Paper Title

Effect of hydrogen enrichment of compressed natural gas on combustible limit and flame kernel evolution in a constant volume combustion chamber using laser ignition

Authors

Profile picture of Avinash Kumar Agarwal
Avinash Kumar Agarwal
Profile picture of Rajesh Kumar Prasad
Rajesh Kumar Prasad

Keywords

  • Laser Ignition
  • Hydrogen-Enriched Compressed Natural Gas
  • HCNG
  • Lean-Burn Combustion
  • Internal Combustion Engine
  • Emission Norms Compliance
  • Spark Ignition Engine
  • Q-Switched Nd:YAG Laser
  • Beam Profile
  • Beam Quality
  • Pulse Duration
  • Constant Volume Combustion Chamber
  • CVCC
  • Air-Fuel Ratio
  • Lean Flammability Limit
  • Hydrogen Enrichment
  • Flame Kernel Evolution
  • Pressure-Time History
  • Start Of Combustion
  • SoC
  • Chamber Filling Pressure
  • Knocking
  • Two-Stage Combustion
  • Combustion Duration
  • CD
  • Flame Kernel Displacement
  • Volumetric Combustion
  • Optical Diagnostics
  • Schlieren Imaging

Journal

Fuel External link

Research Impact Tools

DOI

DOI Icon 10.1016/j.fuel.2021.121112

Publication Info

Volume: 302 | Pages: 121112

Published On

October, 2021

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Abstract

Laser ignition of hydrogen-enriched compressed natural gas (HCNG) enables lean-burn combustion, a key technology for future emissions norms compliance for internal combustion (IC) engines. HCNG overcomes the limitations of low volumetric energy density and lowers the flame speed of CNG fueled spark ignition (SI) engine-powered vehicles. In this study, laser beam profile and beam quality (M2) of a Q-switched Nd: YAG laser at fundamental wavelength of 1064 nm, having 6–9 ns pulse duration, were characterized. During the Constant volume combustion chamber (CVCC) experiments, relative air-fuel ratio (λ) of different HCNG blends were varied to identify the lean-burn limits, and observe flame kernel evolution, pressure–time history, and detect the start of combustion (SoC). At 10 bar initial chamber filling pressure, lean flammability limit increased due to hydrogen (H2) enrichment of CNG. It was found to be λ = 1.6, 1.8, 1.9, 2.0, and 2.1 for CNG, 10HCNG (10% v/v hydrogen and balance CNG), 20HCNG, 30HCNG, and 40HCNG respectively. Flame kernel displacement (Early stages of flame initiation and its development in µs time-scale) was the highest for λ = 1.1 for all HCNG mixtures, irrespective of the test fuel composition. Knocking or two-stage combustion increased with lowering λ at 10 bar initial chamber filling pressure. SoC advanced and combustion duration (CD) decreased with increasing H2 enrichment of CNG. Increased H2 enrichment of CNG accelerated the flame kernel evolution and made it a predominantly a 3D combustion phenomenon (volumetric combustion). Lower λ and higher H2 enriched CNG mixtures were effective in reducing the CD.

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