Final Report: Experimental Studies of Hydrocarbon Flame Phenomena: Enabling Combustion Control Report Title This report summarizes the research accomplished in the project "Experimental Studies of Hydrocarbon Flame Phenomena: Enabling Combustion Control". The main areas of activity are: a) electrostatic flame and flow control, b) flame hysteresis in heated coflows, c) flame lifting and splittin...

A new modeling strategy is developed to introduce tabulated chemistry methods in LES of turbulent premixed combustion. The objective is to recover the correct laminar flame propagation speed of the filtered flame front when subgrid scale turbulence vanishes. The filtered flame structure is mapped by 1-D filtered laminar premixed flames. Closure of the filtered progress variable and the energy b...

Laminar flame speeds of undiluted syngas (H2/CO) mixtures have been studied at atmospheric conditions using chemiluminescence and schlieren techniques for a straight cylindrical burner apparatus. A wide range of mixture composition, from pure H2 to 1/99 % H2/CO, has been investigated for lean premixed syngas flames. To achieve a better flame stabilization and reduce flame flashback propensity, ...

Detailed understanding of turbulent combustion in liquid rocket engines (LRE) requires an ability to predict the coupling between the transient features, acoustics, vortex/shear layer dynamics and the unsteady combustion heat release. Conventional and ad hoc models that mimic or match one set of conditions but fail in another test case cannot be used for reliable predictions. This paper present...

New combustion systems based on ultra-lean premixed combustion have the potential for dramatically reducing pollutant emissions in transportation systems, heat, and stationary power generation. However, lean premixed flames are highly susceptible to fluiddynamical combustion instabilities, making robust and reliable systems difficult to design. Lowswirl burners are emerging as an important tech...

The objective of this study is to investigate the combustion in a pilot-ignited supercharged dual-fuel engine, fueled with different types of gaseous fuels under various equivalence ratios. It is found that if certain operating conditions are maintained, conventional dual-fuel engine combustion mode can be transformed to the combustion mode with the two-stage heat release. This mode of combusti...

Flaring of waste gases is a common practice in the processing of hydrocarbon (HC) materials. It is assumed that flaring achieves complete combustion with relatively innocuous byproducts such as CO2 and H2O. However, flaring is rarely successful in the attainment of complete combustion, because entrainment of air into the region of combusting gases restricts flame sizes to less than optimum valu...

The general objective of this project is to support the development and validation of large eddy simulation (LES) models used to simulate the response of fires to the activation of suppression systems. The focus here is on suppression by gaseous agents. The present experimental configuration is a two-dimensional, plane, buoyancydriven, methane-fueled, turbulent diffusion flame with a controlled...

This work focuses upon the effects of DC electric fields on the stability of downward propagating atmospheric pressure premixed propane–air flames under experimental conditions that provide close coupling of the electric field to the flame. With the appropriate electrode geometry, modest applied voltages are shown to drive a stable conical flame first into a wrinkled-laminar flamelet geometry, ...

In gas explosions, the unsteady coupling of the propagating flame and the flow field induced by the presence of blockages along the flame path produces vortices of different scales ahead of the flame front. The resulting flame/vortex interaction intensifies the rate of flame propagation and the pressure rise. In this paper, a joint numerical and experimental study of unsteady premixed flame pro...