... of CO 2 separation systems. This strategy can, however, reduce the oxygen concentration in the air, leading to changes in flame stabilization in the combustor. In this study, we investigate the effect of air diluted with inert gases of different compositions and the impact that these mixtures have...

...Xuren Zhu; Joel C. Lisanti; Thibault F. Guiberti; William L. Roberts Resonant pulse combustors, one of the deflagration-based pressure gain combustion devices, can significantly increase thermal efficiency in gas turbine engines. This experimental study investigates the stability characteristics...

...Leonardo Urbiola-Soto; Paolo Pennacchi This paper presents component and system-level analyses to understand the stiffness, damping, and rotor stability effects of tilting pad journal bearings (TPJB) with assembled clearance variation across pads. This variation results from a normal manufacturing...

... is built based on total potential energy. The dynamic model consists of a time-independent stiffness matrix for perfect bolts, a time-variant reductive stiffness, and an additional moment. As a result, the crack in bolt reduces rotor's nonlinear stability and leads to greater vibration and fluctuation...

... stability High speed turbochargers are intended to increase the power of internal combustion engines. For the commercial 3.9 liter diesel engine used for this research, the stock turbocharger increases the nonturbo engine power by 85%. The first turbocharger was invented in the early twentieth...

...Andrew P. Shroll; Santosh J. Shanbhogue; Ahmed F. Ghoniem This work explores the dynamic stability characteristics of premixed CH 4 /O 2 /CO 2 mixtures in a 50 kW swirl stabilized combustor. In all cases, the methane-oxygen mixture is stoichiometric, with different dilution levels of carbon dioxide...

... small electric machines softening thermal resistance viscosity air foil bearing thermo-hydrodynamic computational fluid dynamics dynamic performance stability Environment-friendly microturbomachinery (defined as less than 1 MW by the Gas Turbine Institute) has broad current...

...Naohiko Takahashi; Yohei Magara; Mitsuhiro Narita; Haruo Miura Since heavier gases exert larger effects on rotordynamic stability, stability evaluation is important in developing or designing high-pressure compressors. To evaluate the rotor stability during operation, an excitation test using...

...Yuan Liu; Manuj Dhingra; J. V. R. Prasad This paper presents a method for estimating compressor stall margin and the results of applying the estimation technique to an axial compressor rig. Stall margin estimation is accomplished through the use of a compressor stability detection parameter called...

... with the existing nonautonomous shooting method and is thus modified; the shooting method is used to obtain a steady state quasiperiodic solution. The eigenvalues of monodromy matrix provide information about stability and nature of bifurcation of the quasiperiodic solution. The maximum value of the Lyapunov...

... model has been developed. It leads to nonlinear differential equations of the second order, linearly coupled, in which the nonlinearity appears by cubic terms. Periodic solutions in both free and forced cases are sought by the HBM coupled with an arc length continuation and stability analysis...

...Mirko R. Bothien; Jonas P. Moeck; Christian Oliver Paschereit Linear stability analysis by means of low-order network models is widely spread in industry and academia to predict the thermoacoustic characteristics of combustion systems. Even though a vast amount of publications on this topic exist...

... water cooled reactors, as the density change is very large for the supercritical fluids. A computer code SUCLIN has been developed employing supercritical water properties to carry out the steady-state and linear stability analysis of a SCW natural circulation loop (SCWNCL). The conservation equations...

...Yuan Liu; Manuj Dhingra; J. V. R. Prasad An active engine control scheme for protection against compressor instabilities such as rotating stall and surge is presented. Compressor stability detection is accomplished via a parameter known as the correlation measure, which quantifies the repeatability...

...Yuan Liu; Manuj Dhingra; J. V. R. Prasad Active compressor stability management can play a significant role in the intelligent control of gas turbine engines. The present work utilizes a computer simulation to illustrate the potential operability benefits of compressor stability management when...

... simulations for stability analyses, and frequency-domain modal analyses for prediction of rotor-bearing natural frequencies. Scaling analysis indicates that direct miniaturization of macroscale tilting pad gas bearing can result in a large bearing number, which may render the rotor-bearing system unstable...

...Sébastien Le Lez; Mihaï Arghir; Jean Frêne One of the main interests of gas foil bearings lies in their superior rotordynamic characteristics compared with conventional bearings. A numerical investigation on the stability limit and on the unbalanced response of foil bearings is presented...

... with enhanced rotordynamic stability; and when modified for hydrostatic pressurization, demonstrate superior rotordynamic performance over other bearing types. External pressurization stiffens gas bearings thus increasing system critical speeds, albeit reducing system damping. Most importantly, measurements...

... hydrodynamics lubricating oils lubrication machine bearings reliability rotors wear airfoil bearing hydrostatic hybrid perturbation analysis stability Airfoil bearings have been successfully used in high speed microturbomachinery such as turbocharger∕generators, aircraft air cycle...

... to counteract compressor stability problems. Especially, using recirculating bleed air for increasing the surge margin of a compressor affects the performance of the engine negatively. Two examples show clearly that the pros and cons of recirculating bleed can only be judged with a full system simulation...