TY - GEN
T1 - Unsteady heat flux measurements of junction flow with reynolds number and freestream turbulence effects
AU - Elahi, Syed S.
AU - Moul, Zachary K.
AU - Lange, Eric A.
AU - Lynch, Stephen P.
N1 - Funding Information:
This work was sponsored by the Office of Naval Research, ONR, under grant number N00014-15-1-2764; the views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the Office of Naval Research, the U.S. Navy or the U.S. government.
Publisher Copyright:
© 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
PY - 2018
Y1 - 2018
N2 - Turbulent junction flow is a three-dimensional unsteady phenomenon occurring in the flow upstream of the leading edge of bodies attached to a surface, such as in turbine rotors and stators, heat exchangers, submarine appendages, and wing-fuselage attachments. One of the signature features of this type of flow is the presence of bimodal behavior in the probability density functions of velocity, but the bimodal phenomenon has not been observed in surface heat flux measurements. However, it is well-known that time-mean levels of heat flux are significant. In situations where the body experiences high freestream turbulence, mean heat flux is further increased, but the mechanisms of the enhancement are unclear. In this paper, a test section for simultaneous time-resolved heat flux and flowfield measurements in front of a common research wing is highlighted. Time-resolved unsteady heat flux is also reported for a range of Reynolds numbers at high freestream turbulence. Time-resolved heat flux measurements from the symmetry plane of the junction region are compared with measurements downstream of the airfoil to determine if there are correlated behaviors. Also, a comparison between the effects of baseline freestream turbulence and high freestream turbulence on junction heat transfer is presented. It is found that at the plane of symmetry, high freestream turbulence increases endwall heat transfer at low Reynolds number and has negligible influence on endwall heat transfer at high Reynolds number.
AB - Turbulent junction flow is a three-dimensional unsteady phenomenon occurring in the flow upstream of the leading edge of bodies attached to a surface, such as in turbine rotors and stators, heat exchangers, submarine appendages, and wing-fuselage attachments. One of the signature features of this type of flow is the presence of bimodal behavior in the probability density functions of velocity, but the bimodal phenomenon has not been observed in surface heat flux measurements. However, it is well-known that time-mean levels of heat flux are significant. In situations where the body experiences high freestream turbulence, mean heat flux is further increased, but the mechanisms of the enhancement are unclear. In this paper, a test section for simultaneous time-resolved heat flux and flowfield measurements in front of a common research wing is highlighted. Time-resolved unsteady heat flux is also reported for a range of Reynolds numbers at high freestream turbulence. Time-resolved heat flux measurements from the symmetry plane of the junction region are compared with measurements downstream of the airfoil to determine if there are correlated behaviors. Also, a comparison between the effects of baseline freestream turbulence and high freestream turbulence on junction heat transfer is presented. It is found that at the plane of symmetry, high freestream turbulence increases endwall heat transfer at low Reynolds number and has negligible influence on endwall heat transfer at high Reynolds number.
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U2 - 10.2514/6.2018-0358
DO - 10.2514/6.2018-0358
M3 - Conference contribution
AN - SCOPUS:85141586165
SN - 9781624105241
T3 - AIAA Aerospace Sciences Meeting, 2018
BT - AIAA Aerospace Sciences Meeting
PB - American Institute of Aeronautics and Astronautics Inc, AIAA
T2 - AIAA Aerospace Sciences Meeting, 2018
Y2 - 8 January 2018 through 12 January 2018
ER -