Hydrogen Supply System for PUMAc-Fx

FLUIDON is a Partner within the Fuel Supply (FLY) sub project of the PUMAc-Fx innovation alliance.

PUMAc-Fx is the name of an innovation alliance of industrial and research partners for the design of ultra-light hydrogen gas turbine units in Aachen (Power Units Made in Aachen - Fuel X). In close cooperation between the industry and researchers, a new, climate-friendly propulsion system is being created, which - modularly constructed - is just as suitable for aviation applications, e.g. in modern air taxis, as it is for stationary power supply or as a ship propulsion system.

One of the challenges of the project is the development of an energy supply system suitable for aviation, the so-called GenSet. The GenSet comprises the components 700 bar H2 pressure accumulator, pressure reducer, valves, gas turbine, alternator, inverter and battery buffers as well as the control unit.

Fuel Supply (FLY) Sub-project

In the FLY sub-project, the hydrogen supply system of the GenSet is designed and simulated from the high-pressure tank to the gas turbine of the PUMAc-Fx units. For this purpose, FLUIDON is expanding the DSHplus component library to include the component-specific features of hydrogen supply systems.

Based on simulation models from the subprojects FLY, GTS, GPE and the load specification from SYD, a digital twin of the GenSet of the PUMAc-S unit is then built with FLUIDON's Virtual Engineering Lab (VEL), which the project partners use to develop a deeper system understanding with regard to the dynamic interactions within the GenSet.

The digital twin of the GenSet is used for simulation-based requirements analysis for actuators and control elements and for virtual commissioning of the hydrogen distribution system control and the GenSet control.

The aims of model-based development and virtual commissioning are:

  • To work interdisciplinarily to achieve a better overall quality of the product design.
  • To identify design problems earlier in the course of the project and thus be able to correct them even more inexpensively.
  • To design, test and optimise the control software even though no real hardware is available yet.
  • To shorten the commissioning time of the GenSet, giving the Innovation Alliance more time to test the demonstrator in the field.

Simulation of hydrogen pipeline systems with DSHplus

DSHplus already comes with an extensive library of pipes, valves, resistors and special components.
The piping is modelled as "1D-CFD" (as opposed to discrete 0D models), which means that high-frequency pressure waves are also captured.

The video showcases the pressure drop across a valve in a hydrogen supply system and illustrates the temperature increase in the downstream fluid due to the Joule-Thomson effect.

The simulation models take the following conservation equations into account:

  • Momentum equation ("Navier-Stokes equation")
  • Continuity equation
  • Energy equation

The equations are expressed in such a way that flows of liquids, ideal gases and real gases can be simulated.

The component models cover the following physical effects/phenomena:

  • Joule-Thomson effect (Temperature change due to isenthalpic throttling)
  • Arbitrary fluid properties (have to be provided as "characteristic maps" as a function of pressure and temperature)
  • Steady and unsteady viscous friction (Distortion of the radial velocity profile due to unsteady flow with an associated increase of pressure drop)
  • Heat transfer between fluid and environment through the pipe wall
  • Dissipative heating of the fluid due to friction
  • Transport, dissolving and degassing of gas fractions carried by the liquid
  • Impact of compliant pipe/hose walls (linear elastic, linear visko-elastic) on the apparent ("effective") speed of sound of the fluid
  • (Fluid-structure interaction)