Two-Dimensional Numerical Investigation of a Micro Combustor


Department of Mechanical Engineering,Sharif University of Technology


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 coecient 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 coecient 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 coecient 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.