Heat transfer in the chemically reacting N2O4 gas laminar flow in triangular bundles of rods

The problems of heat and mass transfer in a laminar flow of chemically reacting N2O4 reversible 2NO2 reversible 2NO + O2 coolant along a rod bundle are considered. Temperature and concentration fields are obtained using a numerical solution of the differential set of energy and mass conservation equations by the method of variable directions with allowance for the initial section. It has been supposed in this case that ''frozen'' thermodynamic and transfer properties do not depend on temperature, the flow is hydrodynamically stabilized, the temperature and concentration of the mixture components at the channel inlet are constant over the cross-section. When heated, nitrogen tetroxide decomposes sequentially in two stages, the first one may be considered as equilibrium, and the second proceeds with a final velocity. To describe heat exchange in the first reaction stage the fact is used, that the energy equation with Le=1 coincides with the energy equation for the frozen flow, and the enthalpy field is unambiguously related to the temperature field at chemical equilibrium. In considering the second reaction stage a numerical solution of the set of differential equations has been obtained for the following parameters: t=1.05; 1.1; 1.3; Le=0.5; 1; 1.5 under the boundary conditions of the first and second orders. The temperature fields in the initial section in laminar flow of chemically inert substances are obtained. The stabilized Nusselt numbers found are in a good agreement with previous data. A substantial effect of the chemical reaction both on heat transfer and temperature non-uniformity of the rod surface over a perimeter is also shown