This book focuses on developing strategies for ultra-lean combustion of natural gas and hydrogen, and contributes to the research on extending the lean flammability limit of hydrogen and air using a hot supersonic jet. The author addresses experimental methods, data analysis techniques, and results throughout each chapter and:

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  Explains the fundamental mechanisms behind turbulent hot jet ignition using non-dimensional analysis

  
  


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  Explores ignition characteristics by impinging hot jet and multiple jets in relation to better controllability and lean combustion

  
  


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  Explores how different instability modes interact with the acoustic modes of the combustion chamber.

  
  

This book provides a potential answer to some of the issues that arise from lean engine operation, such as poor ignition, engine misfire, cycle-to-cycle variability, combustion instability, reduction in efficiency, and an increase in unburned hydrocarbon emissions. This thesis was submitted to and approved by Purdue University.