...Thomas O. Jelly; Wagih Abu Rowin; Nicholas Hutchins; Daniel Chung; Koichi Tanimoto; Takuo Oda; Richard D. Sandberg Direct numerical simulations of incompressible turbulent forced convection over irregular, anisotropic surface roughness in a pressure-driven plane channel flow have been performed...

... the oil film thickness distribution and interface velocity at different engine operating conditions. Currently, Reynolds-averaged Navier–Stokes (RANS) CFD uses a semi-empirical method of turbulence damping, which is inaccurate for wavy films and so impacts the modeling of bearing chambers and gearboxes...

...Huang Chen; Yuanchao Li; Subhra Shankha Koley; Joseph Katz Challenges in turbulence modeling in the tip region of turbomachines include anisotropy, inhomogeneity, and non-equilibrium conditions, resulting in poor correlations between Reynolds stresses and the corresponding mean strain-rate...

... study focuses on the effect of resolution on flow physics and loss generation and uses a compressor cascade subjected to freestream turbulence. The results show that both resolving local entropy generation rate and capturing the inception and growth of instabilities are critical to accuracy of loss...

... a single blade passage back into the inlet of the computational domain. As a result, a type of repeating-passage simulation is obtained such as observed by an embedded blade-row. We find that freestream turbulence levels rise significantly as the size of the rotor-stator axial gap is reduced...

... turbulence Highly swirling flows are now widely employed in gas turbine combustors in order to improve the combustion aerodynamics. Swirl enhances the fuel-air mixing and thus reduces peak temperatures, which reduces NO x emissions. In addition, the recirculation zone that develops as a result...

...Vladimir Vassiliev; Stefan Irmisch; Samer Abdel-Wahab; Andrey Granovskiy The flow in exhaust diffusers along with the channel geometry strongly depends on the inflow conditions, including Mach number level, total pressure distribution, flow angle, and turbulence. In the first part of this paper...

... on the physics of flow and heat transfer in the rotor tip, casing, and hub regions. The simulation was performed using the unsteady Reynolds-averaged Navier–Stokes code MSU-TURBO . A low Reynolds number k- ε model was utilized to model turbulence. The rotor blade in question has a tip gap height of 2.1...

... 2011 21 07 2011 blades cooling flow visualisation mass transfer rotors stators turbulence vortices The efficiency of a gas turbine increases with the temperature of the hot combustion gases at the stage inlet. Modern gas turbines are designed to operate at turbine inlet...

... out at low speed ( M 2 is = 0.2 ) and low inlet turbulence intensity level, with coolant mass flow rate ratio varied within the 0.5–2.5% range. Pressure probe traverses were performed downstream of the vane trailing edge to show the secondary flow field modifications and to evaluate trench additional...

... of deterministic roughness is investigated in these experiments, varying the height and eccentricity of the roughness elements, showing the combined influence of roughness height and anisotropy of the rough surfaces on laminar to turbulent transition and the turbulent boundary layer as well as boundary layer...

... 03 08 2010 19 07 2011 19 07 2011 aerodynamics blades cooling Mach number turbines turbulence The aerothermal design of advanced high and low pressure turbine blades has progressed significantly in the past decade primarily due to the requirement of increased turbine...

.../1.1791287 Andrews , G. , Hussain , R. A. , and Mkpadi , M. , 2003 , “ Enhanced Impingement Heat Transfer: Comparison of Co-Flow and Cross-Flow With Rib Turbulators ,” Proceedings of the International Gas Turbine Congress , Paper No. IGTC2003Tokyo TS-075. Annerfeldt , M...

...Diganta P. Narzary; Kuo-Chun Liu; Akhilesh P. Rallabandi; Je-Chin Han Adiabatic film-cooling effectiveness is examined on a high-pressure turbine blade by varying three critical engine parameters, viz., coolant blowing ratio, coolant-to-mainstream density ratio, and freestream turbulence intensity...

... RANS applying a k - ε - v 2 - f turbulence model and the Spalart and Allmaras turbulence model and detached-eddy simulation (DES) based on the Spalart and Allmaras turbulence model are addressed to solve thermal convection. The CFD calculations were conducted by simulating a semicircular model...

... levels of turbulence, which are typically found in sharp turns, in ribbed ducts, and, especially, in rotating ducts. In the past, a slip between motor and channel rotation causes additional non-negligible uncertainties during PIV measurements due to an unstable image position. These were caused...

... profile has a strong effect on the position of flow separation, whereby a hub-strong profile tends to separate at the casing and the tip-strong profile on the hub. Steady computational fluid dynamics (CFD) simulations using the shear stress transport (SST) turbulence model have been carried out based...

...E. L. Erickson; F. E. Ames; J. P. Bons Heat transfer distributions are experimentally acquired and reported for a vane with both a smooth and a realistically rough surface. Surface heat transfer is investigated over a range of turbulence levels (low (0.7%), grid (8.5%), aerocombustor (13.5...

... of the effect of the coupled vortices. The waist-shaped slot holes provide the surface with very good thermal protection, especially in the upstream region. Although the console holes with small a exit-entry area ratio provide better thermal protection than the waist-shaped slot holes due to small turbulence...

...Ralph J. Volino Boundary layer separation has been studied on a very high lift, low pressure turbine airfoil in the presence of unsteady wakes. Experiments were done under low (0.6%) and high (4%) freestream turbulence conditions on a linear cascade in a low speed wind tunnel. Wakes were produced...