ABSTRACT
The efficiency of plate heat exchangers (PHE) is extremely influenced by the various flowing conditions and heat transfer caused by the complex structure. Numerical simulation of PHE with low flux and high heat transfer was performed using Computational Fluid Dynamics (CFD). To prove that the simulation result was reliable, an experimental system based on the principle of equal velocity method was set up. Furthermore, the criterion equations of hot and cold fluid were derived. The heat transfer coefficient and flow resistance under various Reynolds numbers were analyzed and validated by experiment. Finally, we found that the realizable k-ε offered the best results.
Nomenclature
As | = | cross-section area of the flow channel |
b | = | average distance between two plates |
d | = | the equivalent diameter |
h | = | plate height |
I | = | turbulence intensity |
k | = | turbulent energy |
K | = | overall coefficient of heat transfer |
L | = | the characteristic length |
Nu | = | Nusselt number |
Pr | = | Prandtl number |
Pout | = | outlet pressure of the pump |
Re | = | Reynolds number |
S | = | wetted perimeter |
Tc,in | = | inlet temperature of the cold side |
Tc,out | = | outlet temperature of the cold side |
Th,in | = | inlet temperature of the hot side |
Th,out | = | outlet temperature of the hot side |
uavg | = | average velocity of the fluid |
uw | = | velocity of the fluid |
α | = | heat transfer coefficient |
δ | = | thickness of the plate |
Δp | = | difference between actual values and computation values |
λw | = | thermal conductivity |
υ | = | kinematic viscosity |
Subscripts | = | |
1 | = | hot fluid |
2 | = | cold fluid |
avg | = | average value |
c | = | cold side |
h | = | hot side |
in | = | inlet |
out | = | outlet |
w | = | water |
Nomenclature
As | = | cross-section area of the flow channel |
b | = | average distance between two plates |
d | = | the equivalent diameter |
h | = | plate height |
I | = | turbulence intensity |
k | = | turbulent energy |
K | = | overall coefficient of heat transfer |
L | = | the characteristic length |
Nu | = | Nusselt number |
Pr | = | Prandtl number |
Pout | = | outlet pressure of the pump |
Re | = | Reynolds number |
S | = | wetted perimeter |
Tc,in | = | inlet temperature of the cold side |
Tc,out | = | outlet temperature of the cold side |
Th,in | = | inlet temperature of the hot side |
Th,out | = | outlet temperature of the hot side |
uavg | = | average velocity of the fluid |
uw | = | velocity of the fluid |
α | = | heat transfer coefficient |
δ | = | thickness of the plate |
Δp | = | difference between actual values and computation values |
λw | = | thermal conductivity |
υ | = | kinematic viscosity |
Subscripts | = | |
1 | = | hot fluid |
2 | = | cold fluid |
avg | = | average value |
c | = | cold side |
h | = | hot side |
in | = | inlet |
out | = | outlet |
w | = | water |
Acknowledgments
This work was supported in part by the National Natural Science Foundation of China (51276118).