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High speed Schlieren video and pressure trace analyses were used to study the turbulence effects on burning velocities in a constant volume combustion chamber. Propane-air and methane-air mixtures of equivalence ratios between 0.75 and 0.96 were ignited at 101 kPa and 296 K. Schlieren images of flame growth were recorded on video at 2000 frames per second while combustion chamber pressure was simultaneously recorded. Turbulence at ignition was up to 7 m/s intensity with 2 mm or 8 mm integral scale, produced by pulling a perforated plate across the chamber prior to ignition. In the analysis, the turbulence parameters during combustion were adjusted for the effect of decay and rapid distortion in a closed chamber. Results of both video and pressure trace analyses show a linear relationship between turbulent burning velocity and turbulence intensity as expected.

The different roles played by small and large eddies in engine combustion were studied. Experiments compared natural gas combustion in a converted, single cylinder Volvo TD 102 engine and in a 125 mm cubical cell. Turbulence is used to enhance flame growth, ideally giving better efficiency and reduced cyclic variation. Both engine and test cell results showed that flame growth rate correlated best with the level of high frequency, small eddy turbulence. The more effective, small eddy turbulence also tended to lower cyclic variations. Large scales and bulk flows convected the flame relative to cool surfaces and were most important to the initial flame kernel.

The effects of turbulence on 60% stoichiometric, premixed methane-air flame propagation were investigated using high speed schlieren video and pressure trace analyses. The mixtures were centrally spark-ignited at 300 K and 101 kPa in a 125 mm cubical chamber. Turbulence was up to 2 m/s intensity with 2 to 8 mm integral scale. With quiescent mixtures, buoyancy convected the slow-burning flame upward onto the upper wall, resulting in dramatic heat loss. With turbulence, the burning rate was enhanced profoundly, though partial flame quenching resulted in cyclic variability at higher turbulence levels. Despite this partial quenching, these ultra-lean flames generally resisted total extinguishment over the conditions tested.

Magnesium AZ80 is a medium strength alloy with good corrosion resistance and very good forging capability which offers an affordable commercial alternative to the Mg ZK60 alloy used for wheels in racing cars. Extending the market of Mg AZ80 alloy to automotive wheels requires a better understanding of macro- and micro-properties of this structural material, especially its forging behaviour. In this study the deformation behaviour of Mg AZ80 alloy is characterized by uniaxial compression tests from ambient to 420°C at a variety of strain rates using a Gleeble 1500 simulator. A constitutive relationship coupling materials work hardening and strain rate and temperature dependences is calibrated based on test results. This flow behaviour is input into a finite element model to simulate the forging operation of an automotive wheel with ABAQUS codes.

High speed schlieren video and pressure trace analyses were used to study the effects of turbulence on burning velocity in a fixed volume combustion chamber. Lean methane-air mixtures of equivalence ratios of 0.76 and 0.96 were ignited at 1 atm and 23°C. Schlieren images of flame growth were recorded on video at 2000 frames per second while combustion chamber pressure was simultaneously recorded. The turbulence intensity at ignition was set at 0 m/s to 4 m/s intensity with integral scale around 7.6 mm by pulling a perforated plate across the chamber prior to ignition. In the analysis, the turbulence parameters were adjusted for the effect of decay and rapid distortion in a closed vessel during combustion. Results of both video and pressure trace analyses show a linear relationship between turbulent burning velocity and turbulence intensity as expected. Moderate changes in equivalence ratio had a negligible effect on this relationship.