No abstract

No abstract

This paper presents a joint experimental and numerical study on premixed laminar ammonia/methane/air flames, aiming to characterize the flame structures and NO formation and determine the laminar flame speed under different pressure, equivalence ratio, and ammonia fraction in the fuel. The experiments were carried out in a lab-scale pressurized vessel with a Bunsen burner installed with a concentric co-flow of air. Measurements of NH and NO distributions in the flames were made using planar laser-induced fluorescence. A novel method was presented for determination of the laminar flame speed from Bunsen-burner flame measurements, which takes into account the non-uniform flow in the unburned mixture and local flame stretch. NH profiles were chosen as flame front markers. Direct numerical simulation of the flames and one-dimensional chemical kinetic modeling were performed to enhance the understanding of flame structures and evaluate three chemical kinetic mechanisms recently reported in the literature. The stoichiometric and fuel-rich flames exhibit a dual-flame structure, with an inner premixed flame and an outer diffusion flame. The two flames interact, which affects the NO emissions. The impact of the diffusion flame on the laminar flame speed of the inner premixed flame is however minor. At elevated pressures or higher ammonia/methane ratios, the emission of NO is suppressed as a result of the reduced radical mass fraction and promoted NO reduction reactions. It is found that the laminar flame speed measured in the present experiments can be captured by the investigated mechanisms, but quantitative predictions of the NO distribution require further model development.

An exploratory study was conducted to evaluate the properties of laminated-bamboo lumber, herein referred to as LBL. Quasi-flattened Moso bamboo (Phyllostachys pubescens) were laminated using a resorcinol-based adhesive to form a composite which is similar in construction to that of laminated-veneer lumber (LVL). Representative samples were tested for static bending properties, internal bond strength, and dimensional stability. The effect of initial moisture content (10 and 15 percent) and glue spread rate (220, 320 and 420g/m 2 single glueline) on LBL properties was also analyzed. Results indicate that LBL exhibits superior strength property compared to wood-based LVL, as indicated by its higher MOR. Its MOE, however, was slightly lower. Initial MC (within 15 percent) did not have a significant effect on the mechanical properties of LBL, but it appears to have a significant effect on dimensional stability. Glue spread rate had a significant effect on both the mechanical and physical properties.

No abstract

No abstract

No abstract

No abstract