Research Highlights

Research Interests

Combustion Chemistry, Optical Diagnostics, Chemical Kinetics, CFD, Gas Turbine combustion, Chemical looping combustion, Fire Safety

Spray-Flame Interaction in Counterflow Configuration

Fire-related hazards plague modern society. The development of clean, efficient fire extinguishers has been taken up as the key project for my Ph.D. thesis.

The effectiveness of finely atomized water mist and aqueous alkali solutions are evaluated in a counterflow configuration.
Ten different salts containing sodium and potassium compounds are tested. Potassium bicarbonate and potassium acetate are identified as most effective.
Comprehensive numerical modeling under the WMG framework supports experimental findings.

DIVE DEEPER: Resource 1 Resource 2

Strain Rate Reduces Chemical Inhibitor Effectiveness

Chemical Inhibitors are the most effective fire suppressants. Phosphorus (ABC Powder) or Potassium (Purple-K) based inhibitors are ubiquitous. We report that these inhibitors lose their effectiveness at regions of large velocity gradients (strain rate).

Effect of strain rate investigated on five different chemical inhibitors (Iron, Potassium, Sodium, Phosphorus, Bromine) using CHEMKIN and CANTERA.
Except for Bromine, all inhibitors lose their effectiveness at high strain rates.
The same conclusion was obtained from flame modeling (Counterflow) and reactor modeling (PSR).

DIVE DEEPER: Research published in the Proceedings of the Combustion Institute.

Skeletal/Global Mechanisms to Describe Flame Inhibition by TMP

Efforts have been undertaken to develop short chemical kinetic models to describe flame inhibition by phosphorus-based additives.

Two short mechanisms (4 species, 7 reactions, and 3 species, 3 reactions) are proposed.
Short mechanisms are validated in laminar burning velocity, extinction strain rate, minimum extinguishing concentration, major and minor species concentration.
82% reduction in computational time achieved with respect to the detailed mechanism.

DIVE DEEPER: Resource

Reducing Preheat Temperature: Transition to Instability - Nonlinear Dynamic Studies

Combustion noise generated in a Stagnation Point Reverse Flow (SPRF) combustor showed a sudden increase in decibel level as the oxidizer preheat temperature was reduced (Experiments were conducted by Dr. Santanu Pramanik). We (Atanu and I) analyzed the pressure signal to obtain evidence of combustion instability.

Evidence of combustion instability established through nonlinear dynamic analysis (Doughnut shaped phase portrait, Low correlation dimension, High degree of determinism in Recurrence Plots).
Determinism and Median K-value from the 0-1 test are identified as suitable markers for the onset of combustion instability.

DIVE DEEPER: Resource

Extinction Characteristics of Biofuels - MethylFuran, DimethylFuran

Detailed simulations containing hundreds of species and thousands of reactions are conducted to obtain extinction characteristics of methylfuran, dimethylfuran, and their blends with isooctane. Simulations are in good agreement with experimental data generated in-house (Experiments conducted by Dr. Amrit Sahu.)

MF shows the highest resistance to extinction, followed by iso-octane and DMF.
Tianjin mechanism displays better predictive ability than the Galway mechanism.

DIVE DEEPER: Research published in Energy and Fuels.

Application of Metaheuristic Algorithms to Reaction Mechanism Optimization

The Genetic algorithm is often used to optimize detailed/skeletal reaction mechanisms. However, the performance of GA depends sensitively on the input parameters. We search the literature for parameter-free metaheuristic techniques and compare the performance with GA. This is ongoing work.

Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Teaching-Learning Based Optimization (TLBO), Artificial Bee Colony Algorithm (ABC) are compared.
Hydrogen, methane, and ammonia mechanism are optimized.
GA and PSO are highly sensitive to input parameters.
TLBO and ABC are parameter-free. Performance of TLBO is best among the tested algorithms.

DIVE DEEPER: Resource

Reaction Zone Characterization in a Swirl-Stabilized Combustor using OH-PLIF

Reaction zone visualization in a swirl-stabilized combustor using OH-PLIF is conducted to assess the performance of a 26 kW two-stage combustor using syngas as fuel. The accompanying picture is taken in a rich Bunsen flame. A strong OH signal is found in the outer diffusion flame, whereas the rich premixed inner cone emits a weaker signal.

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