Simulation has become increasingly important in recent years for automotive and turbocharger development. Simulation is commonly referred to as “CAE” (computer aided-engineering) and incorporates the aid of computers when performing engineering related tasks and activities. With our advanced CAE software and dedicated methodologies at Mitsubishi’s turbocharger division, we are able to virtually assess the performance and durability of our turbocharger designs by simulation.
Why apply CAE?
The insights gained through simulation provide us with the opportunity to identify and optimize critical design parameters before expensive physical testing on gas benches or in customer vehicle tests. The availability of simulation within engineering significantly reduces the lead time for turbocharger development. Furthermore it minimizes the amount of physical test loops typically required during the development of turbochargers for customer application. By doing so, we are able to provide ‘tailor made’ turbocharger solutions to sophisticated OEM customer engine applications.
How does it work?
After the initial process of turbocharger ‘matching’, i.e. after defining the initial build size and type for the customer’s engine application, an initial 3D design proposal is prepared using CAD. From CAD, the generated geometry will be prepared or discretized for subsequent CAE. Afterwards, the CAE process can either involve computational fluid and/or solid mechanics depending on the design phase and status. For example, customer packaging requirements occasionally dictate the application of a strong pipe bend in front of the turbocharger’s compressor inlet. As one can expect, such an influential piping modification will have a strong effect on overall compressor performance. By applying simulation, i.e. computational fluid mechanics (or so-called CFD) in combination with a 3D model, our simulation engineers can assess the expense in compressor performance as a result of the pipe bend within a virtual environment. Secondly, the insight gained through simulation is used to determine the optimum between packaging restrictions, piping geometry and compressor performance. As a result the final design proposal will meet the customer’s packaging requirement with a minimum drop in overall performance.
Another frequent challenge at Mitsubishi’s turbocharger division is the development of durable turbine designs. Nowadays more stringent emission legislation is driving our customers to develop even more efficient engines. As a result, engine operating temperatures are increasing which in turn; impose increasing thermal loads on critical turbocharger components like turbines. In order to design for turbine durability, we apply extensive simulation activities in order to assess a turbine housing design with respect to its thermo-mechanical fatigue characteristics. Using computational fluid mechanics (‘CFD’) for heat transfer analysis in combination with computational solid mechanics (often designated as ‘FEM’), we are able to predict turbine housing design durability quite accurately by means of simulation. The result is that turbine housing designs are optimized for durability without a significant penalty in increasing costs due to unnecessary application of high volume-percentage alloying elements like nickel.
What specifically can we offer?
The success (i.e. accuracy) of simulation highly depends on the combination of applied boundary conditions, quality of geometry and methodology. Advanced commercial CAE codes are widely available nowadays. However, CAE methodologies have to be developed and their quality depend highly on the experience, skill and knowledge of the people using it. Over the years, we have gained a lot of experience at MTEE with simulation through the design of many high-end and sophisticated OEM turbocharger designs for our customers. We continuously develop and improve our proprietary CAE methodologies. Examples of CAE activities we can offer at our company:
- 0D/1D analysis of engine – turbocharger interaction (‘matching’),
- fluid and thermal analysis using 1D and 3D computational fluid dynamics (‘CFD),
- structural stress/strain, fatigue analysis based upon finite element modeling (‘FEM’),
- multibody dynamics (‘MBD’),
- multi-physics or fluid-structure interaction analysis (‘FSI’).