Concept explainers
Solve the nondimensional transient heat conduction equation in two dimensions, which represents the transient temperature distribution in an insulated plate. The governing equation is
where
Boundary conditions |
|
|
Initial conditions |
|
|
Solve using the alternating direction-implicit technique. Write a computer program to implement the solution. Plot the results using a three-dimensional plotting routine where the horizontal plan contains the x and y axes and the z axis is the dependent variable u. Construct several plots at various times, including the following: (a) the initial conditions; (b ) one intermediate time, approximately halfway to steady state; and (c ) the steady-state condition.
Want to see the full answer?
Check out a sample textbook solutionChapter 32 Solutions
EBK NUMERICAL METHODS FOR ENGINEERS
- Shape Factor Conduction Problem A cylindrical pipeline that is used for the transport of crude oil is buried in the soil horizontally such that its centerline is 1.5 m (z) below the surface. The pipe has the outer diameter of 0.5 m (D) and is coated with a 100 mm thick layer of glass insulation on the outside. Assume that heated oil at 120 °C flows through the pipe and the soil surface temperature is at 0 °C (T2). The soil thermal conductivity is known as 0.5 W/m-K, and the glass insulation thermal conductivity is known as 0.07 W/m-K. What is the rate of heat loss per unit length of the pipe (W/m)? Soil Glass insulation Oil, Tarrow_forwardYou are asked to estimate the maximum human body temperature if the metabolic heat produced in your body could escape only by tissue conduction and later on the surface by convection. Simplify the human body as a cylinder of L=1.8 m in height and ro= 0.15 m in radius. Further, simplify the heat transfer process inside the human body as a 1-D situation when the temperature only depends on the radial coordinater from the centerline. The governing dT +q""=0 dr equation is written as 1 d k- r dr r = 0, dT dr =0 dT r=ro -k -=h(T-T) dr (k-0.5 W/m°C), ro is the radius of the cylinder (0.15 m), h is the convection coefficient at the skin surface (15 W/m² °C), Tair is the air temperature (30°C). q" is the average volumetric heat generation rate in the body (W/m³) and is defined as heat generated per unit volume per second. The 1-D (radial) temperature distribution can be derived as: T(r) = q"¹'r² qr qr. + 4k 2h + 4k +T , where k is thermal conductivity of tissue air (A) q" can be calculated…arrow_forwardAn open system is often referred to as control volume, which is a properly selected region in space in which mass and energy can flow across the boundaries as figure 1.2. The boundary of a open thermodynamic system is called the control surface Across the Boundaries E = Yes F 0 = Yes w =Yes Control surface ass YES W CONTROL VOLUME energy YES Figure 1.2. A cooling/heating radiator is an example of such a system – give two more examples of such a system.arrow_forward
- Heat Transfer question In order to cool down a hot steel sphere (its diameter is 5 cm), CO2 gas is blown over it through a pipe with a diameter of 10 cm. The CO2 gas is kept at atmospheric pressure while moving through a smooth pipe at a speed of 6 m/sec. The gas temperature entering the pipe is 300K and exiting the pipe is 340 K. The pipe temperature at the entrance is 350K and at the exit is 550K. The sphere is located just about the pipe exit. Find the convective heat transfer coefficient of the gas moving in the pipe, the heat transfer rate at the pipe and the pipe length. What is the surface temperature of the sphere if the heat transfer rate between the sphere and the gas is 7W and its surface temperature is higher than the gas?arrow_forwardWhich formula is used to calculate the heat conduction in the AXIAL direction in a vertically located pipe segment whose inner and outer surfaces are perfectly insulated. Here r, is inner radius, r, outer radius, Tri pipe inner surface temperature, Tro pipe outer surface