A platen of thermal conductivity k 15 W m K is heated by flow of a hot fluid through channels of width L 20mm, with T ,i 200C and hi 500W m 2 K The upper surface of the platen is used to heat a process fluid at T o 25C with a convection coefficient of h n 250 W m 2 K The lower surface of the platen...

KNOWN Upper surface of a platen heated by hot fluid through the flow channels is used to heat a process fluid FIND a The maximum allowable spacing W b ...

A platen of thermal conductivity k = 15 W/m K is heated by flow of a

Question:

A platen of thermal conductivity k = 15 W/m ∙ K is heated by flow of a hot fluid through channels of width L = 20mm, with T_∞,i = 200°C and hi = 500W/m² ∙ K. The upper surface of the platen is used to heat a process fluid at T_∞.o = 25°C with a convection coefficient of h n = 250 W/m² ∙ K. The lower surface of the platen is insulated. To heat the process fluid uniformly, the temperature of the platen's upper surface must be uniform to within 5°C. Use a finite-difference method, such as that of IHT, or the finite-element method of FEHT to obtain the following results.

To.0 = 25°C h, = 250 W/m²-K Fluid O'00 Temperature uniformity of 5°C required Platen, k = 15 W/m•K Heating channel