Challenges in Designing Components for Hydrogen Systems

Given the unique nature of hydrogen and the demanding environments in which these components operate, they must be designed to guarantee:

1. Precision Flow Control
   • Achieving accurate regulation of hydrogen flow and pressure to ensure system efficiency and performance.
2. Wide Range of Operating Conditions
   • Adapting to extreme pressures and temperatures across various hydrogen applications.
3. Dynamic System Integration
   • Ensuring seamless operation within larger systems, such as propulsion, storage, or transportation networks.
4. Safety and Reliability
   • Preventing high-pressure peaks and complying with stringent industry safety standards.

Simcenter Amesim is the go-to simulation tool for design of components used across various hydrogen applications: Small Pressure Regulators, for precise control in fuel cell systems and storage tanks, Compression Systems, managing flows and pressures in refueling stations, Large Transportation Valves, ensuring safe and efficient hydrogen distribution across pipelines.

It offers capabilities that address challenges at both the component and system levels:

1. Geometric-Level Modeling

• Model valve behavior with detailed geometrical precision, as shown in Figure 1 where the model of a H2 pressure regular is considered, including: Orifice shapes, spring dynamics, and flow paths. Fluid interactions with mechanical components affecting valve response
• Evaluate how geometry impacts flow characteristics, fluid temperature, pressure drops, and performance.
• Optimize the behaviour of the valve by exploring different combinations of geometric parameters.

Figure 1: Simcenter Amesim model of a pressure regulator.

2. Real Gas Behavior Simulation

• Simulate hydrogen as a real gas under high pressures using advanced equations of state (EoS). In Figure 2, results obtained for different gas models available in Simcenter Amesim are plotted against experimental data considering the pressure regulator mentioned in the previous section.
• Accurately predict the effects of compression, flow dynamics, and temperature changes.

Figure 2: evolution of pressure downstream the regulator, different gas models are considered

3. Integration in complex multi domain System Simulations

• Model hydraulic components as part of larger hydrogen systems, such as:
  1. Compression systems for refueling stations
  2. Storage tanks
  3. Propulsion systems for fuel cell vehicles
  4. Transportation pipelines and networks
• Test how valve performance affects overall system efficiency and safety
• Discover the natural frequencies which characterize the pipings and prevent the rise of potential resonance phenomena before the components are built and integrated in the system.

Figure 3: valves in a hydraulic network for hydrogen storage

In Figure 3, valves are used in a storage system in which different tanks are present; this storage layout is common in many applications related to hydrogen, for example, it is used in skids.
The opening/closing of the valves are controlled by signals, thus this model can be used to test different control strategies.
The dynamic effects (such as pressure peaks, change in mass flow rate, etc.) due to the valve opening/closing are properly predicted by our model.

4. Dynamic Analysis of Working Conditions

• Simulate valve behavior under varying conditions, including:
  • High-frequency opening and closing cycles.
  • Sudden pressure surges and transient events.

Understanding how flow rate and temperature respond to pressure variations is crucial for optimizing valve performance in hydrogen systems.

Figure 4: multi-physics model of a hydrogen injector in Simcenter Amesim

In Figure 4, the multi-physics model of a hydrogen injector for automotive applications is shown. Conventional direct injectors have typically inwardly opening needles. But unfortunately, for a medium pressure H2 injector, the latter needle type will be the origin of some sealing problems: it is indeed prone to be opened by the cylinder pressure which will be higher than the pressure inside the injector. Consequently, a potential back flow towards the injector would cause severe safety concerns. To tackle this particular problematic, a typical solution adopted by some suppliers of the automotive sector is to replace the conventional design by an outwardly opening injector type, which is then naturally sealed by the high cylinder pressure.
The pneumatic part is interacting with the electromechanical solenoid which control the position of the needle of the injector and with the pneumatic circuit.

Figure 5: dynamic evolution in time of pressure downstream the nozzle of the injector

5. Optimization and Virtual Testing

Case Study: OMB Saleri optimizes Valve Design with Simcenter Amesim

A leading valve manufacturer, OMB Saleri uses Simcenter Amesim to model and optimize their pressure regulator for hydrogen propulsion systems. Here’s how they succeeded:

1. Geometric Modeling:
   • Developed a detailed model of the valve geometry, including internal flow paths and spring mechanisms.
   • Simulated flow and pressure dynamics to identify areas for improvement.
2. System Integration:
   • Tested the valve within a propulsion system model, evaluating its interaction with fuel cell components.
3. Dynamic Performance:
   • Simulated transient events to ensure stable valve response under varying operating conditions.
4. Results:
   • Reduced pressure drops by 15%.
   • Improved valve response time by 20%.
   • Ensured compliance with hydrogen safety standards.

Read more about the Success Case here

Simcenter Amesim: the Competitive Advantage for Fluid Management Components

Fluid management components are critical to the success of hydrogen systems, and their design must balance precision, safety, and efficiency.

Simcenter Amesim offers unmatched capabilities to design and optimize them:

• Preconfigured Libraries: Models for valves, hydrogen components, and fluid systems.
• Multiphysics Simulation: Seamlessly integrates mechanical, fluid, and thermal analyses.
• Intuitive Interface: Simplifies configuration and accelerates validation.
• Advanced Optimization Tools: Enables parameter tuning to meet efficiency and safety goals.

By leveraging its advanced simulation capabilities, valve manufacturers can reduce development costs, accelerate innovation, in demanding hydrogen applications.

If you’re ready to elevate your valve design capabilities, contact us for a personalized demo of Simcenter Amesim.