TY - JOUR
T1 - Numerical investigation on buoyancy and inclination effects on transient mixed convection in a channel with discretely heated plane symmetric contraction-expansions
AU - García, F.
AU - Treviño, C.
AU - Salcedo, E.
AU - Martínez-Suástegui, L.
N1 - Publisher Copyright:
© 2019 Elsevier Masson SAS
PY - 2019/12
Y1 - 2019/12
N2 - In this work, transient mixed convection in a channel with discretely heated plane symmetric contraction-expansions at the mid-channel section emulating electronic components is studied numerically. The facing walls of the obstructions are isothermal, the other bounding walls of the constriction and the channel have non-adiabatic walls. The impact of changes in the cross section and their corresponding sensitivity to duct orientation on the overall flow and thermal evolution in space and time is analysed for fixed Prandtl number of Pr=7, Reynolds number in the range 100 ≤Re≤ 1000, channel inclination of 0∘≤Γ≤90∘, and different values of buoyancy strength (Richardson number). Results indicate that as the duct approaches the horizontal configuration, buoyancy strength reduces and higher threshold values of the Richardson number are required to induce instability. Also, depending on the parametric set, the flow and temperature distributions can experience an oscillatory behavior associated to variations in size of a complex vortical structure that occupies the spatial region near the partial blockage and that extends to downstream positions of the latter. Numerical predictions demonstrate how the blockage height affects the wake structure and vortex dynamics, and the effects of the Prandtl number and heat losses to the channel walls on the evolution of the flow and heat transfer response are presented and discussed in detail.
AB - In this work, transient mixed convection in a channel with discretely heated plane symmetric contraction-expansions at the mid-channel section emulating electronic components is studied numerically. The facing walls of the obstructions are isothermal, the other bounding walls of the constriction and the channel have non-adiabatic walls. The impact of changes in the cross section and their corresponding sensitivity to duct orientation on the overall flow and thermal evolution in space and time is analysed for fixed Prandtl number of Pr=7, Reynolds number in the range 100 ≤Re≤ 1000, channel inclination of 0∘≤Γ≤90∘, and different values of buoyancy strength (Richardson number). Results indicate that as the duct approaches the horizontal configuration, buoyancy strength reduces and higher threshold values of the Richardson number are required to induce instability. Also, depending on the parametric set, the flow and temperature distributions can experience an oscillatory behavior associated to variations in size of a complex vortical structure that occupies the spatial region near the partial blockage and that extends to downstream positions of the latter. Numerical predictions demonstrate how the blockage height affects the wake structure and vortex dynamics, and the effects of the Prandtl number and heat losses to the channel walls on the evolution of the flow and heat transfer response are presented and discussed in detail.
KW - Forward-backward facing step
KW - Mixed convection
KW - Oscillatory fluid motion
KW - Partially blocked geometries
KW - Separation and reattachment flow
KW - Wall effects
UR - http://www.scopus.com/inward/record.url?scp=85071249575&partnerID=8YFLogxK
U2 - 10.1016/j.ijthermalsci.2019.106056
DO - 10.1016/j.ijthermalsci.2019.106056
M3 - Artículo
AN - SCOPUS:85071249575
SN - 1290-0729
VL - 146
JO - International Journal of Thermal Sciences
JF - International Journal of Thermal Sciences
M1 - 106056
ER -