Computational fluid dynamics study of hydrogen mixing in the intake manifold

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Volume Title

School of Engineering | Master's thesis

Date

2024-09-30

Department

Major/Subject

Energy Conversion Processes

Mcode

Degree programme

Master's Programme in Advanced Energy Solutions

Language

en

Pages

94

Series

Abstract

This study implements a simple, novel and inexpensive procedure to assess various hydrogen injection configurations to an H2-PFI (Hydrogen Port Fuel Injection) engine using the CFD software Star-CCM+. The novelty lies in the use of the ’Notional Nozzle’ concept to model under-expanded jets. The study was conducted in order to bridge the research gap of understanding the mixing of fuel and air in the intake manifold. The primary goal of the study is to understand the behaviour of hydrogen injection through a carefully designed simulation matrix, and to assess the usefulness of this model to tackle issues related to the H2-PFI ICE. The study reveals that the down-stream injection delivers mixtures of appropriate homogeneity, while maintaining a low amount of leftover hydrogen in the intake manifold. The perpendicular injection configuration falls short in both delivering homogeneous mixtures, and in terms of the hydrogen residue in the intake manifold. The up-stream injection configurations provide excellent homogeneity of air-fuel, while proving to be problematic in terms of hydrogen residue. Simulations show that performance of hydrogen injection in the geometry provided by AGCO Power is extremely sensitive to minor changes in injection location and angle. An injection configuration selected following an extensive analysis procedure is compared against a more accurate moving mesh model (In-cylinder), which reveal that the Steady-state Port Flow model is reliable in predicting certain parameters such as surface average and surface standard deviation of equivalence ratio (𝜙) of surfaces of interest, while providing inaccurate results in terms of hydrogen mass flow into individual valves and hydrogen mass residue.

Description

Supervisor

Vuorinen, Ville

Thesis advisor

Anttinen, Teemu

Keywords

hydrogen, H2-PFI, backfire, notional nozzle, steady-state port flow simulation, in-cylinder simulation, verification, JICF

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