what should be reynolds no for oil used in cooling the mold?

[madhukeshwart]

what should be reynolds number for oil used in cooling the mold?

Is 10000 is required or not for oil ?

If required flow rate of coolant will be very high, which is not practical or required
power to pump that flow rate is very high ?

Can anyone answer my question, if any body used oil and simulated the same
with moldflow ?

[iboothy]

I believe that the Reynolds number should remain 10000 no matter what the cooling medium used. Terbulent flow should occur at the same Reynolds number whether it be oil or water, and terbulent flow is what is required for efficient heat transfer from the mould to the coolant.


Re = (ρVd) / µ

where:
V is the mean fluid velocity (SI units: m/s)
D is the diameter (m)
μ is the dynamic viscosity of the fluid (Pa·s or N·s/m²)
ρ is the density of the fluid (kg/m³)

Hope this helps.


EDIT:
I'm not sure of the ρ and μ of water and oil, but if these are set then you could increase the diameter of the cooling circuit, which will enable you to decrease the velocity (or flow rate) of the oil to achieve the same Re. if you know the ratio of the flow rate between oil and water at Re = 10000, then you can modify the circuit diameter in the same ratio to achieve Re = 10000 for oil for the same flow rate as water.

Edited by: iboothy on Aug 4, 2009 10:41 AM Edited by: iboothy on Aug 4, 2009 10:46 AM

[StephaneCorduan1456]

Oil should be use to heat mold the mold and not to cool down.
And so the Re has not to be considered.

[madhukeshwart]

I feel Mr .Stephane is right

[tupperdude]

'Oil should be use to heat mold the mold and not to cool down.

And so the Re has not to be considered.'




Sorry, I disagree with you there Stephane, plastic melt for oil cooled moulds is around 300°C plus. therefore if the mould is at 150°C it is still cooling the plastic.

Yes I agree you are heating the mould from ambient temperature.



Cheers

Danny