A Three Dimensional CFD Simulation of

Detemmerman and Froment [1998] carried out a three dimensional coupled CFD simulation of furnaces and reactor tubes for the millisecond thermal cracking of propane into ethylene in the presence of steam, a process already discussed in Chapters 1 and 9. 

The coupled furnace-reactor simulation requires an accurate description of the heat transfer from the furnace to the reactor. The global radiative heat transfer from the furnace to the reactor was calculated by the zone method (Fig. 12.5.A-2, Left) proposed by Hottel and Sarofim [1967], To take into account the local influence of radiative heat transfer, CFD simulations of the furnace were carried out using a radiative heat transfer model for short distances [De Marco and Lockwood, 1975], Knowledge of the local flue gas composition is required to calculate the heat release by combustion in each flue gas volume element and the absorption coefficients for radiation. Coupled CFD simulations of the reactor tubes and furnace predict the process gas conversion and the product yields, as well as coke formation rates. 

For the calculation of the global radiative heat transfer from the furnace to the reactor, the former is divided into isothermal surface and volume zones (Fig. 12.5.A-2). Because of the symmetry, only one fourth of the furnace has to 

Furnace volume element for the flow pattern calculations 

Side and top view of a thermal cracking furnace with straight parallel reactor tubes. 

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Example 12.5.A Three Dimensional CFD Simulation of Furnace and Reactor Tubes for the Thermal Cracking of Hydrocarbons... 

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