Bearing Design and Rotor Dynamics Software

The software is based on decades of experience in bearing development and rotor dynamics. The code has been developed since 1976. The recent developments include improvements and validations of program functions supported by the TECS program (Technical Enhancements and Customer Support) taking into account the actual customer and market needs. The implementation of thrust bearings and sealing systems is continuously improved and further developed together with radial tilting pad bearings.

The main benefit of the DYNROT program is a quick and highly simplified interaction between the bearing design and rotor dynamics. The user can provide quick and effective design changes and evaluate theirs impact within a few seconds using comparison tools.

Printscreen Rotor Dynamics modulePrintscreen Bearings module
Printscreen Rotor Dynamics modulePrintscreen Bearings module


History of the Development of Aerodynamic Bearings in the Czech Republic

History of the development starts in the 1980s when the State Research Institute for Machine Design (SVUSS) Bechovice in cooperation with the Research Institute for Food Processing and Refrigerating (VUPCHT) Hradec Kralove started first attempts for a gas bearing rotor support.
Application Use of aerostatic bearings was not viable due to rotor instability at higher speeds. That is why tilting pad aerodynamic bearing was developed in 1981, designed in such a way that it was possible to adjust bearing clearance during assembly and in that way reduce requirements for manufacturing accuracy.
Newer bearing design from 1982 brought also the possibility of bearing properties adaptation to operating conditions due to elastic support of a single pad (see the picture). This type of bearings enabled to achieve the projected maximum speed of 300 000 rpm.
A function model of an expansion turbine with the braking power of 1 to 2.5 kW was long-term tested in VUPCHT in 1984 and later several prototypes of turbines were supplied to He Liquefiers for the Linde Company. Around 1987, turbine production was taken over by PBS Velka Bites who supplied more than 300 turbines of different types all over the world. Operation parameters were gradually increased up to the present maximum speed close to 350 000 rpm.
In 2014, a helium expansion turbine with the breaking power of 10 kW and the maximum operating speed of 182.000 rpm was designed and successfully tested.

Turbo-Blowers/ Turbo-Circulators:
In cooperation with ATEKO Hradec Kralove (successor of VUPCHT), a number of high-speed machines with aerodynamic bearing support were designed:
  • 2000: Turbo-circulator – argon - for the CERN research centre, 2.5 kW, 35 000 to 55 000 rpm
  • 2001: Turbo-blower ATD 5000 – 5 kW, 110 000 rpm, ATD 9000 – 9 kW, 90 000 rpm (also used for very aggressive landfill gas)
  • 2003: Turbo-blower ADT3000 – 3 kW, 70 000 rpm
  • 2005: Turbo-circulator – argon -for the CERN research centre, 6.3 kW, 77 000 rpm (tested to 85 000 rpm)
  • 2009: Turbo-circulator - helium, nitrogen or mixture of He+N2 for the DIADEMO test circuit, the CEA project, 38 000 to 77 000 rpm, inlet pressure of 7.8 MPa
  • 2012: Turbo-circulator - helium, the KATHELO project, 52 000 to 75 000 rpm, inlet pressure up to 9.5 MPa
  • 2014: Turbo-circulator - helium and turbo-circulator - helium combined with an expansion turbine, the ELI project, 110 000 rpm
  • 2010: Turbo-expander for the ORC cycle, 5 kW, 50 000 to 95 000 rpm
  • 2011: Turbo-expander for the ORC cycle, 50 kW, 37 000 rpm
Bearing Support of High-Frequency Electric Motor:
In cooperation with the Institute of Thermo-Mechanics of the Czech Academy of Sciences and CKD Nove Energo
  • 2001: input 50 kW, 50 000 rpm, rotor mass 7.5 kg
  • 2004: input 100 kW, 18 000 rpm, rotor mass 50 kg
Rotor Support of Air cycle Machine:
In cooperation with PBS Velka Bites, Division of Aircraft Technique
  • 2013 : Air cycle machine with a new type of tilting pad bearings for speeds up to 60 000 rpm was designed and Applicationtested. Aerodynamic tilting pad bearings with elastic support of all pads (see picture) were used simplifying the original complex bearing design. Operation properties of these bearings are in all aspects at least comparable with those of foil bearings (used on a relatively large scale). High damping of the bearings ensures stable rotor run even in the conditions of severe external excitation.

The accumulated know-how gained from such a long history of projects has been gathered, compiled and optimized into a common knowledge base accessible in the form of the DYNROT system, which is offered by the Sobriety s.r.o. company in a price effective package.


