Accession Number : ADA621673


Title :   Local Limit Phenomena, Flow Compression, and Fuel Cracking Effects in High-Speed Turbulent Flames


Descriptive Note : Final rept. 1 Mar 2013-28 Feb 2015


Corporate Author : CONNECTICUT UNIV STORRS DEPT OF MECHANICAL ENGINEERING


Personal Author(s) : Lu, Tianfeng ; Ren, Zhuyin ; Chen, Jacqueline H


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a621673.pdf


Report Date : 01 Jun 2015


Pagination or Media Count : 24


Abstract : The objective of the proposed research is to understand the roles of local limit phenomena, e.g. local extinction and reignition, interactions between flow compression and fast-reaction induced dilatation (reaction compression), and to identify the rate-limiting fuel oxidation pathways in high-speed turbulent flames. To achieve this objective, systematic computational diagnostics were developed and performed based on elementary flames and turbulent flames simulated with direct numerical simulations (DNS). During the current reporting period, progress has been made in the following tasks: 1) Computational diagnostics were developed to identify local ignition and extinction and reaction fronts in turbulent flames simulated using DNS. 2) Effects of surrogate jet fuel composition and fuel cracking reactions on high temperature combustion were studied using a bifurcation analysis. 3) Reduced mechanisms for high-temperature combustion of n-butane and n-dodecane with lumped fuel cracking reactions were developed and validated. 4) 2-D DNS was performed to investigate the fuel cracking effects in high temperature and strongly turbulent premixed flames. 5) A highly efficient ODE solver, dynamic adaptive hybrid integration, was developed for stiff chemistry.


Descriptors :   *COMBUSTION , *COMPUTER AIDED DIAGNOSIS , *FLAMES , *HIGH TEMPERATURE , *JET ENGINE FUELS , BIFURCATION(MATHEMATICS) , BUTANES , CHEMICAL REACTIONS , COMPOSITION(PROPERTY) , COMPRESSION , CRACKS , DODECANE , DYNAMIC RESPONSE , EIGENVALUES , HYBRID SYSTEMS , IGNITION , STIFFNESS


Subject Categories : Physical Chemistry
      Thermodynamics
      Combustion and Ignition


Distribution Statement : APPROVED FOR PUBLIC RELEASE