Germination

Materials science

Physics

Impeller

Botany

Large eddy simulation

Flow (mathematics)

Quantum mechanics

Meteorology

Stratification (seeds)

Mechanics

Biology

Thermal

Thermodynamics

Jet (fluid)

Temperature gradient

Mixing (physics)

Turbulence

Dormancy

Seed dormancy

Applied Thermal Engineering

Thermal stratification is the main reason for thermal fatigue failure in the rectangular T-junction. An impeller is set in the mixing zone in the rectangular T-junction to improve the mixing behaviour of hot and cold fluids under the deflecting jet with the inflow momentum ratio of MR = 0.49. Blade numbers and blade diameters are investigated for the range of Np = 2 ∼ 4 and Dp* = 0.33 ∼ 0.8, respectively. By the application of large-eddy simulation, the flow fields and temperature fields are obtained in this work. The flow fields show the mixing behaviour between hot and cold fluids can be promoted by setting the impeller with a constant rotation speed, and three flow patterns including the wall jet, deflecting jet and impinging jet will be observed in the T-junction, which is effective for breaking the thermal stratification. Temperature fluctuation and temperature gradient calculated by mean temperature are compared with that of no impeller. It is found that by adding the impeller the temperature gradient i...

Numerical simulation of the mixing behaviour of hot and cold fluids in the rectangular T-junction with/without an impeller