Nak (55%/44%), which is an alloy of sodium and potassium, is used to cool fast neutron nuclear reactors. the nak flows at a rate of latex: \dot{m} = 0.8 kg/sm ˙ = 0.8 k g / s through a d=40-mm-diameter tube that has a surface tube at t­m, i = 335 k and exits at an outlet temperature of tm, o =397 k. deter- mine the tube length l and the local convective heat flux at the tube exit.

Air at a pressure of 1atm and a temperature of 40 c is in parallel flow over the top surface of a flat plate that is heated to a uniform temperature of 120 c. the plate has a length of 0.40m (in the flow direction) and a width of 0.15m. the reynolds number based on the plate length is 50, 000. what is the rate of heat transfer from the plate to the air? if the free stream velocity of the air is doubled and the pressure is increased to 10 atm what is the rate of heat transfer?