A coolant flows through a rectangular channel (gallery) within the body of a mold used to form metal injection parts. The gallery dimensions are a = 90 mm and b = 9.5 mm, and the fluid flow rate is 1.3 x 10-3 m3/s. The coolant temperature is 15°C, and the mold wall is at an approximately uniform temperature of 140°C.

To minimize corrosion damage to the expensive mold it is customary to use a heat transfer fluid such as ethylene glycol, rather than process water. Compare the convection coefficients of water and ethylene glycol for this application. What is the trade-off between thermal performance and minimizing corrosion?

Gallery coolant, ri Alloy melt Mold body