An 8" thick copper bulkhead (kept at 100 C by electrical heat) at the entrance of a flow reactor. The bulkhead is penetrated by a multitude of 0.25" diameter by 8" long cylindrical openings. The heated copper bulkhead is attached to 17" of excellent insulation, which thermal isolates the copper bulkhead from the reactor contents. 1" Outer diameter by 17" long copper rods are drilled with a 0.25" diameter center hole. The hollow rods are attached to the copper bulkhead to allow 0 C air to enter the reactor from an external blower through the insulation. Air enters at a velocity of 5m/s. What is the temperature of the air entering the reactor?
Note: heat is supplied to the air by the copper tube as it leaves the copper bulkhead; for a conservative estimate of the air temperature entering the reactor, you may assume the duty supplied to air within the copper tube (i.e., not the copper bulkhead) is Q=hAt(Tto-Tao), where Tto= tube temperature at air exit and Tao= exit air temperature.