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A cylindrical rod of stainless steel is insulated on its exterior surface except for the ends. The steady-state temperature distribution is
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Fundamentals of Heat and Mass Transfer
- 1.63 Liquid oxygen (LOX) for the space shuttle is stored at 90 K prior to launch in a spherical container 4 m in diameter. To reduce the loss of oxygen, the sphere is insulated with superinsulation developed at the U.S. National Institute of Standards and Technology's Cryogenic Division; the superinsulation has an effective thermal conductivity of 0.00012 W/m K. If the outside temperature is on the average and the LOX has a heat of vaporization of 213 J/g, calculate the thickness of insulation required to keep the LOX evaporation rate below 200 g/h.arrow_forward2.51 Determine by means of a flux plot the temperatures and heat flow per unit depth in the ribbed insulation shown in the accompanying sketch.arrow_forwardA section of a composite wall with the dimensions shown below has uniform temperatures of 200C and 50C over the left and right surfaces, respectively. If the thermal conductivities of the wall materials are: kA=70W/mK,kB=60W/mK, kC=40W/mK, and kP=20W/mK, determine the rate of heat transfer through this section of the wall and the temperatures at the interfaces. Repeat Problem 1.34, including a contact resistance of 0.1 K/W at each of the interfaces.arrow_forward
- 1. Question 1- Laplace Equation: Leibmann's Method The four sides of a square plate of side 12cm, made of homogenous material, are kept at a constant temperature 0°C and 100°C as shown in Figure 1. Using a grid of mesh 4cm and applying Leibmann's method, perform up to four (4) iteration to find the temperature at the various mesh points. 12cm U=100 ➤U=0 R u=100 U=100 ·X 12cm Figure 1 Showing Boundary Conditions for Given Problem.arrow_forwardIn this question, we are concerned with the evolution of the temperature u(x, t) in a homogeneous thin heat conducting rod of length L = 1. We can consider that the rod is laterally insulated as to have a one-dimensional problem. The evolution of the temperature is governed by the one-dimensional heat equation ди 0 0 = K Ət Əx2' Assume that this equation is subject to the following initial conditions u(x,0) = f(x) and boundary conditions (0, t) = 0 and ди (1,t) + и(1,t) — 0 (i) Discuss briefly the physical meaning of the boundary conditions.arrow_forwardquestion A B and Carrow_forward
- Q1/ The fumace wall consists of 120 mm wide Reftactory bricks Air gap Insulating fire bricks -Plaster refractory brick and 120 mm wide insulating fire brick separated by an air gap. The outside wall is covered with a 12 mm thickness of plaster. The inner surface of the wall is at 1090°C and the - 1090°C room temperature is 20°C. The heat transfer coefficient from the outside wall surface to the air in the room is 18 W/m² °C, and the resistance to heat flow of the air gap is 0.16 °C /W. If the thermal conductivities of the refractory brick, insulating fire brick, and plaster are 1.6, 0.3 and 0.14 W/m. °C, respectively calculates: (i) Rate at which heat is lost per m of the wall surface; (ii) Each interface temperature. -20°C - 120 mm 120 mm12 mmarrow_forward2. The lateral surface of a 50-units-long, thin vertical rod is insulated. When 0arrow_forward0 k(T) = k₂(1+B7) Plane wall L X Example:-Consider a plane wall of thickness L whose thermal conductivity varies linearly in a specified temperature range as K(T) =k₁ (1+BT) where k, and B are constants. The wall surface at x=0 is maintained at a constant temperature 1 of T₁ while the surface at x =L is maintained at T2, as shown in Figure . Assuming steady one-dimensional heat transfer, obtain a relation for:- (a) the heat transfer rate through the wall.. (b) the temperature distribution T(x) in the wall.arrow_forwardA 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?arrow_forwardThe initial temperature distribution on a 5 cm long bar is given as f(x)=x(5-x).The circumference of the rod is completely insulated and both ends are kept at 0°C.Find the heat conduction along the rod as a function of time and position.( α=1.752 cm2 )arrow_forward7. A composite wall consists of three materials, as shown in Figure 2. The inside wall temperature is 200°C and the outside air temperature is 50°C with a convection coefficient of 10 W/m²-K. Determine the temperature along the composite wall. Where A is the area of cross- section (can be taken to be equal to 1) and k is the conductivity. Problem is governed by the equation d²T -kA- = 0, 0arrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_forward_iosRecommended textbooks for you
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