Lucena-Jiménez, John A.

Profile Picture

Filters

20111
Reset filters

Settings

Citations

Publication Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    Publication
    DNS of turbulent channel flow with inclined, continuous and segmented V-shaped turbulators
    (2011-05) Lucena-Jiménez, John A.; Leonardi, Stefano; College of Engineering; Pandya, R. Vikram; Cancelos, Silvina; Department of Mechanical Engineering; Castillo, Paul
    The cooling system of the gas turbine blades plays a critical role in increasing the thermal efficiency and power output of advanced gas turbine engines. In fact, by increasing the heat transfer, the turbine blade can resist to an impinging fluid with higher temperature. Roughness elements (turbulators) are usually placed on the walls of the internal channels of a turbine blade to enhance the heat transfer. Direct numerical simulations are carried out to study the turbulent flow in a square channel with continuous V- shaped turbulators on one wall and segmented V-shaped square ribs on two walls. The geometrical parameters are k/h = 0.25, w/k = 3, 5,α = 45, 60, 75 and G/H = 0.2, where k is the rib height, w the pitch, h the channel half height, α the angle in degrees with respect to the flow direction and G the gap size (segmented V-shape only). Numerical results show that the heat transfer is 9% higher while the drag is 10% lower for the segmented V-shaped configuration (w/k = 3,α = 45), when compared with that for continuous V-shaped turbulators. The drag reduction is due to the fact that turbulators have less surface perpendicular to the flow direction, and as a consequence, the form drag decreases. The heat transfer enhancement is caused by a change in the flow structure inside the cavity due to the stream through the gap. When the turbulators are placed on one wall only, the drag and heat transfer are, respectively, 3.00 and 3.04 less than that in continuous V-shaped turbulators. By varying the angle of the turbulators with respect to the flow direction, higher heat transfer and drag is found for α = 60 (w/k = 5).