supply Cooling and Main Flow Pressure Gradient

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Phil Ligrani ◽  
Zhong Ren ◽  
Sneha Reddy Vanga ◽  
Christopher Allgaier ◽  
Federico Liberatore ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Cross Flow ◽  
Main Flow ◽  
Main Stream ◽  
Cold Side ◽  
Flow Area ◽  
Blowing Ratio ◽  
Full Coverage ◽  
Contraction Ratio ◽  
Double Wall

Experimentally measured results are presented for different experimental conditions for a test plate with double wall cooling, composed of full-coverage effusion-cooling on the hot side of the plate, and cross-flow cooling on the cold side of the plate. The results presented are different from those from past investigations, because of the addition of a significant mainstream pressure gradient. Main stream flow is provided along a passage with a contraction ratio of 4, given by the ratio upstream flow area, to downstream flow area. With this arrangement, local blowing ratio decreases significantly with streamwise development along the test section, for every value of initial blowing ratio considered, where this initial value is determined at the most upstream row of effusion holes. Experimental data are given for a sparse effusion hole array. The experimental results are provided for mainstream Reynolds numbers of 92,400–96,600, and from 128,400 to 135,000, and initial blowing ratios of 3.3–3.6, 4.4, 5.2, 6.1–6.3, and 7.3–7.4. Results illustrate the effects of blowing ratio for the hot side and the cold side of the effusion plate. Of particular interest are values of line-averaged film cooling effectiveness and line-averaged heat transfer coefficient, which are generally different for contraction ratio of 4, compared to a contraction ratio of 1, because of different amounts and concentrations of effusion coolant near the test surface. In regard to cold-side measurements on the crossflow side of the effusion plate, line-averaged Nusselt numbers for contraction ratio 4 are often less than values for contraction ratio 1, when compared at the same main flow Reynolds number, initial blowing ratio, and streamwise location.

Double Wall Cooling of a Full Coverage Effusion Plate With Cross Flow Supply Cooling and Main Flow Pressure Gradient

2018 ◽  
Author(s):  
Christopher Allgaier ◽  
Zhong Ren ◽  
Sneha Reddy Vanga ◽  
Phil Ligrani ◽  
Federico Liberatore ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Cross Flow ◽  
Main Flow ◽  
Main Stream ◽  
Cold Side ◽  
Flow Area ◽  
Blowing Ratio ◽  
Full Coverage ◽  
Contraction Ratio ◽  
Double Wall

Experimentally measured results are presented for different experimental conditions for a test plate with double wall cooling, comprised of full-coverage effusion-cooling on the hot-side of the plate, and cross-flow cooling on the cold-side of the plate. The results presented are different from those from past investigations, because of the addition of a significant mainstream pressure gradient. Main stream flow is provided along a passage with a contraction ratio of 4, given by the ratio upstream flow area, to downstream flow area. With this arrangement, local blowing ratio decreases significantly with streamwise development along the test section, for every value of initial blowing ratio considered, where this initial value is determined at the most upstream row of effusion holes. Experimental data are given for a sparse effusion hole array. The experimental results are provided for mainstream Reynolds numbers of 128400 to 135300, and initial blowing ratios of 3.6, 4.4, 5.2, 6.1–6.3, and 7.3–7.4. Results illustrate the effects of blowing ratio for the hot-side and the cold-side of the effusion plate. Of particular interest are values of line-averaged film cooling effectiveness and line-averaged heat transfer coefficient, which are generally different for contraction ratio of 4, compared to a contraction ratio of 1, because of different amounts and concentrations of effusion coolant near the test surface. In regard to cold-side measurements on the crossflow side of the effusion plate, line-averaged Nusselt numbers for contraction ratio 4 are often less than values for contraction ratio 1, when compared at the same main flow Reynolds number, initial blowing ratio, and streamwise location.

Double Wall Cooling of a Full Coverage Effusion Plate With Main Flow Pressure Gradient, Including Internal Impingement Array Cooling

2018 ◽  
Author(s):  
Sneha Reddy Vanga ◽  
Zhong Ren ◽  
Austin J. Click ◽  
Phil Ligrani ◽  
Federico Liberatore ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Pressure Gradient ◽  
Cross Flow ◽  
Main Flow ◽  
Blowing Ratio ◽  
Impingement Jet ◽  
Full Coverage ◽  
Spatially Resolved ◽  
Contraction Ratio ◽  
Effusion Hole

