Nuclear Power Sources for Space Systems

Kukharkin, N. E.; Ponomarev-Stepnoi, N. N.; Usov, V. A.

doi:10.1007/978-1-4419-0720-2_59

Cited by 1 publication

(1 citation statement)

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“…With the increasing demand for propulsion power and higher cycle thermal efficiencies, higher turbine inlet temperatures and higher compressor pressure ratios are required for modern gas turbines [1]. In some industrial applications, the temperature of the exhaust gases from the combustion chamber can reach as high as 1000-1400 K [2,3] while in some advanced military engines, that temperature can reach 1800 K [4,5]. However, the materials of the hot section parts of the modern gas turbines cannot survive the extreme temperatures and loads.…”

Section: Introductionmentioning

confidence: 99%

Effects of Diffusion Film Hole Exit Area on the Film Cooling Effectiveness

Fan

Taslim

2022

International Journal of Rotating Machinery

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One popular method for the protection of gas turbines' hot sections from high-temperature combustor gases is film cooling. Substantial amounts of research have been conducted to accomplish this task with the minimum cooling flow, maximum surface coverage, and minimal aerodynamic inefficiencies or structural penalties. In this study, a combined experimental and numerical investigation was conducted on three selected film-cooling hole geometries. These geometries were designed with the same initial metering (feed) section, a cylindrical hole of 30 °inclination angle, followed by three different forward expansion section geometries. The expansion sections had a 7 °laid-back angle and a 17 °expansion angle in each lateral direction. However, different interior corner radii were used to blend the metering hole to the exit area, creating three different expansion geometries with almost the same exit areas. In practice, this variation in expansion geometry could represent manufacturing faults or tolerances in laser drilling of the film holes. This study shows that the variations in film-cooling effectiveness are not significant even though the expansion geometries are significantly different. The Pressure Sensitive Paint (PSP) technique was used to obtain the detailed distribution of film-cooling effectiveness on the surface area downstream of these film holes. Adiabatic film cooling effectiveness was measured at blowing ratios of 0.5, 1.0, and 2.0. CFD models of these film holes were also run, and the results were compared with the test data. The major conclusions of this study were that these proposed new geometries produced higher film effectiveness than the conventional 7 °-7 °-7 °diffusion film holes, for the same exit area, the expansion section geometry of the film holes did not have a significant effect on the film coverage, and the numerical results were in good agreement with the test data.

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