A coolant flows through a rectangular channel $($gallery$)$ within the body of a mold used to form metal injection parts. The gallery

dimensions are $a=90mm$ and $b=9\mathrm{.}5mm,$ and the fluid flow rate is $2\mathrm{.}1{10}^{-3}\frac{m^3}{s}.$ The coolant temperature is $15C,$ and the mold

wall is at an approximately uniform temperature of $140C.$

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. To evaluate the effects on thermal performance, determine the convection coefficients, in $\frac{W}{m^2}+K,$ of water and

ethylene glycol for this application.

h$\_$w $=$ W$/$m$^2$K

h$\_$eg $=$ W$/$m$^2$K