Article
Heat and Mass Transfer and Physical Gasdynamics
2022. V. 60. № 2. P. 208–214
Isaev S.A., Nikushchenko D.V., Popov I.A., Sudakov A.G., Tryaskin N.V., Iunakov L.P.
Heat transfer enhancement in a dimpled narrow channel during the transformation of separated turbulent flow with increasing slope angle of a solitary conical dimple
Annotation
A numerical study of turbulent Re=40000) flow around a solitary conical dimple with a depth of 0.233 of the spot diameter on the wall of a narrow channel (with a cross section of 2.5×0.33) is carried out with change in slope angle θ. The transformation of the jet-vortex structure of the mean flow from a symmetric system of paired vortices to a monotornado flow leads to an intensification of the separated flow and heat transfer enhancement. The maximum velocities of the return and secondary flows increase by 25 and 40%, respectively, while the maximum turbulent energy drops abruptly by 30%. The minimum relative negative friction at the bottom of the dimple decreases by a factor of 2.5 (reaching –1.5). After \theta = 45^{\circ}, there is a fairly rapid decrease in the intensity of the separated flow in the dimple. The thermal efficiency of the control section with a dimple noticeably lags behind the growth of relative hydraulic losses; however, thermal-hydraulic efficiency THE = (\mathrm{Nu}_{mm}/\mathrm{Nu}_{mm\mathrm{pl}})/(\xi/\xi_{\mathrm{pl}})^{1/3} is close to unity.
Article reference:
Isaev S.A., Nikushchenko D.V., Popov I.A., Sudakov A.G., Tryaskin N.V., Iunakov L.P. Heat transfer enhancement in a dimpled narrow channel during the transformation of separated turbulent flow with increasing slope angle of a solitary conical dimple, High Temp., 2022. V. 60. № 2. P. 208
Isaev S.A., Nikushchenko D.V., Popov I.A., Sudakov A.G., Tryaskin N.V., Iunakov L.P. Heat transfer enhancement in a dimpled narrow channel during the transformation of separated turbulent flow with increasing slope angle of a solitary conical dimple, High Temp., 2022. V. 60. № 2. P. 208