Numerical investigation on temperature fluctuation of the parallel triple-jet

Temperature fluctuation is caused by the mixing flows out of the core with different temperature in upper plenum. The phenomenon may lead to thermal fatigue in solid structures. In this paper, the parallel triple-jet flows were simulated by the software FLUENT with the large eddy simulation (LES). By comparison, the numerical results were in good agreement with the experimental ones. The flow field observed in simulation showed that many vortices are closely related with the temperature fluctuation phenomenon. From the computed results, it was discovered that amplitudes of temperature fluctuation are different in flow field, while the frequency of temperature fluctuation remains constant at all monitoring position. With the increasing of Reynolds number, the mixing of hot and cold flows is delayed, and convective mixing region is enlarged.