Research Of Flame Stabilization And Combustion Intensification In A Novel Combustor With Slotted Swirler

As one of the key components of swirl combustor, swirler plays an important roleon flame stabilization and combustion intensification of the combustor. In swirlcombustor, oncoming air flow is rotated and divided into radial, axial and tangentialcomponents by swirler. Due to the air viscosity, gas in the center of chamber is taken intomain flow by the rotating and expanding oncoming air, results in a rarefied air and lowpressure region in the center of chamber, thereby backflow is generated due to theadverse pressure gradient in chamber. This region is called as center recirculation zone(CRZ), in which high temperature post-combustion flue gas is returned to preheat initialfuel flow, introduce earlier ignition and thus enhance combustion and improve flamestability.In present work, a novel combustor with slotted swirler (CSS) is researched. Themain idea is to cut6slits (central straight-flow holes) on the swirler for delivering smallamount of fuel and air directly into the center recirculation zone to ignite it in the mostadvantageous environment to form a pilot flame, which provides a sufficient heat sourcefor dependable ignition and steady combustion. Velocity was measured to analyze theflow pattern, temperature measurement values and composition of combustion productswere obtained to research flame characteristics and combustion efficiency both inexperimental rigs of a CSS and a traditional swirl combustor (TSC). Numericalsimulation of non-reacting flow and kerosene droplet non-premixed combustion wasperformed with three-dimensional (360°) mathematical models to validate theexperimental results. The experimental and numerical results show that, owning to theslits, a high temperature and permanent flame is produced in CSS, which is always onduty behind the swirler, thereby the stability characteristics of the combustor wereoptimized; the distribution of fuel and air is more reasonable and flue-air mixing is moreintense, so that combustion is enhanced. The on-coming airflow from the slits decrease negative pressure in the combustor, results in a lower pressure loss. Combustion isconcentrated in the center of combustor, as a result, the chamber-wall temperature in CSSis lower than that in a non-slotted one， thereby the life-span of the combustor isprolonged. What’s more, the mechanism of flame stabilization and combustionintensification in CSS was researched.