Search

There is growing interest in combustion-driven thermophotovolataic (TPV) power generation. Previous investigations have shown that inadequate conversion of fuel energy to photon-convertible radiation restrained combustion-driven TPV power systems from achieving high efficiency. In this paper, A TPV power system integrating a composite radiant burner and cells with different low bandgaps was proposed and constructed. The composite radiant burner consists of two thermal radiators in tandem. They emit two streams of radiation. GaSb cells and InGaAsSb cells were installed in the TPV power system, and were illuminated by the two radiators, respectively. The radiations were matched correspondingly to the sensitivities of GaSb and InGaAsSb cells. The combustion performance of the composite radiant burner and the electric output characteristics of the TPV cells in the integrated natural gas-fired TPV system were investigated under various conditions. The proposed cascaded utilization of heat released during the combustion and the effective thermal management successfully increased the TPV system efficiency. [ABSTRACT FROM AUTHOR]

This paper investigates the geometric parameters related to thermal efficiency and pollution emission of a multi-hole flat flame burner. Recent experimental studies indicate that such burners are significantly influenced by both the use of distribution mesh and the size of the diameter of the main and retention holes. The present study numerically simulated methane-air premixed combustion using a two-step mechanism and constant mass diffusivity for all species. The results indicate that the addition of distribution mesh leads to uniform flow and maximum temperature that will reduce NOx emissions. An increase in the diameter of the main holes increased the mass flow which increased the temperature, thermal efficiency and NOx emissions. The size of the retention holes should be considered to decrease the total flow velocity and bring the flame closer to the burner surface, although a diameter change did not considerably improve temperature and thermal efficiency. Ultimately, under temperature and pollutant emission constraints, the optimum diameters of the main and retention holes were determined to be 5 and 1.25 mm, respectively. [ABSTRACT FROM AUTHOR]

In this paper we report an experimental investigation of the dynamical features of a propagating partially premixed flame established on a concentric coflow burner. The variation regulation about the propagation and structure characteristics in different inflow condition is analyzed basing on high-speed photography. The results show that 1)In condition of large center jet velocity, transition from turbulent to laminar combustion is exhibited in the process of attaching, reverse transition is observed in the process of blowing out. 2)A stronger rich-premixed center flow mainly enhances the flame propagation in an attaching flame and the local flow velocity in a blowing out flame. 3)The displacement of the flame base and tip accounts for the major change and small-scale oscillation in the flame length, respectively. 4)The flicker of the flame slacks when the propagation state transitions to lifted-off or blowing out from attaching. [ABSTRACT FROM AUTHOR]