Performance optimization design of trapped vortex combustion chamber with a sand dune blunt body

Abstract

In an effort to enhance the performance of the trapped vortex combustion chamber, this paper improved the trapped vortex combustion chamber and proposed a sand dune trapped vortex combustion chamber. Firstly, the effects of different inlet velocities and equivalence ratios on the performance of the two combustion chambers were analyzed. The results showed that under the same operating conditions, the performance of the sand dune trapped vortex combustion chamber was better than that of the trapped vortex combustion chamber. Then, a central composite design (CCD) response surface experimental method was adopted to optimize the structure of the sand dune trapped vortex combustion chamber in detail. The windward angle (α), leeward angle (θ), and rear blunt body height (h) were used as influencing factors. The combustion efficiency (η), pressure loss (δ*), and NOx emissions were used as response variables. Quadratic polynomial regression equations for η, δ*, and NOx emissions were established respectively. Subsequent to this, the expected value function method was employed for multi-objective optimization of the three regression equations. After optimization, compared with the original trapped vortex combustion chamber, the combustion efficiency of the sand dune trapped vortex combustion chamber increased from 87.56 % to 95.41 %, NOx emissions decreased from 747.94 ppm to 386.35 ppm, the outlet temperature distribution factor (OTDF) decreased from 0.21 to 0.07, and field synergy β diminished from 83.11 to 76.60. Although the pressure loss increased from 2.30 % to 3.50 %, this is within an acceptable range.