Скачать или смотреть Hot Spot Stability Analysis with the Rotor Dynamics Software MADYN 2000

In the video the hot spot stability analysis ("Morton effect") of an overhung rotor with the software MADYN 2000 is shown.



Heating can be proportional to the displacement, the velocity or the acceleration of the shaft.
For bearing hot spots – also known as Morton effect – the heat input and heat dissipation coefficients can be automatically calculated from the bearing data.
User-defined heating models with speed-dependent coefficients for heat input and heat dissipation are possible, e.g. for brush seals.
A phase angle between high spot and hot spot can be specified.
Multiple hot spots are analysed simultaneously!


MADYN 2000 is a leading rotordynamics software developed by DELTA JS.
One of its unique features is the hot spot stability analysis, which allows assessing the risk of thermally induced rotor instabilities.
In this video we analyse a double overhung rotor for hot spots in the fluid film bearings, also known as Morton effect.
Both the Campbell diagram of the damped eigenvalues and the resonance curves of the unbalance response analysis proved that the rotor has its lowest critical speed significantly above the operating speed range, which is marked with a blue area.
The hot spots are applied at the two shaft stations with the fluid film bearings. For a hot spot due to the Morton effect the length, the heating type and the coefficients for heat input and heat dissipation can be calculated from the bearing parameters by the program.
In the shaft model plot the hot spot locations are marked with red flash symbols.
As the first step of the analysis procedure the thermal shaft bending due to a unit temperature difference across the shaft diameter at the hot spot location is calculated for the free shaft. As an example the deformation plot for heating at the left bearing is shown.
In the hot spot stability analysis the eigenvalues of a system that is extended by the thermal equations for the hot spots are calculated as a function of the speed - similar to a Campbell diagram. The influence of all hot spots is considered simultaneously. The number of hot spot modes is equal to the number of specified hot spots. The use of a fine speed step in the analysis ensures smooth curves in the result plots.
Various hot spot result plots are available.
In the stability threshold plot the green and red stability thresholds of the two hot spot modes are shown. Instability occurs if the actual heat ratio curve in black is above the lowest threshold curve.
In the stability threshold factor plot the factor is shown by which the actual heat ratio must be multiplied to reach the lowest stability threshold. If the factor is less than one instability occurs.
The shapes of the two hot spot modes can be plotted. The rotation frequency of the hot spot on the shaft surface as well as its direction are also available in the results.
The hot spot stability analysis in MADYN 2000 offers full flexibility to model virtually any hot spot mechanism.
Are you interested in our advanced rotordynamics software? Feel free to contact us for more information.