Performance characteristics of a thin‐layered radial porous burner with different strategies for fuel‐air mixture supply

Abstract

A recent surge of interest is focused on developing radiant burners that may replace traditional open flame burners because of their ability to interchangeably use a wide range of fuels with improved emissions and the overall efficiency of combustion appliances. This research focuses on identifying conditions under which a radiant burner with a thin‐layered radial porous emitter operates in the internal combustion mode with increased radiation efficiency alongside decreased noise and NOx emission. The way the fresh mixture distributes over the cylindrical cavity of the emitter is the main factor affecting the burner performance. Two strategies for fuel‐air mixture supply were considered: (i) co-axial feed of turbulent flow through the open end of the cylindrical emitter using a divergent annular nozzle; (ii) distributed radial feed of laminar flow through a thin‐layered conical porous insert located inside the cavity of the emitter. The burner performance (radiation efficiency, NOX, and noise emissions) was experimentally studied in the ranges of thermal power of 4.0–9.1 kW and equivalence ratio of 0.5–1.0, which corresponds to the range of the emitter temperature from 500 to 1190 K. It was established that the distributed radial feed of fresh mixture dramatically reduced the noise emission, markedly improved the uniformity of the emitter temperature, and slightly increased the radiation efficiency of the burner. The improved combustion performance makes the thin‐layered radial porous burners relevant for application in domestic heating appliances.