...P. Marugabandhu; J. H. Griffin A reduced-order model has been developed that can be used to accurately and quickly calculate the changes in the natural frequencies and mode shapes of a blade that are caused by centrifugal stiffening. It has been corroborated by comparisons with finite element...

... of uncertainty and when modeling assumptions weaken. Here FAN, LPC, HPC, HPT, and LPT are fuzzy sets denoting the five engine modules. Each fuzzy set has degrees of membership ranging from zero to one. In this paper, we are only interested in the module containing the fault. Therefore, we do not further...

...I. F. Santos; A. Scalabrin This work focuses on the theoretical and experimental behavior of rigid rotors controlled by tilting-pad journal bearings with active oil injection. Initially the mathematical model of the active bearing is presented: The equations that describe the dynamics of hydraulic...

... and particulate emissions with retarded injection timing. According to the results of CFD computation and phenomenological modeling, the high squish combustion chamber with a central pip is effective to keep the combusting mixture under the squish lip until the end of combustion and the combustion region forms...

... horizontally with piano wire. These frequency response functions are compared with the responses of a rotor model and a reconciliation process is used to reduce the discrepancies between the model and the measured data. In this identification, the wire and the fit of the magnetic bearing journals...

... of such a structure with a single harmonic mistuning pattern are shown to obey the Mathieu equation, which is solved to obtain the natural frequencies and modes of the mistuned system. The forced response of the system is then examined to determine the sensitivity of the system to small mistuning. The model...

... magnets (PM’s). The main advantage of the design is that it eliminates the tradeoff between motoring torque and bearing force with PM thickness as found in previous designs. This paper presents the dynamic model for the self-bearing motor and illustrates how the model is integrated into the overall system...

... have a large/small sensitivity to random unintentional mistuning. In this manner, expensive Monte Carlo simulations can be eliminated. Examples of application involving both simple bladed disk models and a 17-blade industrial rotor clearly demonstrate the significant benefits of using this class...

...N. Chiras; C. Evans; D. Rees This paper examines the estimation of a global nonlinear gas turbine model using NARMAX techniques. Linear models estimated on small-signal data are first examined and the need for a global nonlinear model is established. A nonparametric analysis of the engine...

... clearance, a simplified earlier analysis showed that rotor bearing systems (RBSs) with deep groove ball bearings can give rise to chaotic motion and jump. This paper extends the bearing model to include rolling element centrifugal load, angular contacts and axial dynamics; and illustrates their effects...

...T. Yang; C. Lin Mass unbalance commonly causes vibration of rotor-bearing systems. Lumped mass modeling of unbalance was adapted in most previous research. The lumped unbalance assumption is adequate for thin disks or impellers, but not for thick disks or shafts. Lee et al. (Lee, A. C., et al...

..., Dec. 2000, final revision, Mar. 2001. Associate Editor: R. Natole. 04 June 2001 01 Dec 2000 01 Mar 2001 24 09 2002 gas turbines combustion bioenergy conversion thermal properties heat transfer coal gasification fuel modelling Gas turbine systems...

... the Grayson model, comprising the Redlich-Kwong equation of state for vapor state ( 15 ) and the Lee-Kesler equation of state for liquid and vapor enthalpy. Steam parameters have been calculated through NBS/NBC steam tables ( 16 ). All the calculations were performed with Aspen + software ( 17...

... to the contact surface (due to interference between adjacent segments) on friction damping is shown. Moreover, the experiments show the nature of friction at contact surfaces. The parameters of a contact model to be used in a numerical analysis have been identified from the experiments. Menq , C. H...

... are more demanding than for a conventional regeneration configuration, but well within the capability of modern heat exchangers. Models of cycle performance exhibit several percentage points of improvement relative to either simple cycles or conventional regeneration schemes. The peak efficiencies...

...; final revision received by ASME Headquarters, Februry 2000. Associate Editor: D. Wisler. 08 May 2000 01 November 1999 19 06 2002 cogeneration power stations gas turbines thermodynamics modelling power generation economics Disposing of a hot gas at ambient pressure...

... testing of an industrial gas turbine are used to check the validity of the proposed relations. The comparison of the predictions to the test data shows that the mechanisms of performance deviations are well modeled by the analysis presented. Shaw , H. , 1974 , “ The Effects of Water, Pressure...

... the frequency response function (FRF) matrix of the tuned system and a matrix describing the mistuning. The main advantages of the method are its efficiency and accuracy, which allow the use of large finite element models of practical bladed disk assemblies in parametric studies of mistuning effects...

... distribution but avoiding their disadvantages. In order to identify requirements on the time-frequency analysis and also correlate a time-frequency analysis result with noise sources, the composition of the noise signal is discussed first. With this discussion, a mathematical model has been suggested...

... two-phase flows. The Eulerian and Lagrangian methods are two essentially different approaches for the modeling of disperse two-phase flows. Both methods have been implemented into the same computational fluid dynamics package which is based on a three-dimensional body-fitted finite volume method...