ABSTRACT
In this study, fluid flow and heat transfer in a trapezoidal microchannel are numerically investigated. For this purpose, a reference study with experimental and numerical solutions is adopted from the literature and solved with COMSOL multiphysics. Good agreement with the results of the reference work is obtained. In addition, effects of stabilization methods and element discretization options that are offered by the program on the results are investigated and discussed with examples. In addition, two different versions of the same program are compared on the effect of stabilization methods on results. Last, some comments on the level of relative tolerance are provided.
Nomenclature
Ac | = | cross-sectional area (m2) |
Cp | = | specific heat of the fluid (J/kg K) |
Dh | = | hydraulic diameter (m) |
f | = | friction constant |
G | = | mass flux (kg/m2 s) |
H | = | height of microchannel (m) |
k | = | thermal conductivity of the fluid (W/m K) |
L | = | length of the microchannel (m) |
Nu | = | Nusselt number, Nu = qDh/(kΔT) |
p | = | pressure (Pa) |
qeff | = | effective heat flux (kW/m2) |
Re | = | Reynolds number, Re = ρUDh/μ |
T | = | temperature (K) |
= | velocity field | |
w | = | z-component of the velocity (m/s) |
Wb | = | base width of microchannel (m) |
Wt | = | top width of microchannel (m) |
Greek symbols | ||
µ | = | Dynamic viscosity (Pa s) |
ρ | = | density of the fluid (kg/m3) |
θ | = | side angle of the microchannel |
Subscripts | ||
HS | = | heated surface |
Po | = | Poiseuille number, Po = fRe |
Γ | = | boundary |
m | = | mean |
max | = | maximum |
w | = | wall |
z | = | z-direction |
Nomenclature
Ac | = | cross-sectional area (m2) |
Cp | = | specific heat of the fluid (J/kg K) |
Dh | = | hydraulic diameter (m) |
f | = | friction constant |
G | = | mass flux (kg/m2 s) |
H | = | height of microchannel (m) |
k | = | thermal conductivity of the fluid (W/m K) |
L | = | length of the microchannel (m) |
Nu | = | Nusselt number, Nu = qDh/(kΔT) |
p | = | pressure (Pa) |
qeff | = | effective heat flux (kW/m2) |
Re | = | Reynolds number, Re = ρUDh/μ |
T | = | temperature (K) |
= | velocity field | |
w | = | z-component of the velocity (m/s) |
Wb | = | base width of microchannel (m) |
Wt | = | top width of microchannel (m) |
Greek symbols | ||
µ | = | Dynamic viscosity (Pa s) |
ρ | = | density of the fluid (kg/m3) |
θ | = | side angle of the microchannel |
Subscripts | ||
HS | = | heated surface |
Po | = | Poiseuille number, Po = fRe |
Γ | = | boundary |
m | = | mean |
max | = | maximum |
w | = | wall |
z | = | z-direction |