TY - JOUR
T1 - The low Reynolds number turbulent flow and mixing in a confined impinging jet reactor
AU - Schwertfirm, Florian
AU - Gradl, Johannes
AU - Schwarzer, Hans C.
AU - Peukert, Wolfgang
AU - Manhart, Michael
PY - 2007/12
Y1 - 2007/12
N2 - Turbulent mixing takes an important role in chemical engineering, especially when the chemical reaction is fast compared to the mixing time. In this context a detailed knowledge of the flow field, the distribution of turbulent kinetic energy (TKE) and its dissipation rate is important, as these quantities are used for many mixing models. For this reason we conduct a direct numerical simulation (DNS) of a confined impinging jet reactor (CIJR) at Re = 500 and Sc = 1. The data is compared with particle image velocimetry (PIV) measurements and the basic flow features match between simulation and experiment. The DNS data is analysed and it is shown that the flow is dominated by a stable vortex in the main mixing duct. High intensities of turbulent kinetic energy and dissipation are found in the impingement zone which decrease rapidly towards the exit of the CIJR. In the whole CIJR the turbulence is not in equilibrium. The strong mixing in the impingement zone leads to a rapid development of a monomodal PDF. Due to the special properties of the flow field, a bimodal PDF is generated in cross-sections downstream the impingement zone, that slowly relaxes under relaminarising conditions. The time required for meso-mixing is dominating the overall mixing performance.
AB - Turbulent mixing takes an important role in chemical engineering, especially when the chemical reaction is fast compared to the mixing time. In this context a detailed knowledge of the flow field, the distribution of turbulent kinetic energy (TKE) and its dissipation rate is important, as these quantities are used for many mixing models. For this reason we conduct a direct numerical simulation (DNS) of a confined impinging jet reactor (CIJR) at Re = 500 and Sc = 1. The data is compared with particle image velocimetry (PIV) measurements and the basic flow features match between simulation and experiment. The DNS data is analysed and it is shown that the flow is dominated by a stable vortex in the main mixing duct. High intensities of turbulent kinetic energy and dissipation are found in the impingement zone which decrease rapidly towards the exit of the CIJR. In the whole CIJR the turbulence is not in equilibrium. The strong mixing in the impingement zone leads to a rapid development of a monomodal PDF. Due to the special properties of the flow field, a bimodal PDF is generated in cross-sections downstream the impingement zone, that slowly relaxes under relaminarising conditions. The time required for meso-mixing is dominating the overall mixing performance.
KW - Confined impinging jet reactor
KW - Direct numerical simulation
KW - Opposing jets
KW - Particle image velocimetry
KW - Turbulent mixing
UR - http://www.scopus.com/inward/record.url?scp=36248932233&partnerID=8YFLogxK
U2 - 10.1016/j.ijheatfluidflow.2007.04.019
DO - 10.1016/j.ijheatfluidflow.2007.04.019
M3 - Article
AN - SCOPUS:36248932233
SN - 0142-727X
VL - 28
SP - 1429
EP - 1442
JO - International Journal of Heat and Fluid Flow
JF - International Journal of Heat and Fluid Flow
IS - 6
ER -