.0124 W/cm-K. It has the shape of a rectangular bar with cross sectional area of 1 cm2and length of 3 cm. One end is maintained at 300 °C and the other end at 100 °C. The bar carries a current of 50 A and has resistivity of 1.5x10-3ohm-cm. Assuming the longitudinal surface is insulated, calculated the midpoint temperature in the ba

.0124 W/cm-K. It has the shape of a rectangular bar with cross sectional area of 1 cm2and length of 3 cm. One end is maintained at 300 °C and the other end at 100 °C. The bar carries a current of 50 A and has resistivity of 1.5x10-3ohm-cm. Assuming the longitudinal surface is insulated, calculated the midpoint temperature in the ba

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter3: Transient Heat Conduction

Section: Chapter Questions

Problem 3.1P: Consider a flat plate or a plane wall with a thickness L and a long cylinder of radius r0. Both of...

See similar textbooks

Similar questions

Determine k, thermal conductivity of a wall if q = 1000 kcal/m2 -hr at thickness, k = 33 mm and ∆t = 30°C.
The figure shows the cross section of a wall made of three layers. The thicknesses of the layers are L₁, L2=0.750 L₁, and L3 = 0.350 L₁. The thermal conductivities are k₁, k₂ = 0.840 k₁, and k3 = 0.780 k₁. The temperatures at the left and right sides of the wall are TH = 23 °C and Tc = -10 °C, respectively. Thermal conduction is steady. (a) What is the temperature difference AT2 across layer 2 (between the left and right sides of the layer)? If k2 were, instead, equal to 1.160 k₁, (b) would the rate at which energy is conducted through the wall be greater than, less than, or the same as previously, and (c) what would be the value of AT2? TH k₁ L₁ kg|kz kq L₂ L3 Tc
The figure shows the cross section of a wall made of three layers. The thicknesses of the layers are L1. L2 =0.500 L1. and L3 = 0.350 L1. The thermal conductivities are k1, k2 = 0.800 k1, and k3 = 0.680 k1. The temperatures at the left and right sides of the wall are TH = 20 °C and Tc = -10 °C, respectively. Thermal conduction is steady. (a) What is the temperature difference AT2 across layer 2 (between the left and right sides of the layer)? If k2 were, instead, equal to 1.100 k1, (b) would the rate at which energy is conducted through the wall be greater than, less than, or the same as previously, and (c) what would be the value of AT2? k1 ko k3 TH Tc L1 L9 L3 (a) AT2 = i (b) (c) AT2= i
A pipe made of material A have an outside diameter of 30 cm and inside diameter of 25 cm. The pipe is insulated by 31 cm thickness of Material B. The thermal conductivity of Material A and Material B is 70 and 11 respectively. If the w w temperature of the inner layer of the pipe is 1200K, the temperature of the outside layer pipe is 1100K, and the temperature on the outer layer of insulation is 350K. Find Q and Resistance to heat flow. L= 1.31 m m-K m-K
The inner and outer radii of a hollow cylinder are 15 mm (r, ) and 25 mm (r, ), respectively. The temperatures of the inner and outer walls are 400°C (T,) and 350°C (T,), respectively. The thermal conductivity of the cylinder material obeys the relationship K = (400-0.05T) W/mK where T is in degrees Celsius. Find the heat transferred from the hollow cylinder per unit length. The thermal conductivity,
Some types of bacteria containchains of ferromagnetic particles parallel to their long axis. The chainsact like small bar magnets that align these magnetotactic bacteria withthe earth’s magnetic field. In one experiment to study the response ofsuch bacteria to magnetic fields, a solenoid is constructed with copperwire 1.0 mm in diameter, evenly wound in a single layer to form a helicalcoil of length 40 cm and diameter 12 cm. The wire has a very thinlayer of insulation, and the coil is wound so that adjacent turns are justtouching. The solenoid, which generates a magnetic field, is in an enclosurethat shields it from other magnetic fields. A sample of magnetotacticbacteria is placed inside the solenoid. The torque on an individualbacterium in the solenoid’s magnetic field is proportional to the magnitudeof the magnetic field and to the sine of the angle between the longaxis of the bacterium and the magnetic-field direction What current is needed in the wire so that the magnetic field…
The image shows a plane wall of thicknessΔx = 21 cm with a thermal conductivity k=0.7 W/(mK). Given that the temperature at point 2 is 283 K and that the heat flux from points 1 to 2 is 154 W/m2 calculate the temperature at point 1 in Kelvin to 1dp (decimal place
Problem 7: Copper wire has a resistivity ρ = 1.7 × 10-8 Ω⋅m when at 20°C and it has a temperature coefficient α = 3.9 × 10-3 K-1. A solid cylinder of copper of length L = 85 cm and diameter D = 3.5 mm has one end held at T1 = 14°C and the other end is held at T2 = 210°C. The temperature increases linearly between the two ends of the cylinder. A) Consider a thin slice of the copper cylinder of thickness dx that is located a distance x from the left end of the cylinder. Write an equation for the temperature of this slice in terms of the variables x, L, T1, and T2. B) Determine the total resistance in milliohms.
A truncated solid cone is of circular cross section, and its diameter is related to the axial coordinate by an expression of the form D = ax3/2, where a = 2 m−1/2. The sides are well insulated, while the top surface of the cone at x1 is maintained at T1 and the bottom surface at x2 is maintained at T2. Conductivity k = 336 W/m-K (a) Obtain an expression for the temperature distribution T(x). (b) What is the rate of heat transfer across the cone if it is constructed of pure aluminum with x1 = 0.086 m, T1 = 113°C, x2 = 0.270 m, and T2 = 25°C?
A thin bar of length L = 3 meters is situated along the x axis so that one end is at x = 0 and the other end is at x = 3. The thermal diffusivity of the bar is k = 0.4. The bar's initial temperature f(x) = 300 degrees Celsius. The ends of the bar (x = 0 and x = 3) are then put in an icy bath and kept at a constant O degrees C. Let u(x, t) be the temperature in the bar at x at timet, with t measured in seconds. Find u(x, t) and then u7 (2, 0.1). Put uz (2, 0.1) calculated accurately to the nearest thousandth (3 decimal places) in the answer box.
A gas filled tube has 2 mm inside diameter and 25 cm length. The gas is heated by an electrical wire of diameter 50 microns (o.05 mm) located along the axis of the tube. Current and voltage drop across the heating element are 0.5A and 4 volts, respectively. If the measured wire and inside tube wall temps are 175C and 150C respectively, find the thermal conductivity of the gas filling the tube.
A coil consists of 2000 turns of copper wire having a circular - section of diameter 2.5 mm. The mean length per turn is 80 cm and the electrical resistivity of copper is 0.02 μΩ–m. Determine the resistance of the coil.