The usual boundary conditions used at the solid-nanofluid interface are no slip velocity for flow and no-flux for nano-particle. For thermal boundary condition (which depicts heat transfer) if we know the temperature at the wall, we use the temperature boundary condition, otherwise, if we know the heat generation in the solid wall we can use the heat flux boundary condition. For that case the flux at the boundary will be the flux at the wall as
q= -k_nf \grad T . n,
where k_nf is the thermal conductivity of nanofluid, which increases with the increase in volume fraction. Please remember your viscosity is also getting increased with an increase in volume fraction. The increase of viscosity can decrease the strength of flow (modified Reynolds number) for which the effect of convective heat transfer can decrease. You may refer to the following paper for the boundary condition details.
https://asmedigitalcollection.asme.org/manufacturingscience/article/139/11/114501/383987
This paper considers only isothermal boundary condition and considers only low volume fraction.
The usual boundary conditions used at the solid-nanofluid interface are no slip velocity for flow and no-flux for nano-particle. For thermal boundary condition (which depicts heat transfer) if we know the temperature at the wall, we use the temperature boundary condition, otherwise, if we know the heat generation in the solid wall we can use the heat flux boundary condition. For that case the flux at the boundary will be the flux at the wall as
q= -k_nf \grad T . n,
where k_nf is the thermal conductivity of nanofluid, which increases with the increase in volume fraction. Please remember your viscosity is also getting increased with an increase in volume fraction. The increase of viscosity can decrease the strength of flow (modified Reynolds number) for which the effect of convective heat transfer can decrease. You may refer to the following paper for the boundary condition details.
https://asmedigitalcollection.asme.org/manufacturingscience/article/139/11/114501/383987
This paper considers only isothermal boundary condition and considers only low volume fraction.
depends upon the density of nanoparticle used in the system, there may be chance to get particle settlement, which will reduce the quantity of flowing nanoparticles in the the flowing fluid, ultimately will reduce the heat transfer rate.
It depends on the thermal conductivity of the nanoparticles used (if it high it will increase, low it will decrease)
- Badges
- Science topic
- Similar topics
- Engineering
- Thermal Engineering
- Thermofluid
- Heat Transfer