The present study provides new effusion cooling data for both surfaces of full coverage effusion cooling plate. For the effusion cooled surface, presented are spatially-resolved distributions of surface adiabatic film cooling effectiveness, and surface heat transfer coefficients (measured using transient techniques and infrared thermography). For the impingement cooled surface, presented are spatially-resolved distributions of surface Nusselt numbers (measured using steady-state liquid crystal thermography). To produce this cool side augmentation, impingement jet arrays at different jet Reynolds numbers, from 2720 to 11100, are employed. Experimental data are given for a sparse effusion hole array, with spanwise and streamwise impingement hole spacing such that coolant jet hole centerlines are located midway between individual effusion hole entrances. Considered are initial effusion blowing ratios from 3.3 to 7.5, with subsonic, incompressible flow. The velocity of the freestream flow which is adjacent to the effusion cooled boundary layer is increasing with streamwise distance, due to a favorable streamwise pressure gradient. Such variations are provided by a main flow passage contraction ratio CR of 4. Of particular interest are effects of impingement jet Reynolds number, effusion blowing ratio, and streamwise development. Also included are comparisons of impingement jet array cooling results with: (i) results associated with cross flow supply cooling with CR = 1 and CR = 4, and (ii) results associated with impingement supply cooling with CR = 1, when the mainstream pressure gradient is near zero. Overall, the present results show that, for the same main flow Reynolds number, approximate initial blowing ratio, and streamwise location, significantly increased thermal protection is generally provided when the effusion coolant is provided by an array of impingement cooling jets, compared to a cross flow coolant supply.

Double Wall Cooling of a Full-Coverage Effusion Plate With Main Flow Pressure Gradient, Including Internal Impingement Array Cooling

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Sneha Reddy Vanga ◽  
David Ritchie ◽  
Austin Click ◽  
Zhong Ren ◽  
Phil Ligrani ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Pressure Gradient ◽  
Main Flow ◽  
Hole Array ◽  
Blowing Ratio ◽  
Impingement Jet ◽  
Full Coverage ◽  
Spatially Resolved ◽  
Contraction Ratio ◽  
Effusion Hole

The present study provides new effusion cooling data for both the surfaces of the full-coverage effusion cooling plate. For the effusion-cooled surface, presented are spatially resolved distributions of surface adiabatic film cooling effectiveness and surface heat transfer coefficients (measured using transient techniques and infrared thermography). For the impingement-cooled surface, presented are spatially resolved distributions of surface Nusselt numbers (measured using steady-state liquid crystal thermography). To produce this cool-side augmentation, impingement jet arrays at different jet Reynolds numbers, from 2720 to 11,100, are employed. Experimental data are given for a sparse effusion hole array, with spanwise and streamwise impingement hole spacing such that coolant jet hole centerlines are located midway between individual effusion hole entrances. Considered are the initial effusion blowing ratios from 3.3 to 7.5, with subsonic, incompressible flow. The velocity of the freestream flow which is adjacent to the effusion-cooled boundary layer is increasing with streamwise distance, due to a favorable streamwise pressure gradient. Such variations are provided by a main flow passage contraction ratio CR of 4. Of particular interest are effects of impingement jet Reynolds number, effusion blowing ratio, and streamwise development. Also, included are comparisons of impingement jet array cooling results with: (i) results associated with crossflow supply cooling with CR = 1 and CR = 4 and (ii) results associated with impingement supply cooling with CR = 1, when the mainstream pressure gradient is near zero. Overall, the present results show that, for the same main flow Reynolds number, approximate initial blowing ratio, and streamwise location, significantly increased thermal protection is generally provided when the effusion coolant is provided by an array of impingement cooling jets, compared to a crossflow coolant supply.

Effects of Double Wall Cooling Configuration and Conditions on Performance of Full-Coverage Effusion Cooling

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Nathan Rogers ◽  
Zhong Ren ◽  
Warren Buzzard ◽  
Brian Sweeney ◽  
Nathan Tinker ◽  
...  
Keyword(s):  
Film Cooling ◽  
Cross Flow ◽  
Hole Array ◽  
Adiabatic Wall ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Full Coverage ◽  
Cooling Hole ◽  
Double Wall

Experimental results are presented for a double wall cooling arrangement which simulates a portion of a combustor liner of a gas turbine engine. The results are collected using a new experimental facility designed to test full-coverage film cooling and impingement cooling effectiveness using either cross flow, impingement, or a combination of both to supply the film cooling flow. The present experiment primarily deals with cross flow supplied full-coverage film cooling for a sparse film cooling hole array that has not been previously tested. Data are provided for turbulent film cooling, contraction ratio of 1, blowing ratios ranging from 2.7 to 7.5, coolant Reynolds numbers based on film cooling hole diameter of about 5000–20,000, and mainstream temperature step during transient tests of 14 °C. The film cooling hole array consists of a film cooling hole diameter of 6.4 mm with nondimensional streamwise (X/de) and spanwise (Y/de) film cooling hole spacing of 15 and 4, respectively. The film cooling holes are streamwise inclined at an angle of 25 deg with respect to the test plate surface and have adjacent streamwise rows staggered with respect to each other. Data illustrating the effects of blowing ratio on adiabatic film cooling effectiveness and heat transfer coefficient are presented. For the arrangement and conditions considered, heat transfer coefficients generally increase with streamwise development and increase with increasing blowing ratio. The adiabatic film cooling effectiveness is determined from measurements of adiabatic wall temperature, coolant stagnation temperature, and mainstream recovery temperature. The adiabatic wall temperature and the adiabatic film cooling effectiveness generally decrease and increase, respectively, with streamwise position, and generally decrease and increase, respectively, as blowing ratio becomes larger.

