Simulations for JP-8 Mechanism Optimization and Validation

Principal Investigator: Jason Martz, University of Michigan, jmartz@umich.edu
Faculty: Angela Violi, George Lavoie, Andre Boehman, Margaret Wooldridge, University of Michigan
Marcis Jansons, Wayne State University
Student: Shuqi Cheng, Ung Hee Lee, University of Michigan
Government: Peter Schihl, U.S. Army TARDEC
Tim Edwards, Air Force Research Lab.
Industry: James Anderson, Ford Motor Company
Peter Attema, Daimler Trucks Powertain Engineering

The objective of the current work is the generation of a validated reduced kinetic mechanism (with ~ 200 – 300 species) for use with JP-8, IPK and S8 fuel surrogates to enable predictive computational fluid dynamics (CFD) engine simulations for future US Army engine designs. In particular, this work will optimize select low temperature heat release (LTHR) and negative temperature coefficient (NTC) reaction rate parameters involving hydrocarbon species with carbon number larger than C4 to better predict experimental LTHR and NTC ignition delays. The existence of such an improved mechanism will lead to more accurate CFD models and improved Diesel engine designs with reduced experimental engine development efforts.

This work builds upon the surrogate optimizer developed by the principals [2] with TARDEC funding to match the physical and chemical properties of JP-8, IPK and S8 fuels. Our developed surrogate palette consists of four pure molecules: n-dodecane, iso-cetane, decalin, and toluene for conventional JP-8, along with the linear alkanes n-decane and iso-octane to represent the dominant linear alkane compositions of IPK and S-8 [1]. Our JP-8 surrogates have been experimentally validated in constant volume spray bombs [1] and engines [3, 4] with low ignition timing errors – recent results in [1] show less than ~ 1 point DCN error [1]. Given these encouraging results, our efforts have shifted to the evaluation and improvement of chemical mechanisms for both the neat JP-8 palette components and JP-8 surrogate mixtures [1].

The primary motivation for this project, and the "cluster" of projects of which this one project is a component, is the need to develop predictive simulation capabilities for IC engine combustion to enable the design of next generation engines and to account for continuing shifts in fuels on which these engines rely. This group of overlapping, integrated projects will be referred to as the "JP-8 Combustion Chemistry Cluster," where the value to TARDEC from clustering is that by engaging in an integrated group of projects, funding will be leveraged and the value (i.e., outcomes) will be amplified. As such, the cluster represents a multi-faceted initiative that will achieve a significant outcome to advance the state of the art for the simulation of ground vehicles and provide an important deliverable – a validated and common reduced kinetic mechanism (with ~ 200 – 300 species) for use with JP-8, IPK and S8 fuel surrogates to enable predictive engine simulation for future US Army engine designs. Such a mechanism does not currently exist.

Linked with ARC Project "Combustion Chemistry of Jet Fuels: from Atomistic Simulations to Mechanism Development"

Publications:

  • D. Kim., J. Martz, A. Abdul-Nour, X. Yu, M. Jansons and A. Violi. "An inclusive six-component surrogate for emulating the physical and chemical characteristics of conventional and alternative jet fuels and their blends." Submitted to Combustion and Flame.

References:

  1. D. Kim, J. Martz and A. Violi, Submitted to Combustion and Flame (2015).
  2. D. Kim, J. Martz and A. Violi, Combustion and Flame 161 (2014).
  3. X. Yu, X. Luo, M. Jansons, D. Kim, J. Martz and A. Violi, SAE International Journal of Fuels and Lubricants 8 (2015).
  4. D. Kang, D. Kalaskar, D. Kim, J. Martz, A. Violi and A. Boehman, Fuel 184 (2016).