Statistical analysis of three-dimensional run-up heights using Gaussian process emulator of particle method

In the array design of the vertical axis wind turbines (VAWT), the wake effect of the upstream VAWT on the downstream VAWT needs to be considered. In order to simulate the velocity distribution of a VAWT wake rapidly, a new two-dimensional numerical method is proposed, which can make the array design easier and faster. In this new approach, the finite vortex method and vortex particle method are combined to simulate the generation and evolution of the vortex, respectively, the fast multipole method (FMM) is used to accelerate the calculation. Based on a characteristic of the VAWT wake, that is, the velocity distribution can be fitted into a power-law function, a new correction model is introduced to correct the three-dimensional effect of the VAWT wake. Finally, the simulation results can be approximated to the published experimental results in the first-order. As a new numerical method to simulate the complex VAWT wake, this paper proves the feasibility of the method and makes a preliminary validation. This method is not used to simulate the complex three-dimensional turbulent evolution but to simulate the velocity distribution quickly and relatively accurately, which meets the requirement for rapid simulation in the preliminary array design.

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Numerical simulation for diffusion of matter in compound round jet by three-dimensional particle method

Chemical Engineering Science ◽

10.1016/j.ces.2004.07.119 ◽

2005 ◽

Vol 60 (2) ◽

pp. 337-345 ◽

Cited By ~ 2

Author(s):

Tomomi Uchiyama ◽

Akihito Ichikawa

Keyword(s):

Numerical Simulation ◽

Three Dimensional ◽

Particle Method ◽

Round Jet

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Run-Up Simulation of a Semi-Floating Ring Supported Turbocharger Rotor Considering Thrust Bearing and Mass-Conserving Cavitation

Lubricants ◽

10.3390/lubricants9040044 ◽

2021 ◽

Vol 9 (4) ◽

pp. 44

Author(s):

Christian Ziese ◽

Cornelius Irmscher ◽

Steffen Nitzschke ◽

Christian Daniel ◽

Elmar Woschke

Keyword(s):

Reynolds Equation ◽

Energy Equation ◽

Thrust Bearing ◽

Three Dimensional ◽

Reliable Prediction ◽

Two Phase ◽

Hydrodynamic Bearings ◽

Thrust Bearings ◽

Run Up ◽

The Impact

The vibration behaviour of turbocharger rotors is influenced by the acting loads as well as by the type and arrangement of the hydrodynamic bearings and their operating condition. Due to the highly non-linear bearing behaviour, lubricant film-induced excitations can occur, which lead to sub-synchronous rotor vibrations. A significant impact on the oscillation behaviour is attributed to the pressure distribution in the hydrodynamic bearings, which is influenced by the thermo-hydrodynamic conditions and the occurrence of outgassing processes. This contribution investigates the vibration behaviour of a floating ring supported turbocharger rotor. For detailed modelling of the bearings, the Reynolds equation with mass-conserving cavitation, the three-dimensional energy equation and the heat conduction equation are solved. To examine the impact of outgassing processes and thrust bearing on the occurrence of sub-synchronous rotor vibrations separately, a variation of the bearing model is made. This includes run-up simulations considering or neglecting thrust bearings and two-phase flow in the lubrication gap. It is shown that, for a reliable prediction of sub-synchronous vibrations, both the modelling of outgassing processes in hydrodynamic bearings and the consideration of thrust bearing are necessary.

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