Double Wall Cooling of an Effusion Plate With Simultaneous Cross Flow and Impingement Jet Array Internal Cooling

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
David Ritchie ◽  
Austin Click ◽  
Phillip M. Ligrani ◽  
Federico Liberatore ◽  
Rajeshriben Patel ◽  
...  
Keyword(s):  
Heat Flux ◽  
Reynolds Number ◽  
Stream Flow ◽  
Cross Flow ◽  
Main Stream ◽  
Streamwise Location ◽  
Net Heat Flux ◽  
Contraction Ratio ◽  
The Cross ◽  
Double Wall

Considered is double wall cooling, with full-coverage effusion-cooling on the hot side of the effusion plate, and a combination of impingement cooling and cross flow cooling, employed together on the cold side of the effusion plate. Data are given for a main stream flow passage with a contraction ratio (CR) of 4 for main stream Reynolds numbers Rems and Rems,avg of 157,000–161,000 and 233,000–244,000, respectively. Hot-side measurements (on the main stream flow or hot side of the effusion plate) are presented, which are measured using infrared thermography. Using a transient thermal measurement approach, measured are spatially resolved distributions of surface adiabatic film cooling effectiveness, and surface heat transfer coefficient. For the same Reynolds number, initial blowing ratio (BR), and streamwise location, increased thermal protection is often provided when the effusion coolant is provided by the cross flow/impingement combination configuration, compared to the cross flow only supply arrangement. In general, higher adiabatic effectiveness values are provided by the impingement only arrangement, relative to the impingement/cross flow combination configuration, when compared at the same Reynolds number, initial BR, and x/de location. Data for one streamwise location of x/de = 60 show that the highest net heat flux reduction line-averaged net heat flux reduction (NHFR) values are produced either by the impingement/cross flow combination configuration or by the impingement only arrangement, depending upon the particular magnitude of BR, which is considered.

Effects of Double Wall Cooling Configuration and Conditions on Performance of Full Coverage Effusion Cooling

2016 ◽  
Author(s):  
Nathan Rogers ◽  
Zhong Ren ◽  
Warren Buzzard ◽  
Brian Sweeney ◽  
Nathan Tinker ◽  
...  
Keyword(s):  
Film Cooling ◽  
Cross Flow ◽  
Hole Array ◽  
Adiabatic Wall ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Full Coverage ◽  
Cooling Hole ◽  
Double Wall

Experimental results are presented for a double wall cooling arrangement which simulates a portion of a combustor liner of a gas turbine engine. The results are collected using a new experimental facility designed to test full coverage film cooling and impingement cooling effectiveness using either cross flow, impingement, or a combination of both to supply the film cooling flow. The present experiment primarily deals with cross flow supplied full coverage film cooling for a sparse film cooling hole array that has not been previously tested. Data are provided for turbulent film cooling, contraction ratio of 1, blowing ratios ranging from 2.7 to 7.5, coolant Reynolds numbers based on film cooling hole diameter of about 5,000–20,000, and mainstream temperature step during transient tests of 14 °C. The film cooling hole array consists of a film cooling hole diameter of 6.4 mm with non-dimensional streamwise (X/de) and spanwise (Y/de) film cooling hole spacing of 15 and 4, respectively. The film cooling holes are streamwise inclined at an angle of 25 degrees with respect to the test plate surface and have adjacent streamwise rows staggered with respect to each other. Data illustrating the effects of blowing ratio on adiabatic film cooling effectiveness and heat transfer coefficient are presented. For the arrangement and conditions considered, heat transfer coefficients generally increase with streamwise development, and increase with increasing blowing ratio. The adiabatic film cooling effectiveness is determined from measurements of adiabatic wall temperature, coolant stagnation temperature, and mainstream recovery temperature. The adiabatic wall temperature and adiabatic film cooling effectiveness generally decrease and increase, respectively, with streamwise position, and generally decrease and increase, respectively, as blowing ratio becomes larger.

