Development of a novel CFD method for accurate heat transfer analysis of continuous variable transmissions (CVT)

Johannes Wurm, Christoph Hochenauer, Matthias Fitl

Research output: Contribution to conference(Old data) Lecture or Presentationpeer-review


The presented work focuses on convective heat transfer effects regarding a continuous variable transmission (CVT). Due to the fact, that the belt life span of rubber V-belt driven CVTs is drastically decreasing when temperatures are rising, a sufficient cooling system is indispensable to reduce local peak temperatures. So far, only analytical models to predict the power loss of a CVT and multi-body simulations have been published. In the open literature hardly anything is available that deals with thermal investigations of CVTs.
In this work, a new method is developed to predict surface temperatures of various components and to compute the heat transfer from the hot pulleys to the surrounding airflow. Using computational fluid dynamics (CFD) simulations, enables an insight into the behaviour of the system and allows an evaluation of various parameters.

Transient simulations are highly time consuming, thus a steady-state simulation model is preferable. A steady-state method, which is capable to compute the heat transfer of a heated rotating disk in an asymmetric airflow field accurately, does not exist so far. For the modelling of a running CVT, this aspect is of special interest because local heat input strongly affects the resulting surface temperatures. Beside of modelling motion also the method how to induce heat in the simulation is of special interest and two different approaches are presented.
The developed method is a thermal extension of the state of the art moving reference frame (MRF) approach. If the presented method is applied, the simulation predicts reasonable surface temperatures of the pulleys which is confirmed by online measurements conducted on an engine test rig. The comparison shows excellent agreement between measurements and simulation results.
Subsequently, the developed tool is used for parameter and design studies due to its low computational cost and its reliability. The method can also be applied for any task with similar boundary conditions.
Original languageEnglish
Publication statusPublished - 18 Oct 2016
EventSAE 2016 Thermal Management Systems Symposium - Phoenix, United States
Duration: 18 Oct 201620 Oct 2016


ConferenceSAE 2016 Thermal Management Systems Symposium
Country/TerritoryUnited States


  • CFD
  • CVT

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