Two-Dimensional Numerical Investigation of a Micro Combustor

Abstract

In this paper, a two-dimensional numerical approach is used to study the e ect of micro combustor height, mass ow rate and external convection heat transfer coe cient on the temperature and species mass fraction pro les. A premixed mixture of H2-Air with a multi-step chemistry is used. The transient gas phase energy and species conservation equations result in an Advection-Di usion-Reaction system that leads to two sti systems of PDEs. In the present work, the computational domain is solved through the Strang splitting method, which is suitable for a nonlinear sti system of PDEs. A revised boundary condition for the velocity equation is applied and its e ect on the ow characteristics is investigated. The results show that both convection heat transfer coe cient and micro combustor height have a signi cant e ect on the combustion and heat transfer rates in the micro scales. Also increasing the convective heat transfer coe cient and decreasing the height and inlet mixture velocity, decreases temperature and active radicals along the micro combustor. In addition, the slip ow and thermal creep boundary conditions in the studied scales have no signi cant e ect on the di erent parameters, but changes slightly the cross section pro les of the temperature. The 2-D numerical results show that the micro combustion must be treated as two dimensional.