Louver Slot Cooling and Full-Coverage Film Cooling With a Combination Internal Coolant Supply

2020 ◽  
Author(s):  
Austin Click ◽  
Phillip M. Ligrani ◽  
Maggie Hockensmith ◽  
Joseph Knox ◽  
Chandler Larson ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Film Cooling ◽  
Cross Flow ◽  
Test Surface ◽  
Test Plate ◽  
Blowing Ratio ◽  
Impingement Jet ◽  
Full Coverage ◽  
Film Cooling Holes

Abstract Within the present investigation, a louver slot is employed upstream of an array full coverage film cooling holes. Cooling air is supplied using a combination arrangement, with cross-flow and impingement together. The louver consists of a row of film cooling holes, contained within a specially-designed device which concentrates, and directs the coolant from a slot, so that it then advects as a layer downstream along the test surface. This louver-supplied coolant is then supplemented by coolant which emerges from different rows of downstream film cooling holes. The same coolant supply passage is employed for the louver row of holes, as well as for the film cooling holes, such that different louver and film cooling mass flow rates are set by different hole diameters for the two different types of cooling holes. The results are different from data provided by past investigations, because of the use and arrangement of the louver slot, and because of the unique coolant supply configurations. The experimental results are given for mainstream Reynolds numbers from 107000 to 114000. Full-coverage blowing ratios are constant with streamwise location along the test surface, and range from 3.68 to 5.70. Corresponding louver slot blowing ratios then range from 1.72 to 2.65. Provided are heat transfer coefficient and adiabatic effectiveness distributions, which are measured along the mainstream side of the test plate. Both types of data show less variation with streamwise development location, relative to results obtained without a louver employed, when examined at the same approximate effective blowing ratio, mainstream Reynolds number, cross flow Reynolds number, and impingement jet Reynolds number. When compared at the same effective blowing ratio or the same impingement jet Reynolds number, spanwise-averaged heat transfer coefficients are consistently lower, especially for the downstream regions of the test plate, when the louver is utilized. With the same type of comparisons, the presence of the louver slot results in significantly higher values of adiabatic film cooling effectiveness (spanwise-averaged), particularly at and near the upstream portions of the test plate. With such characteristics, dramatic increases in thermal protection are provided by the presence of the louver slot, the magnitudes of which vary with experimental condition and test surface location.

Louver Slot Cooling and Full-Coverage Film Cooling With a Combination Internal Coolant Supply

2021 ◽  
Vol 143 (3) ◽  
Author(s):  
Austin Click ◽  
Phillip M. Ligrani ◽  
Maggie Hockensmith ◽  
Joseph Knox ◽  
Chandler Larson ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Film Cooling ◽  
Cross Flow ◽  
Test Surface ◽  
Test Plate ◽  
Blowing Ratio ◽  
Impingement Jet ◽  
Full Coverage ◽  
Film Cooling Holes

Abstract Within the present investigation, a louver slot is employed upstream of an array full-coverage film cooling holes. Cooling air is supplied using a combination arrangement, with cross-flow and impingement together. The louver consists of a row of film cooling holes, contained within a specially designed device that concentrates and directs the coolant from a slot, so that it then advects as a layer downstream along the test surface. This louver-supplied coolant is then supplemented by coolant which emerges from different rows of downstream film cooling holes. The same coolant supply passage is employed for the louver row of holes, as well as for the film cooling holes, such that different louver and film cooling mass flowrates are set by different hole diameters for the two different types of cooling holes. The results are different from data provided by past investigations, because of the use and arrangement of the louver slot, and because of the unique coolant supply configurations. The experimental results are given for mainstream Reynolds numbers from 107,000 to 114,000. Full-coverage blowing ratios are constant with streamwise location along the test surface and range from 3.68 to 5.70. Corresponding louver slot blowing ratios then range from 1.72 to 2.65. Provided are heat transfer coefficient and adiabatic effectiveness distributions, which are measured along the mainstream side of the test plate. Both types of data show less variation with streamwise development location, relative to results obtained without a louver employed, when examined at the same approximate effective blowing ratio, mainstream Reynolds number, cross-flow Reynolds number, and impingement jet Reynolds number. When compared at the same effective blowing ratio or the same impingement jet Reynolds number, spanwise-averaged heat transfer coefficients are consistently lower, especially for the downstream regions of the test plate, when the louver is utilized. With the same type of comparisons, the presence of the louver slot results in significantly higher values of adiabatic film cooling effectiveness (spanwise-averaged), particularly at and near the upstream portions of the test plate. With such characteristics, dramatic increases in thermal protection are provided by the presence of the louver slot, the magnitudes of which vary with the experimental condition and test surface location.

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