... slightly different from each other. As blisks lack the uncertainty and variability of friction properties related to joints, the maximum vibration response level of a blisk test piece in operation can be predicted prior to installation. A previously proposed response-level prediction procedure for mistuned...

... the effect of manufacturing roughness levels on these small channels. Convective heat transfer coefficients and friction factors were deduced based on measured flow conditions and known boundary conditions. It was shown that at an average roughness height of 6.1 μ m , which corresponded to 2.2...

...Akhilesh P. Rallabandi; Nawaf Alkhamis; Je-Chin Han Experiments to determine heat transfer coefficients and friction factors are conducted on a stationary 45 deg parallel rib-roughened square channel, which simulates a turbine blade internal coolant passage. Copper plates fitted with silicone...

... after the shaft breakage. The corresponding time-dependent high pressure turbine inlet conditions are used to calculate the turbine maximum speed, taking into account friction and blade and vane tip clearance variations as a result of the rearward movement of the turbine and destruction of the turbine...

... by a One-Dimensional Model,” ISROMAC Paper No. 12-2008-20161 ). In the present paper, the authors developed, using CFD tools, reliable correlations for both stator and rotor friction coefficients and provided a full 1D-code validation, due to the lack of experimental data, comparing the in-house design...

... on friction and heat transfer correlations for smooth and rib-roughened cooling channels. Special attention is given to the boundary conditions linking these solvers and to the stability of the complete CHT calculation procedure. The Larson–Miller parameter model is used to determine the creep-to-rupture...

...Giovanni Tanda; Roberto Abram, Ph.D. student Local and average Nusselt numbers and friction factors are presented for rectangular channels with an aspect ratio of 5 and angled rib turbulators inclined at 45 deg with parallel orientations on one and two surfaces of the channel. The convective fluid...

... acceleration between protrusions, while the turbulence generated in the wake has a secondary effect. Heat transfer augmentation ratios of 0.99 at Re H = 220 , 2.9 at Re H = 940 , and 2.5 at Re H = 9300 are obtained. Both skin friction and form losses contribute to pressure drop in the channel. Form losses...

...Jason E. Dees; David G. Bogard Skin friction coefficients and heat transfer coefficients are measured for a range of regular and random roughnesses on the suction side of a simulated gas turbine vane. The skin friction coefficients are calculated using boundary layer data and the momentum integral...

...Soo Whan Ahn; Ho Keun Kang; Sung Taek Bae; Dae Hee Lee An experimental study was carried out to investigate the heat transfer and friction characteristics of a fully developed turbulent air flow in a square channel with 45 deg inclined ribs on one, two, or four walls. Either two opposite walls...

...J. P. Bons; S. T. McClain; Z. J. Wang; X. Chi; T. I. Shih Skin friction ( c f ) and heat transfer (St) predictions were made for a turbulent boundary layer over randomly rough surfaces at Reynolds number of 1 × 10 6 . The rough surfaces are scaled models of actual gas turbine blade surfaces...

...J. R. Beisheim; G. B. Sinclair The stress analysis of dovetail attachments presents some challenges. These stem from the high stress gradients present, the contact inequalities attending conforming contact, and the nonlinearities inherent in Coulomb friction laws. Obtaining converged contact...

...Brian M. Holley; Lee S. Langston The flow near the leading edge stagnation line of a plane turbine cascade airfoil is analyzed using measurements, analytical modeling, and computational fluid dynamics modeling. New measurements of skin friction and pressure are used to show that the aerodynamics...

...J. Szwedowicz; R. Visser; W. Sextro; P. A. Masserey Numerical predictions of the forced vibration of a disk assembly including frictional effects between the shrouds are presented concerning engineering needs for the blade design process. Assuming a tuned disk assembly, numerical static, free...

... to be as great as 50 and this leads to laminar boundary layer shape factors as low as 1.3 and skin friction coefficients up to 12 times the value for a flat plate laminar boundary layer. Boundary layers therefore grow much more rapidly on concave surfaces than on flat plates. The transition model assumed...

... as function of such contact interface parameters as gap and interference values, friction and contact stiffness coefficients, and normal stresses. High accuracy and efficiency of the new method have been demonstrated on numerical examples including a large-scale nonlinear bladed disk model and major types...

... of the new models and an analysis of the influence of the damper parameters on the forced response of bladed disks is made. 01 10 2005 01 02 2006 blades discs (structures) friction vibration control mechanical contact finite element analysis Due to the high density of natural...

...E. P. Petrov; D. J. Ewins An approach is developed to analyze the multiharmonic forced response of large-scale finite element models of bladed disks taking account of the nonlinear forces acting at the contact interfaces of blade roots. Area contact interaction is modeled by area friction contact...

... confirmed that is believed to be responsible for the smaller spreading angle of spots measured at the wall. This finding is expected to have important implications to the development of improved transition models that are used to predict heat transfer and skin friction for turbine blades. laminar flow...

... flow are still not fully understood or quantitatively predictable. To better quantify wall friction contributions to endwall aerodynamic loss, low Mach number wind tunnel measurement of skin friction coefficients have been made on one endwall of a large scale cascade of high pressure turbine airfoils...