Secondary flow and heat transfer coefficient distributions in the developing flow region of ribbed turbine blade cooling passages

Direct Simulation of Internal Flow Transient Liquid Crystal Experiments

“…This is seen to be up to 43% at t = 1.0 s relative to t = 15.0 s. By t = 5.0 s the maximum difference is seen to fall to 18%. In the region of the passage where the secondary flow vortices are seen to coalesce and impinge the trailing edge (250 < z < 310 mm, see Figure 7b and discussion in [8]), the variation of Nu with time is significantly lower, peaking at 12% difference, and quickly converging to < 5% difference. This is potentially due to the better mixing of the flow in this region.…”

“…Although improvements in IR camera technology has seen a reduction in TLC's application for external flow cases, the difficulties for imaging the internal surface has seen a continued application of the method. Narrow band liquid crystals have been shown to produce the most robust and accurate solutions, particularly if multiple crystals are applied to give information over a wide range of temperatures [8]. The technique is widely used for measuring heat transfer from gas turbine internal cooling component geometries.…”

Analysis of heat transfer on turbulence-generating ribs using dynamic mode decomposition

“…However it was shown by Wright et al [60] that by breaking up rib patterns, heat transfer can further improve. In addition to modifying the pattern of ribs, some researchers choose to modify ribs in a local (but still parametric) manner; ribs can appear with truncations as in Xie et al [61] and Forsyth et al [14], and with other geometric features like dimples as in Mhetras et al [30]. The rib geometry is also modified from a square cross-section to trapezoids in Ali et al [3], circles in Dritselis [12], and wedge features in Valentino et al [57].…”

“…14 shows the analysis for the 3rd row in table 3.5. All N appear with modes inside the circle, though generally increasing N helps convergence.…”

Heat Transfer Measurements Using Multiple Thermochromic Liquid Crystals in Symmetric Cooling Channels

“…Multiple TLCs can be applied in layers or within mixtures (e.g., Refs. [9][10][11][12][13][14][15][16]) also in combination with multiple fluid flow temperature changes. This has been used, e.g., for multiple parameter determinations such as heat transfer coefficient and adiabatic wall temperature in impingement cooling and film cooling situations [17,18].…”