Soot formation in a turbulent swirling flow

The qualitative understanding of soot formation in simple models of gas turbine primary-zone combustors is summarized. Soot formation in flame radiation and air pollution was investigated. Results are presented, namely: (1) if the fuel is premixed with air in approximately stoichiometric proportions, the sequence of states that a fluid element undergoes as it burns is quite different from the sequence when liquid or vapor fuel is injected into an air-flow; (2) swirling flows, as are typical or swirl-can combustors, when burning, can amplify small aerodynamic disturbances upstream of the swirl vanes; and (3) different fuels form significantly different amounts of soot. Each of these effects makes major changes in the amount of soot formed in a given combustor

Euler-Lagrange relationship for random dispersive waves Scientific report

Euler-Lagrange relationship for random dispersive wave

Euler-Lagrange relationship for random dispersive waves

Euler-Lagrange relationship for random dispersive wave

Wake of the Moon

Lunar wak

Laboratory measurements in a turbulent, swirling flow

Measurements of soot inside a flame-tube burner using a special water-flushed probe are discussed. The soot is measured at a series of points at each burner, and upon occasion gaseous constitutents NO, CO, hydrocarbons, etc., were also measured. Four geometries of flame-tube burners were studied, as well as a variety of different fuels. The role of upstream geometry on the downstream pollutant formation was studied. It was found that the amount of soot formed in particularly sensitive to how aerodynamically clean the configuration of the burner is upstream of the injector swirl vanes. The effect of pressure on soot formation was also studied. It was found that beyond a certain Reynolds number, the peak amount of soot formed in the burner is constant

Flexural fatigue performance of CFRP prestressed concrete poles

Carbon fibre reinforced polymer (CFRP) prestressed concrete poles offer a durable, light-weight alternative to conventional steel-reinforced or prestressed concrete poles. In particular, the corrosion resistance of the CFRP tendons can result in lower maintenance costs and a reduction in the required concrete cover. For lighting poles used in pedestrian or low-trafficked areas, wind loading represents a dominant load case. The wind acts as a transient force and can blow from any direction. It is therefore of interest to investigate how CFRP prestressed lighting poles perform under repeated cyclic loads and/or load reversals. Experiments were carried out on pole sections tested horizontally. These included a static control test and a conventional fatigue test where a cyclic load was applied in a downwards direction for 2 million cycles. Three further fatigue tests where the load direction changed, either after a defined number of cycles or within a load cycle, were also conducted. It was found that all the poles performed adequately for 1–2 million cycles of loading and that the majority of any deflection increases occurred within the first 50,000 cycles. It is believed that repeated cyclic loading may have increased the tendon debonding at the crack locations. Localised debonding potentially relieves the stress in the outermost tendon layer which delays the onset of failure and allows the inner tendon layers to take up further stress thus leading to a higher load carrying capacity. Loading orientation reversal from a downwards to an upwards direction within a loading cycle did not result in a greater stiffness degradation when compared to the other fatigue tests. The initial findings suggest that in-service cyclic loading and load reversals will not be detrimental to the performance of CFRP prestressed concrete poles. This is the accepted version of an original publication available here: http://multi-science.metapress.com/content/w842084116q73104/?genre=article&id=doi%3a10.1260%2f1369-4332.15.4.57

Methods of Integrating Design and Cost Information to Achieve Enhanced Manufacturing Cost/Performance Trade-offs

In this paper we address problems which arise when large organizations attempt a tight integration of design and cost while developing complex products. Topics include the sources of cost and design data, the arrangement of the databases, and the interfaces required. We also discuss the management methods required to develop and implement Design/Cost Database Commonality