Multiple jets injected radially into a reactive and a non-reactive cross-flow in a cylindrical chamber has been studied numerically using FLUENT CFD code. The chamber diameter was varied from 0.3 m to 3 m and the number of nozzles from 8 to 32. The maximum temperature difference over the chamber's cross-sectional area was defined as the parameter to evaluate the mixing quality. The optimum mixing conditions for both reactive and nonreactive flows were obtained at a normalized momentum flux ratio (J/n 2 ) of 0.3 with a penetration depth (h/R) of 0.6. This condition is valid for all number of nozzles. However, increasing the number of nozzles will also improve the mixing quality. It has been observed that for higher number of nozzles, the optimum mixing quality is nearly independent of J/n 2 in the range greater than 0.3. This is important for the processes with ever-changing conditions which is typical in chemical processing industry.

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Multiple rows of jets injected into a cross flow with diameters of 0.3 to 3 m were studied experimentally and numerically. The measured values were in good agreement with CFD calculations. The optimum mixing for a single row was obtained at a normalized momentum flux ratio (J/n 2 ) of 0.3 with a penetration depth (h/R) of 0.6, which is in accordance with previous studies. This condition is valid for all numbers of nozzles. However, increasing the number of nozzles will also improve the mixing quality. Double rows with a staggered arrangement always give a worse mixing quality, compared to a single row. Double rows with an inline arrangement will improve the mixing quality only if the injected volumetric flows produce over-and under-penetrated jets for a V : jo1 /V : jo2 ratio of 3/1 or 1/3. For operation under ever changing conditions a single row with J/n 2 > 0.3 and n ≥ 24 is recommended.