Cooling circuit Reynolds number for RTM (transient from start-up) result

The Cooling circuit Reynolds number for RTM (transient from start-up) result shows the Reynolds number of the coolant flow in the cooling circuit. It is a time dependant result, from the beginning of the first mold preheating stage.

Using this result

Turbulent flow is preferred for effective heat transfer. However, the higher the Reynolds number in the circuit, the more energy is required from the pump. The ideal Reynolds number for heat transfer is 10,000. The pumping losses associated with Reynolds higher than 10,000 outweigh the heat transfer efficiency gains.

Increasing the length or number of the circuits improves the area available for heat transfer. This results in a higher pressure drop in the channel. If the diameter of the cooling channel is increased, a higher flow rate is required to achieve turbulence. Thus, a balance has to be struck between the diameter and length of the cooling circuits, and the pressure and volume characteristics of the cooling pump.

This result is used to evaluate the cooling circuit's efficiency at heat transfer. You can use this result to check that the Reynolds number is adequate during all cooling stages for which active temperature control is desired. Check the analysis log for the actual time when the cooling stage changes. This Reynolds number result helps to guide a cooling system design change if that is required.

Things to look for

When viewing the Cooling circuit Reynolds number for RTM (transient from start-up) result, check the following:

• The Reynolds number should be greater than 4,000 for cooling circuits actively involved in heating or cooling the part. This is to make the coolant flow turbulent and hence efficient at heat transfer.
• The ideal Reynolds number is 10,000.