Characteristics of liquid fuel combustion in a novel miniature vortex combustor

Abstract

Miniature liquid fuel combustor in power generation requires confining combustion in the combustor chamber. However, this process faces substantial challenges that include higher heat loss, poor fuel vaporization rate, and low mixing residence time. In response to this challenge, a new method is proposed by introducing novel miniature combustor utilizing the advantage of the vortex flow motion that consists of two parts, a double chamber (inner tube and outer tube) at the top and a vortex-trapped chamber that is attached to anchor the flame at the bottom. The present combustor was operated by using n-heptane liquid fuel at fuel flow rate of 1.0–2.5 mL min−1 and airflow rate of 7.0–20.0 L min−1. The results showed that the heat transfer and recirculation mechanism sustain the combustion in the combustion chamber at fuel-lean regime. Confinement of the combustion inside the combustion chamber is attributed to recirculation phenomenon that was demonstrated through the enhancement of residence time and mixing rate. It is observed that the annulus enhanced the fuel vaporization rate, which is verified by measuring the temperature distribution at the combustor surfaces. The results of the thermal analysis also showed that the heat transfer enhancement is attributed to the vortex flow motion.