CFD Analysis of Knocking in Hydrogen-Fueled Spark-Ignition Engines with Large Eddy Simulation and Conjugate Heat Transfer Mitsubishi Heavy Industries, Limited

Format:

Book

Conference/Event

Author/Creator:

Nomura, Kazutoshi, author.

Contributor:

Fuse, Azusa

Imamori, Yusuke

Nakano, Hiroki

Oda, Yuji

Suzuki, Keita

Suzuki, Yasumasa

Tsujimura, Taku

Conference Name:

SAE Energy and Propulsion Conference (2025-10-14 : Ypsilanti, Michigan, United States)

Language:

English

Physical Description:

1 online resource cm

Place of Publication:

Warrendale, PA SAE International 2025

Summary:

In the pursuit of a carbon-neutral society, hydrogen-fueled power generation engines are gaining considerable attention. However, knocking remains a significant problem that hinders efficiency improvements in hydrogen-fueled spark-ignition (SI) engines.In particular, the large displacement engines, such as those used in cogeneration and distributed energy sources, often face issues with knocking. This is because, with a larger bore and lower rotational speed, there is a higher risk of auto-ignition occurring before the flame has spread throughout the combustion chamber.Knocking is a complex phenomenon influenced by several interrelated physical factors:1) Flow: the non-uniform distribution of fuel concentration and flow velocity within the cylinder; 2) Combustion: the non-uniform propagation of flames affected by the mixture's concentration and flow velocity distribution; 3) Heat Transfer: the non-uniform temperature of the unburned mixture resulting from the temperature distribution of the combustion chamber surface; and 4) Reaction: variations in reaction rates at different locations due to localized temperature differences in the unburned mixture.This study presents a detailed computational fluid dynamics (CFD) analysis method that integrates cycle-to-cycle variations using large eddy simulation (LES) and accounts for local wall temperature distributions by conjugate heat transfer (CHT) to investigate knocking. The CFD model effectively predicts the in-cylinder heat release rate and knocking frequency. The findings reveal that gas temperature, wall temperature, and velocity distribution within the combustion chamber significantly contribute to the occurrence of knocking. Specifically, the analysis indicates that the mixture near the hot spot between the exhaust valves ignites, and that cycle-to-cycle variations in flow velocity near the spark plug lead to cycle-to-cycle variations in heat release rate, resulting in knocking

Notes:

Vendor supplied data

Publisher Number:

2025-01-0389

Access Restriction:

Restricted for use by site license