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This paper investigates effects of geometrical and coolant flow parameters for a three-row compound angle hole design over a flat plate. These included β = +45° and −45°, in-line and staggered arrangement, hole spacing (4d, 6d and 8d), five blowing ratios (0.5–1.5) and three density ratios (1.0, 1.5, 2.0). Spanwise averaged effectiveness plots and contours were developed using Pressure-Sensitive Paint (PSP) technique and cross comparisons were carried out. The parametric results obtained from experiment generally agreed with widely accepted trends: the cascade effect of coolant jets for multi-hole design increases film effectiveness especially at large x/d, increasing density ratio increases effectiveness particularly at higher blowing ratio and increasing hole spacing has a detrimental effect on film cooling. However, some interesting observations are discovered including: staggered arrangement is not always the most optimum design (β = +45°, −45°, −45° with staggered 2nd and 3rd row reported the lowest effectiveness for all blowing ratios and density ratios); in-line arrangement of holes with opposing orientation angles (β = +45°, −45°, −45°) yields better effectiveness; blowing ratio effect is strongly dependent on geometric design. Moreover, hole spacing effect is closely related to neighboring coolant jet coalescence and interaction with mainstream flow. Currently, little data is available on three-row design in open literature; this study provides systematic, baseline information for future studies.

The laminated cooling configuration with integrated impingement, rib-roughed and film cooling can result in high overall cooling effectiveness and is believed to be a promising cooling configuration for the next generation of advanced gas turbines. Typical laminated cooling configuration usually employs discrete film holes which have the similar hole topology along the streamwise and the spanwise direction. Because the functioning distance of film cooling along the streamwise direction is much longer than that along the spanwise direction. So the discrete film cooling cannot perform well in the spanwise direction. A novel laminated cooling layout in which the film outlet spacing in the spanwise direction is much shorter than that in the typical layout was presented in this paper. The angled film holes are also employed to enhance the film cooling effectiveness and to reduce the coolant flow resistance. Conjugate heat transfer computations were performed to assess the overall cooling effectiveness and the coolants resistance. The computational results show that by employing angled film hole on laminated configurations with novel layout, the area-averaged overall cooling effectiveness was considerably improved.

This work experimentally investigates the heat transfer characteristics of Taylor–Couette–Poiseuille flow in an annular channel by mounting longitudinal ribs on the rotating inner cylinder. The ranges of the axial Reynolds number (Re) and the rotational Reynolds number (ReΩ) are Re = 30–1200 and ReΩ = 0–2922, respectively. Three modes of the inner cylinder without/with longitudinal ribs are considered. A special entry and exit design for the axial coolant flow reveals some interesting findings. The value of Nusselt number (Nu) is almost minimal at the inlet of the annular channel, and then sharply rises in the axial direction. The average Nusselt number ( Nu ¯ ) increases with Re. Nu increases rapidly with ReΩ at low Re (such as at Re = 30 and 60) but that the effect of ReΩ decreases as the value increases (such as at Re = 300–1200). The ratio Nu ¯ / Nu ¯ 0 increases with ReΩ and exceed two at all Re and in the test modes. The heat transfer is typically promoted by mounting longitudinal ribs on the rotating inner cylinder, especially at Re = 300 and 600. When Re = 300 or 600 and ReΩ > 2000, the Nu ¯ of the system with ribs reaches around 1.4 times that of Nu ¯ A ( Nu ¯ in mode A). Under a given pumping power constraint (PRe3), the Nu ¯ of the system with ribs (modes B and C) generally exceeds that without ribs (mode A), while the difference between the values of Nu ¯ in modes B and A slowly falls as PRe3 increases. Additionally, mode B (with ribs) is preferred for high heat transfer when PRe3 4.5 × 1013.

Heat transfer phenomena in two types of eutectic crystallizers have been analyzed. This equipment is equipped with rotating scraper blades and the effect of the blade action on heat transfer phenomena in both crystallizing and non-crystallizing conditions is studied. It was found that the coolant flow in the equipment can be described by fitted Dittus–Boelter relations. In both crystallizers the transport of heat from process liquid to cooled wall surfaces at various rotational speeds of the scrapers can generally be accurately described with penetration theory. Exceptions are approximated with fitted Re – Pr -relations. Both increasing and decreasing heat transfer rates have been found in crystallizing conditions at increasing scraping rates. Differences are attributed to geometrical crystallizer characteristics and solid content.