V²-DoRR

Variable venturi nozzle for precise dosing of reactants in hydrogen drives for high quality of control under highly dynamic operating conditions

Both in fuel cell drives or H₂ engines and in thermochemical reactions in general, there is a great effort to increase overall efficiency. One of the essential tasks in these machines and processes is to dose the reaction gases in the reaction volumes with high precision, dynamically, and with as little loss as possible. Technologies used so far for this purpose are mostly calibrated at stationary points and therefore behaviour in changing operation is to some extent unknown. Due to highly dynamic fluidic effects, the physical conditions can only be represented with difficulty linearly - which, however, is the basis of common system calibrations.

A dosing system, for which a European patent has been applied for through BayPAT, is based on the principle of a variable venturi nozzle and includes a device for rapidly changing the effective flow cross-section. This dosing system should offer a higher degree of efficiency compare to conventional technologies.

This should be realised using diffuser technology, which enables partial recovery of the pressure losses. In addition, a flow-optimised design provides for lower losses from the outset.
The system should offer significantly higher dynamics, which in turn enables more precise control in changing operating conditions. Using a variable venturi nozzle promises high dynamics and precision at the same time, which is the basic prerequisite for use in the variable range of many applications.
The system’s application-specific design and dimensioning should provide for load or mass flow requirements and – by means of a transfer function – be associated with an effective flow cross-section. The aim is to achieve a linear actuator behaviour that enables simultaneous use of the actuator as a feedback sensor for the mass flow value.
By means of the development of simplified parameterisable equation structures and using real-time capable parameter estimation methods to determine unknown parameters, physically interpretable real-time models (digital twins) will be developed. The models will be able to adjust their parameters constantly during operation, which increases the quality of control. (Keywords: degradation behaviour, component interplay, environmental conditions)

The investigations of the team around Prof. Bikas into the dosing system’s dynamics, precision, and efficacy are supported within the framework of “Validation of research results and inventions” funding from the Bayern Innnovativ GmbH and funded by the Bavarian Ministry of Economic Affairs, Regional Development and Energy. The main focus of their work is on demonstrating the advantages over competitor products in the areas of dynamics, flow losses, quality of control, and calibration robustness.

Project leader: Prof. Georgios Bikas

Researchers: Thomas Untheim, B.Eng., Peter Weigand, M.Sc.

Project partners: Bayerische Patentallianz GmbH, Micro-Epsilon Messtechnik GmbH & Co. KG, UltraZohm, Vectoflow GmbH

Funded by: Bayern Innovativ

Funding period: January 2023 - June 2024