Rotor-Dynamic Analysis of the High Speed Turbo-Generator



Triogen is a supplier of ORC (Organic Rankine Cycle) systems, who has successfully incorporated world class technology into a reliable standardized innovative product. Our mission is “to deliver a meaningful contribution to the solution of global warming and the energy problem, by offering our solutions for cost effective and environmentally friendly generation of electricity from waste heat”.

Triogen was established in 2001. The development of the ORC was done in cooperation with partners which include Lappeenranta University of Technology, the University of Technology in Delft, the University of Twente, TNO, the National Aerospace Laboratory NLR and a number of other knowledge institutions. Triogen is active throughout Europe in conjunction with various partners. The business operates from its offices in Goor, The Netherlands and employs 22 full-time highly educated commercial and technical staff. Triogen is young and dynamic company with lots of opportunities for personal development.

The Triogen ORC is a standardized product in the 160 kWe power class. Energy input is waste or residual heat, as can be found in the exhaust flow of gas- and Diesel engines, combustors of wood and other biomass, and various industrial processes. The electricity is produced from heat-energy that would otherwise be wasted or degraded. The key component of the Triogen ORC is the proprietary High Speed Turbo-Generator (HTG). A typical ORC plant further consists of heat exchangers, piping and valves, a control and safety system and provisions to connect the unit to the heat source.

Triogen welcomes the contribution of students at different levels for internships and other assignments. Further information can be obtained from Triogen:


The key component of the Triogen ORC is the proprietary High-speed Turbo-Generator (HTG). The vertically positioned rotor of the HTG consists of the generator-rotor between two bearings, with at the lower side the overhung turbine-wheel and at the upper side the overhung pump-wheel. This rotor operates at a speed around 25.000 rpm. At various stages during the development of the system, the dynamic behaviour of this rotor was analysed, especially in combination with the currently used bearings.

As alternative bearing types are being sought for, there is a need to have a generic model available, where characteristic bearing data (i.e. stiffness and damping) can be incorporated. Of course, stiffness and damping of the support structure has to be taken into account also.


The objective of this project is to develop and validate a generic rotor dynamics model in which bearing and support properties can be varied. The model must be validated with vibration measurements on the system, and the feasibility of using this data for condition monitoring (e.g. early warnings) will be investigated. Also the use of historic data on existing machines (operating for several years) to characterize the vibration patterns in an empirical manner will be investigated. Finally, the developed model will be used to investigate the sensitivity of the dynamic behavior for:


Bearing stiffness and damping


Support stiffness and damping


Other bearing and support characteristics like clearances, misalignment


Excitation by seals and parasitic flows


Influence of changing the dimensions (diameter, height and mass) of the turbine-wheel


the possible occurrence of sub-synchronous whirl


Mechanical engineering


The work has to be executed at the Triogen office and / or the university depending on what is practical in view of the different phases. Eventually it can be combined with a separate Internship. Estimated duration is 6 - 10 months.

More information on the assignment can be obtained from:

T. Tinga ( / R. Loendersloot (

Ir. Quirijn Eppinga, CTO or Prof. Ir. Jos van Buijtenen, Founder / Advisor.