Ice forms on a duct transporting liquid nitrogen. The duct consists of a circular hole, with diameter D=0.5 m, surrounded by square insulation, width=0.95 m, and thermal conductivity k=0.223 W/m*K. The inside of the duct is maintained at the boiling temperature of liquid nitrogen (T=-196 C). The outside ice experiences convection with T=20 C, and an effective h=5 W/m 2*K. Calculate the thickness of the ice and the total heat per length that the liquid nitrogen absorbs from the surroundings. Hint: Assume that the ice is thin enough that conduction through it (and only through the ice) is effectively 1-D and that the parameter of the ice is approximately the same as the duct (.95x.95m).
A laminated steel (E=200 GPa and nu=0.3) cylinder consists of a jacket with an inside diameter of 250mm and an outside diameter of 300mm shrunk onto a tube with an inside diameter of 150mm. The initial shrinkage pressure is 28MPa. Determine the following:
A. The initial interference required to produce ps=28 MPa.