ABSTRACT
Combined convection heat transfer and thermal conduction for film cooling of a flat plate with 45° ribs on one wall was investigated experimentally and numerically. The flat plate surface temperature was measured using thermochromic liquid crystals. The results show that the film cooling is the main mechanism for the local cooling with a very low thermal conductivity while the convection heat transfer of the coolant in the coolant channel is the dominant heat transfer mechanism for the high thermal conductivity plate, with both film cooling and convection heat transfer by the coolant being important with medium thermal conductivity walls.
Nomenclature
l | = | plate length, m |
p | = | Pressure, Pa |
Pr | = | Prandtl number |
Re | = | Reynolds number based on the plate channel hydraulic diameter |
T | = | temperature, ℃ |
ui | = | velocity components, m/s |
x,y,z | = | coordinates, m |
Greek symbols
ε | = | dissipation of turbulent kinetic energy, m2/s3 |
η | = | cooling effectiveness |
k | = | turbulence kinetic energy, m2/s2 |
λ | = | thermal conductivity, W/(m·K) |
μ | = | dynamic viscosity, Pa⋅s |
μt | = | turbulent dynamic viscosity, Pa⋅s |
ρ | = | density, kg/m3 |
ω | = | specific dissipation, 1/s |
Subscripts
c | = | coolant |
h | = | hot air |
l | = | local |
w | = | wall |
wl | = | local wall |
x,y,z | = | coordinate direction |
Acknowledgment
We thank Prof. David Christopher for editing the English.
Funding
This project was supported by the National Natural Science Foundation of China (No. 51306099) and the Science Fund for Creative Research Groups of the NSFC (No. 51321002).