temperature, L is the length of the pipe, T the temperature on the lower surface, Ty the temperature on upper surface. Tu r; Tro rarrow_forward4.41 Solve the steady-state, 2-D heat conduction equation in the unit square, 0arrow_forward7. You are solving the steady-state temperature u(r, 0) in the semi-annular plate shown below, if a = 1,b = 2 and boundary conditions are u(1,0) = 0, u(r, 0) = 0, и(2,0) 3D Ө, 0 An(rn – r-")sin(n0), n=1 where A, is not yet determined. Continue from here to solve the steady-state temperature u(r,0) in this semi-annular plate.arrow_forwardThe initial temperature distribution of a 5 cm long stick is given by the following function. The circumference of the rod in question is completely insulated, but both ends are kept at a temperature of 0 °C. Obtain the heat conduction along the rod as a function of time and position ? (x = 1.752 cm²/s for the bar in question) 100 A) T(x1) = 1 Sin ().e(-1,752 (³¹)+(sin().e (-1,752 (²) ₁ + 1 3π TC3 .....) 100 t + ··· ....... 13) T(x,t) = 200 Sin ().e(-1,752 (²t) + (sin (3). e (-1,752 (7) ²) t B) 3/3 t + …............) C) T(x.t) = 200 Sin ().e(-1,752 (²t) (sin().e(-1,752 (7) ²) t – D) T(x,t) = 200 Sin ().e(-1,752 (²)-(sin().e (-1,752 (²7) ²) t E) T(x.t)=(Sin().e(-1,752 (²t)-(sin().e(-1,752 (²) t+ t + ··· .........) t +.... t + ··· .........) …..)arrow_forwardThe time evolution of the temperature of an object follows the Newton's cooling laws dT dx = -k(T - Ts), where the term k = 2.2 (1/s) is the heat transfer constant, and Tg = 25.6° C is the ambient temperature. The initial temperature of the object at time t = = 0 is T(t = 0) = 200°C. °C Use the Euler's method, and a time step of h=0.2s, calculate: When t = = 0.2s, T = °C When t 1s, T =arrow_forwardRelationship to Thermodynamics 4. An electrical resistor is connected to a battery, as shown schematically. After a brief transient, the resistor assumes a nearly uniform, steady-state temperature of 95 °C, while the battery and lead wires remain at the ambient temperature of 25 °C. Neglect the electrical resistance of the lead wires Battery V=24 V Resistor dEst dt Air T. = 25C Lead wire (a) Consider the resistor as a system about which a control surface is placed and Equation 1.12c is applied. Determine the corresponding values of Ein(W), Eg(W), Eout (W), and Est(W). If a control surface is placed about the entire system, what are the values of in, Eg, Eout, and Est? (1.12c) Est Ein - Eout + Eg (b) If electrical energy is dissipated uniformly with in the resistor, which is a cylinder of diameter D= 60 mm and length L=250 mm, what is the volumetric heat generation rate, (W/m3)? (c) Neglecting radiation from the resistor, what is the convection coefficient?arrow_forwardA solid steel cube is stored in a freezer, where the temperature is −20.0 ̊C. While the cube is in the freezer, you measure its side length (L) to be 1.75050 meters. The cube is then placed outside for a long time, so that the temperature of the cube reaches the temperature of the air outside. As a result, the side length increases to 1.75170 meters due to thermal expansion. The coefficient of linear expansion for steel is 12.0×10−6 ̊C−1. (a) What is the temperature of the air outside? Give your answer in degrees Celsius ( ̊C). (b) What is the volume of the cube when its temperature is 20.0 ̊C? Give your answer in cubic meters (m3).arrow_forward1 of 12 > 0/1 View Policies Show Attempt History Current Attempt in Progress X The sum of the second derivatives is zero for some values of a and b. The partial differential equation for two- dimensional steady-state conduction assuming no volumetric thermal energy generation and constant properties is + = 0 dx? dy? The following temperature distribution is valid under the stated conditions. T = ax + by True. False. True if a = -b. O It is not possible to determine whether the profile is valid. IIarrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_forward_ios
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning