5. A steel post (10 mm diameter, 0.5 m length) is placed vertically on top of a heated block of steel (steel thermal conductivity 50 Wm K1) with perfect contact. The core temperature of the block...
A long cylindrical rod of diameter 220 mm with thermal conductivity 0.5 W/m-K expe riences uniform volumetric heat generation of 25,000 W/m3. The rod is encapsulated by a circular sleeve having 7 W/m K. The outer surface of the sleeve is exposed to cross flow of air at 25°C with a convection coefficient of 25 W/m2-K. Find the temperature at the interface between the rod and sleeve, and on the outer surface. an outer diameter of 410 mm and thermal...
A long cylindrical rod of diameter 100 mm with thermal conductivity of 0.5 W/mK experiences uniform volumetric heat generation of 5.0 x 10 W/m². The rod is encapsulated by a circular sleeve having an outer diameter of 400 mm and a thermal conductivity of 4 W/mK. The outer surface of the sleeve is exposed to cross flow of air at 27°C with a convection coefficient of 25 W/m2K (a) Find the temperature at the Interface between the rod and sleeve...
A rod of diameter D = 25 mm and thermal conductivity of 60 W/m K protrudes from a furnace with a wall temperature of 200°C. The rod is welded to the furnace wall and is used as a hangar for instrumentation cables. To avoid damaging the cables, the surface temperature of last 100 mm of the rod must be kept below 100°C. The ambient air temperature is 25°C and the convection coefficient is 15 W/m2K. (a) Write the finite-difference equation for...
A very long rod of 5-mm diameter and uniform thermal conductivity k = 25 W/m-K is subjected to a heat treatment process. The center, 30-mm-long portion of the rod within the induction heating coil experiences uniform volumetric heat generation of 7.5 x 106 W/m3. The unheated portions of the rod, which protrude from the heating coil on either side, experience convection with the ambient air at T∞ = 20 °C and h = 10 W/m2K. Assume that there is no convection...
5. Problem 3.54 (Textbook) (20 points) KNOWN: Diameter of electrical wire. Thickness and thermal conductivity of rubberized sheath. Contact resistance between sheath and wire. Convection coefficient and ambient air temperature. Maximum allowable sheath temperature. FIND: Maximum allowable power dissipation per unit length of wire. Critical radius of insulation. SCHEMATIC: Air Wire Egen. D-2 mm Two Tini Tino To Ric = 3x10-4 m2-KW Insulation, t = 2 mm T= 20°C Ric Rcond conv k = 0.13 W/m-K Tmax = 50°C h...