Main DYNROT Functionalities

  • Sketch or modify a rotor system
  • Design bearing parameters
  • Compare bearing design with different designs
  • Provide sensitivity analysis for selected parameters
  • Generate bearing design report
  • Create bearing database
  • Calculate rotor dynamic parameters
  • Compare rotor dynamic design with a different one
  • Provide sensitivity analysis
  • Generate rotor dynamic design report
  • Windows 7 ready
  • Windows 8 ready
  • TouchScreen ready




The gas lubricated bearing and sealing system design module consists from the following sub-modules.

  • Aerostatic thrust bearings
  • Aerostatic radial bearings
  • Aerodynamic thrust bearings
  • Aerodynamic radial tilting pad bearings
Download PDF: History of the Development of Aerodynamic Bearings in the Czech Republic


The hydrodynamic bearing design module consists from the following sub-modules.

Journal bearings:
  • Cylindrical
  • Lemon bore
  • Offset halves
  • Multi-lobbed (three pad, four pad)
  • Tilting pad
Thrust bearings:
  • Tapered land (fixed pads)
  • Step (pocketed)
  • Tilting pad


Module for providing operational balancing. The module allows evaluation of balancing parameters based on the measurements provided by a speed sensor and shaft motion sensors or accelerometers. The module allows to process data from sensors to evaluate balancing locations. With an additional balancing hardware DBB (DYNROT BALANCING BOX) the balancing operation can be done in real time based on a speed sensor and 2 accelerometers or shaft motion sensors.


