P2) (50 pts.) A sphere of radius , and thermal conductivity of k=0.1 W/ mK is...
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 long cylinder of diameter D 0.012 m, thermal conductivity k 358 W/(mK), density p - 7614 kg/m3, specific heat c 418 J/(kgK) is initially at a uniform temperature of Ti-74°C. The cylinder is suddenly exposed to a gas at T,-18 ℃ The convection coefficient is h -17 W/(m2K). Verify that a lumped capacitance analysis can be used for the transient response of the cylinder temperature. What is the time t in seconds for the cylinder temperature to become Tf-32...
2-157 A long electrical resistance wire of radius r.-0.25 cm has a thermal conductivity kwire-15 W/m-K. Heat is generated uniformly in the wire as a result of resistance heating at a constant rate of 0.5 W/cm3. The wire is covered with polyethylene insulation with a thickness of 0.25 cm and thermal conductivity of ks 0.4 W/m K. The outer surface of the insulation is subjected to free convection in air at 20°C and a convection heat transfer coefficient of 2...
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...
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...
pts.) Consider a long resistance wire of radius ri-1.5 cm and thermal conductivity m'к in which heat is generated uniformly as a result of resistance heating at a e wire is embedded in a 1.0-cm-thick layer of ceramic whose thermal bTeam. W/m K. If the outer surface temperature of the ceramic layer is nstant rate. The nductivity is keramic-1.5 to be T,-45°C and the maximum temperature at the center is 375°C. Determine the ar generated per unit volume in (W/em)...
The upper surface of a 60-cm-thick solid plate (k = 237 W/m.K) is being cooled by water with temperature of 20°C. The upper and lower surfaces of the solid plate maintained at constant temperatures of 60°C and 120°C, respectively. Given: The thermal conductivity of the solid plate is given as k = 237 W/ mK. (T..+) The thermal conductivity of water at the film temperature of T, = =(60°C + 20°C)/2 = 40°C is kfluid = 0.631 W/mK. 1. value...
A plane wall is composed of two materials. Material A has a uniform heat generation of 100 kW/m3, a thermal conductivity of 50 W/mK, and a thickness of 10 cm. The inner surface of material A is well insulated. The other surface of material A is connected to Material B which has no generation with a thermal conductivity of 100 W/mK and a thickness of 20 cm. The outer surface of material B is cooled by ambient air at 300...
A plane wall with thermal conductivity of k, is insulated on one side and is exposed to ambient air at To and convection coefficient of h, on the other side. A heat source in the 3) wall is generating a uniform heat rate per unit volume of For one-dimensional steady-state conduction in the wall, derive a proper differential equation for the temperature by either using the heat equations or doing the energy balance. Identify proper boundary conditions and find the...
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...