Wall thickness and injection direction effects on flat plate full-coverage film cooling arrays: Adiabatic film effectiveness and heat transfer coefficient

2D and 3D thermoelastic phenomena in double wall transpiration cooling systems for gas turbine blades and hypersonic flight

“…Evidently, for both cases A-B, Figs 14c-d indicate that both compressive and tensile stresses in the outer and inner wall 1 surfaces, increase away from the pedestals, especially at the effusion hole location, 𝜃 ̅ = 𝑧̅ = 0. The major role of inner wall thickness and wall spacing, 𝑡 ̂2 − 𝐻 ̂, is expected to be similar to the case when a hot temperature is applied on the convex surface (Fig 16).…”

“…Currently, effusion and transpiration are cutting edge external cooling strategies that already allow operating temperatures beyond the material limits of engine core components [4,8,14]. This is primarily due to the large decrease in the temperature driving heat transfer from the mainstream hot gas flow onto the metal, which is achieved by ejecting internal coolant through effusion/film holes at the exterior surface of the component, in a directed manner, such that a protective cool film is formed [5,15,16]. Double wall transpiration cooling (DWTC) is a more advanced concept which enables the combination of the above external cooling technique with internal cooling features, consisting of coolant impingement and pedestals; the role of these internal features can be demonstrated through the double wall system presented by Murray et al [17] for an aerofoil, shown here in Fig 1a . Specifically, pedestals connect the two walls and simultaneously offer conductive cooling of the hot outer skin, while impingement holes eject high speed coolant jets onto the inner surface of the outer wall, thus promoting convective cooling.…”

Performance improvement of high-speed EDM and ECM combined process by using a helical tube electrode with matched internal and external flushing

“…In the context of aviation manufacturing, a large number of microscopic cooling holes are present in films on the surfaces of the turbine blades of aero-engines [1][2][3], and these micro-holes are distributed on the blades at different angles [4][5][6]. Such a structure can be used to form a film of cooling gas on the surface of the blade to ensure its reliable operation in the ultra-high-temperature environment of the combustion chamber [7][8][9].…”