Software Overview


Assessment of technical adjustments and machine sets calculations for PVE Dlouhé stráně
The causes of the machine sets accident were reviewed and the recalculation and the review of machine sets modification, designed in Škoda ES Plzeň, were made.
Strength issue of impeller VE Dlouhé Stráně
The causes of nonsynchronous vibration and strength issue of turbo set VE Dlouhé Stráně impeller were examined theoretically and experimentally.
Development of balancing technology for expansion turbine rotors for speed up 400.000 min-1.
The complete balancing technology of 1.st rotor bending shape was formulated and validated, including realization of equipment for determination of imbalance equal phase, device for rotor’s spinning to speed up 350.000 min-1 and balancing software. The methodology was improved gradually and making more and more precise and then applied on other type of rotors.
Dynamic rotor analysis of high-speed expansion turbines and steam turbines PBS V. Bíteš
The calculation of dynamics of rotor turbines, which impellers are mounted directly on high speed gearboxes pinion, was done. Analysis of results allowed to determine the causes of higher vibration as rotor instability due to influence of labyrinth seals and optimize a design of other machines from rotor dynamics point of view.
Measurement of axial load for bearings and vibration of energy units SAFÍR, NETZ, TURBOJET a TGU100
In difficult conditions of small size and high temperature, the strain gauge measurements of loads which are acting on rotor roller bearings of units powered by combustion turbine under various operating modes were done.
Rotor dynamics in aerodynamic foil bearings
The theoretical solution of aerodynamic radial and axial foil bearings was created, the test foil bearings were designed and their properties were experimentally proved. The new type of aerodynamic bearing was developed, which connected the advantages of foil bearings and bearings with tilting segments.
Active operation of plain bearings with aim to minimalize of rotor instability
Within the grant project, the device for testing of the influence of outer excitation to rotor dynamics in plain bearings was constructed and made, maximal speed 23.000 min-1, both bearing rings can be deflected in any direction by pair of piezo actuators. The theoretical analysis of ways of excitation for removing rotor instability was created. The device was put into operation and possibility of removing instability by active operation of bearings was confirmed. Investigation of influence of active operation to rotor dynamic behavior continues in next grant project in years 2012-14.
Identification of dynamic behavior of aerostatic radial bearings
Extension Rotor Kitu Bently Nevada was designed and made, allowing the identification of stiffness coefficients and attenuation coefficients of radial aerostatic bearings through harmonic excitation in two directions. Measurement results were confronted with calculations.
Design of support and propulsion of power gyroscope
Placement of power gyroscope for speed to 40.000 min -1 alternatively in air lubricated bearings and accurate spindle bearings was designed. The propulsion of gyroscope is ensured by compressed air. Gyroscope container is placed in aerostatic bearings, which ensure minimal resistance against motion. Functional tests showed the satisfactory function of placement, but the small effectiveness of pneumatic propulsion.
Design of aerodynamic placement of argon circulator for CERN research center
Aerodynamic support of two circular blowers with power of 2,5 a 6,3 kW and operating speed more then 60.000 min-1 was designed, made and experimentally verified. The circulators ensure argon circulation in circle for particles (from LHC accelerator) detection in CERN research center.
Development of aerodynamic support of high-speed rotation blowers
The aerodynamic placement of blower rotors with power 3 to 9 kW and speed up 110.000 min-1 was designed. The machines with power 3 to 9 kW were successfully verified.
Design of aerodynamic placement of expansion turbine with power 10kW
The radial and aerodynamic thrust bearings were designed and methodology of operating balancing with correction of the 1.st rotor bending shape was created, all for expansion turbine with operating speed up 187.000 min-1.
Design of placement and dynamic rotor analysis of steam turbine EKOL Brno.
The suitable bearings were designed and dynamic rotor calculation were done for classic steam turbines with higher operating speed (from 7.000 to 14.000 min-1)
Measurement of vibration and dynamic rotor analysis of PBS Turbo turbochargers
The dynamic calculation of various turbocharges types was done. The measurement of relative rotor vibration on a several types TD with different sizes and floating rings of bearings, possibly the measurement of oil film thickness in thrust bearing and axial force, were done. Mostly all results of measurements were confronted with calculations.
Proposal of balancing methodology and vibration control of turbochargers series C1 and delivery of balancing stool
The methodology of operating balancing of small turbocharges for speed up 180.000 min-1 was proposed. Based on developed methodology and with collaboration of DIOSS Nýřany company, two semi-automatic stools, which enable vibration control and operating balancing of assembled turbochargers, were provided.
Developing of aerodynamic placement for rotation machines of higher power.
The aerodynamic placement of turbocharger rotor with power about 100 kW for speed 18.000 min-1 was designed and tested. Rotor of weight 50 kg is placed in radial tilting pad bearings of diameter 120 mm, axial forces are captured by aerodynamic thrust bearings with spiral grooves.
Gas lubricated sealing design
Aerodynamic sealing were designed, made and tested.
Reference map
Software for rotor dynamic computation according to API 617
Software for rotor dynamic computation according to API 617, 7th Edition.
Identification of causes and removing the instability of VT part of steam turbine
Strong instability of „oil whip“ rotor type possibly caused by influence of destabilization effect of labyrinth seals was reduced by decreasing of loads and exchanging of bearings. Decreasing of loads was achieved the lower rigidity of bearings, so damping of oil film can be applied. Next increasing of damping was achieved by using bearings with tilting segments which high backlash and small preload.
Recalculation of bearings with tilting segments, valorization of influence of subharmonic frequency and pliability of bearing placement.
Influence of subharmonic frequency was analyzed and also pliability of bearing segment placement on rigidity and bearings dampings of turbosets Temelín, Prunéřov, Počerady a Ledvice.
Software for computation of static and dynamic characteristic of lemon, offset and segment bearings.
For Škoda Power, new software program versions for computation of static and dynamic (rigidity and damping) characteristic of cylindrical, lemon and offset radial bearings and bearings with tilting segments were developed.
Design of placement and dynamic analysis of sets TUBBOCRON – turbocharger with VF generator
The suitable placement was designed and dynamic calculation of rotors set – turbocharger TCR12 – high frequency generator VÚES, connected by multi-plate clutch was done.
Design of aerodynamic placement of rotor turbo expanders for ORC cycles
For company Hennlich, the placement of turbo expander rotors about power 5 and 50kW in aerodynamic bearings lubricated by process medium were designed. Function of placement for both sets were tested successfully.
Calculation and dynamic characteristic measurement of boost turbocharger rotors.
The calculation of placement and rotor dynamic of turbochargers for cars Škoda and Audi were done. Computed characteristic were experimentally verified by measurement of relative and absolute vibration including an influence of rotor unbalancing.
Design of aerodynamic bearings for placement of turbo cooler
The placement of turbo cooler rotor in aerodynamic bearings with flexible placed segments was designed. Proposed placement was tested successfully and even in regimes Acceleration and deceleration. The software for aerodynamic bearings computation were given to PBS.
Aerodynamic placement of test rotor
Aerodynamic radial and thrust bearings for test rotor of Bosh company with maximal speed 200.000 min-1 were designed and made.
Dynamic parameters of manufactured bearings calculations
Calculations of bearing dynamic parameters for electric generators


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