On the response of ultra-lean combustion of CH4/H2 blends in a porous burner to fluctuations in fuel flow - An experimental investigation

Habib, R., Yadollahi, B., Saeed, A. , Doranehgard, M. H. and Karimi, N. (2021) On the response of ultra-lean combustion of CH4/H2 blends in a porous burner to fluctuations in fuel flow - An experimental investigation. Energy and Fuels, 35, pp. 8909-8921. (doi: 10.1021/acs.energyfuels.1c00081)

Abstract

Fluctuations in the fuel flow rate may occur in practical combustion systems and result in flame destabilization. This is particularly problematic in lean and ultralean modes of burner operation. In this study, the response of a ceramic porous burner to fluctuations in the flow rate of different blends of methane and hydrogen is investigated experimentally. Prior to injection into the porous burner, the fuel blend is premixed with air at equivalence ratios below 0.275. The fuel streams are measured and controlled separately by programmable mass flow controllers, which impose sinusoidal fluctuations on the flow rates. To replicate realistic fluctuations in the fuel flow rate, the period of oscillations is chosen to be on the order of minutes. The temperature inside the ceramic foam is measured using five thermocouples located at the center of the working section of the burner. The flame embedded in porous media is imaged while the fuel flow is modulated. Analysis of the flame pictures and temperature traces shows that the forced oscillation of the fuel mixture leads to flame movement within the burner. This movement is found to act in accordance with the fluctuations in methane and hydrogen flows for both CH4(90%)–H2(10%) and CH4(70%)–H2(30%) mixtures. However, both fuel mixtures are noted to be rather insensitive to hydrogen flow fluctuation with a modulation amplitude below 30% of the steady flow. For the CH4(70%)–H2(30%) mixture, the flame in the porous medium can be modulated by fluctuations between 0 and 30% of steady methane flow without any noticeable flame destabilization.

• Item Type: Articles
• Additional Information: N. Karimi and B. Yadollahi acknowledge the financial support of Engineering and Physical Science Research Council through grant EP/N020472/1.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Habib, Mr Rabeeah and Yadollahi, Dr Bijan and Karimi, Dr Nader and Saeed, Mr Ali
• Authors: Habib, R., Yadollahi, B., Saeed, A., Doranehgard, M. H., and Karimi, N.
• College/School: College of Science and Engineering > School of Engineering; College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: Energy and Fuels
• Publisher: American Chemical Society
• ISSN: 0887-0624
• ISSN (Online): 1520-5029
• Published Online: 04 May 2021
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Energy and Fuels 35: 8909-8921
• Publisher Policy: Reproduced under a Creative Commons licence

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
172394		Thermally Driven Heat Pump Based on an Integrated Thermodynamic Cycle for Low Carbon Domestic Heating (Therma-Pump)	Zhibin Yu	Engineering and Physical Sciences Research Council (EPSRC)	EP/N020472/1	ENG - Systems Power & Energy