Thermo Fluid Systems



Introduction

The term thermo fluid systems is used for systems that make use of the principles of both thermodynamics and fluid dynamics. This kind of system is essential on modern airplanes: Air of the right pressure, temperature, moisture and amount is needed to accomodate passengers, pressurize the cabin and cool electric components.

To this end, air is bled from the compressor stages of the turbo fan engines. In a multi-stage-process, this air is compressed, cooled down, dehumidified, and finally expanded.

These air conditioning and cooling systems are commonly referred to as Environmental Control Systems or Air Management Systems.

For control and design of these components, exact but computationally efficient models of the complete system are needed.

The team Energy Systems deals with the development and improvement of these models. On this basis, system architectures are designed and optimized. The main research areas are

  • Architecture- and System Optimization
  • Model Initialisation
  • Data-Mining / Classification
  • Model Fitting
  • Co - Simulation
 
 

Modeling

The most important goal during the development of new models is to find an adequate balance between accuracy and complexity. To reach this goal it is necessary to get a comprehension of the system on a physical level, and then to identify and integrate the most important influences into the model.

thermofluid2_600

In the team Energy Systems the implementation is mainly done in the object-oriented modeling language Modelica.

Control design

A variety of approaches is available when it comes to the design of new controllers. In any case, the system dynamics first have to be specified in an adequate system model. This can be done via direct physical modeling. Another possibility is to construct a co-simulation environment, where a part of the model is simulated by a cfd-tool. Afterwards, the actual control design is executed.

 

Design Environment New ECS

Depending on the design of a given aircraft, the positions from which bleed air for the environmental control- and cooling systems is extracted are limited. Based on this limitation, the subsequent reduction in pressure and temperature is not quite efficient. This could be remedied by the use of electrified system architectures.

thermofluid6_600

The team Energy Systems develops a framework for the design and evaluation of such systems (รจ architecture and system optimization). This enables global optimization of the complete system via the evaluation of aircraft-level-parameters like fuel consumption.

 


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