HEAT+MASS TRANSFER:FUND.+APPL.(LOOSE)
6th Edition
ISBN: 9781260440027
Author: CENGEL
Publisher: MCG
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
Chapter 2, Problem 118P
To determine
The average thermal conductivity between
The value of
The value of
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
The resistance of a copper wire used to make a motor is 0.5 Ω at 25 oC and 0.8 Ω at the motor’s operating temperature. Determine the operating temperature and the rise in temperature of the motor, given that copper has a temperature constant of 234.5 oC.
Some sections of the Alaska pipeline above ground are supported by vertical steel supports (k = 25 W/mK), which have a length of 1 m and a cross-sectional area of 0.05 m². Under normal operating conditions, the temperature variation along the length of the steel support is given by the expression T = 100 – 150x + 10x², where T and x have units of °C and m, respectively. Temperature variations in the cross-sectional area of the support are negligible. Evaluate the temperature and the heat conduction rate at the pipeline-support junction (x = 0) and at the support-soil interface (x = 1 m). Explain the difference in heat rates.
The rate of heat conduction through a plane wall is proportional to the average thermal conductivity, the wall area, and the temperature difference, but is inversely proportional to the ---------------.
Chapter 2 Solutions
HEAT+MASS TRANSFER:FUND.+APPL.(LOOSE)
Ch. 2 - How does transient heat transfer from steady heat...Ch. 2 - Is heat transfer a scalar or a vector quantity?...Ch. 2 - Does a hear flux vector at a point P on an...Ch. 2 - From a heat transfer point of view, what is the...Ch. 2 - What is heat generation in a solid? Give examples.Ch. 2 - Heat generation is also referred to as energy...Ch. 2 - In order to size the compressor of a new...Ch. 2 - In order to determine the size of the heating...Ch. 2 - Consider a round potato being baked in an oven....Ch. 2 - Consider an egg being cooked in boiling water in a...
Ch. 2 - Prob. 11CPCh. 2 - Consider the cooking process of a roast beef in an...Ch. 2 - Consider heat loss from a 200-L cylindrical hot...Ch. 2 - Consider a cold canned drink left on a dinner...Ch. 2 - Heat flux meters use a very sensitive device know...Ch. 2 - Prob. 16PCh. 2 - Consider a large 3-cm-thick stainless steel plate...Ch. 2 - In a nuclear reactor, heat is generated uniformly...Ch. 2 - Prob. 19PCh. 2 - Prob. 20EPCh. 2 - Writer down the one-dimensional transient heat...Ch. 2 - Writer down the one-dimensional transient heat...Ch. 2 - Starting with an energy balance on rectangular...Ch. 2 - Prob. 24PCh. 2 - Prob. 25PCh. 2 - Consider a medium in which the heat conduction...Ch. 2 - Consider a medium in which the heat conduction...Ch. 2 - Consider a medium in which the heat conduction...Ch. 2 - Consider a medium in which the heat conduction...Ch. 2 - Consider a medium in which the heat conduction...Ch. 2 - Consider a medium in which the heat conduction...Ch. 2 - Consider a medium in which the heat conduction...Ch. 2 - Starting with an energy balance on a volume...Ch. 2 - Prob. 34PCh. 2 - Prob. 35PCh. 2 - What is a boundary condition? How many boundary...Ch. 2 - What is an initial condition? How many initial...Ch. 2 - What is a thermal symmetry boundary condition? How...Ch. 2 - How is the boundary condition on an insulated...Ch. 2 - It is claimed that the temperature profile in a...Ch. 2 - Why do we try to avoid the radiation boundary...Ch. 2 - Consider an aluminum pan used to cook stew on top...Ch. 2 - Prob. 43PCh. 2 - Prob. 44PCh. 2 - Heat is generated in a long wire of radius ro at a...Ch. 2 - Consider a long pipe of inner radius r1, Outer...Ch. 2 - A 2-kW resistance heater wire whose thermal...Ch. 2 - Prob. 48PCh. 2 - Prob. 49PCh. 2 - Consider a spherical shell of inner radius r1,...Ch. 2 - A container consists of two spherical layers, A...Ch. 2 - A spherical metal ball of radius ro is heated in...Ch. 2 - Prob. 53PCh. 2 - It is stated that the temperature in a plane wall...Ch. 2 - Consider one-dimensional heat conduction through a...Ch. 2 - Consider a solid cylindrical rod whose side...Ch. 2 - Consider a solid cylindrical rod whose ends are...Ch. 2 - Prob. 58PCh. 2 - Prob. 59PCh. 2 - Prob. 60PCh. 2 - Prob. 61PCh. 2 - Consider a 20-cm-thick concrete plane wall...Ch. 2 - Prob. 63PCh. 2 - Prob. 64PCh. 2 - Prob. 65PCh. 2 - Prob. 66PCh. 2 - Prob. 67PCh. 2 - Prob. 68EPCh. 2 - Prob. 69PCh. 2 - Consider a chilled-water pipe of length L, inner...Ch. 2 - Prob. 71EPCh. 2 - Prob. 72PCh. 2 - Prob. 73PCh. 2 - Prob. 74PCh. 2 - Prob. 75PCh. 2 - Prob. 76PCh. 2 - Prob. 77PCh. 2 - Prob. 78PCh. 2 - Prob. 79PCh. 2 - Prob. 80PCh. 2 - Prob. 81PCh. 2 - Prob. 82CPCh. 2 - Does heat generation in a solid violate the first...Ch. 2 - Prob. 84CPCh. 2 - Prob. 85CPCh. 2 - Prob. 86CPCh. 2 - Prob. 87PCh. 2 - Prob. 88PCh. 2 - Consider a large 3-cm thick stainless steel plate...Ch. 2 - Prob. 90PCh. 2 - Prob. 91EPCh. 2 - Prob. 92PCh. 2 - Prob. 93PCh. 2 - Prob. 94PCh. 2 - Heat is generated uniformly at a rate of 3 kW per...Ch. 2 - Prob. 96PCh. 2 - Prob. 97PCh. 2 - Prob. 98PCh. 2 - Prob. 99PCh. 2 - Prob. 100PCh. 2 - Prob. 101PCh. 2 - Prob. 102PCh. 2 - Prob. 103PCh. 2 - Prob. 104PCh. 2 - Prob. 105PCh. 2 - Prob. 106PCh. 2 - Prob. 107PCh. 2 - Prob. 108PCh. 2 - Prob. 109CPCh. 2 - When the thermal conductivity of a medium varies...Ch. 2 - The temperature of a plane wall during steady...Ch. 2 - Consider steady one-dimensional heat conduction in...Ch. 2 - Prob. 113CPCh. 2 - Prob. 114PCh. 2 - Prob. 115PCh. 2 - Prob. 116PCh. 2 - Consider a plane wall of thickness L whose thermal...Ch. 2 - Prob. 118PCh. 2 - Prob. 119PCh. 2 - A pipe is used for transporting boiling water in...Ch. 2 - Prob. 121PCh. 2 - Prob. 122PCh. 2 - Consider a spherical shell of inner radius r1 and...Ch. 2 - Prob. 124PCh. 2 - A spherical tank is filled with ice slurry, where...Ch. 2 - Prob. 126CPCh. 2 - Prob. 127CPCh. 2 - Can a differential equation involve more than one...Ch. 2 - Prob. 129CPCh. 2 - Prob. 130CPCh. 2 - Prob. 131CPCh. 2 - Prob. 132CPCh. 2 - How is integation related to derivation?Ch. 2 - Prob. 134CPCh. 2 - Prob. 135CPCh. 2 - How is the order of a differential equation...Ch. 2 - How do you distinguish a linear differential...Ch. 2 - How do you recognize a linear homogeneous...Ch. 2 - How do differential equations with constant...Ch. 2 - What kinds of differential equations can be solved...Ch. 2 - Consider a third-order linear and homogeneous...Ch. 2 - A large plane wall, with a thickness L and a...Ch. 2 - Prob. 143PCh. 2 - Prob. 144EPCh. 2 - A spherical vessel has an inner radius r1 and an...Ch. 2 - Consider a short cylinder of radius r0 and height...Ch. 2 - Prob. 147PCh. 2 - Consider a 20-cm-thick large concrete plane wall...Ch. 2 - Prob. 149PCh. 2 - Prob. 150PCh. 2 - Prob. 151PCh. 2 - Prob. 152PCh. 2 - Prob. 153PCh. 2 - Prob. 154EPCh. 2 - Prob. 155PCh. 2 - Consider a water pipe of length L=17m, inner...Ch. 2 - Prob. 157PCh. 2 - In a manufacturing plant, a quench hardening...Ch. 2 - Consider a spherical reactor of 5-cm diameter...Ch. 2 - Consider a cylindrical sheel of length L, inner...Ch. 2 - A pipe is used for transporting boiling water in...Ch. 2 - A metal spherical tank is filled with chemicals...Ch. 2 - The heat conduction equation in a medium is given...Ch. 2 - Consider a medium in which the heat conduction...Ch. 2 - Consider a large plane wall of thicness L, thermal...Ch. 2 - A solar heat flux qs is incident on a sidewalk...Ch. 2 - A plane wall of thickness L is subjected to...Ch. 2 - Consider steady one-dimensional heat conduction...Ch. 2 - The conduction eqution boundary condition for an...Ch. 2 - Prob. 170PCh. 2 - Prob. 171PCh. 2 - The temperatures at the inner and outer surfaces...Ch. 2 - The thermal conductivity of a solid depends upon...Ch. 2 - Prob. 174PCh. 2 - Prob. 175PCh. 2 - Prob. 176PCh. 2 - Prob. 177PCh. 2 - Prob. 178PCh. 2 - Write essay on heat generation in nuc1e e1 rods....Ch. 2 - Write an interactive computer program to calculate...Ch. 2 - Prob. 181P
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Similar questions
- 1.10 A heat flux meter at the outer (cold) wall of a concrete building indicates that the heat loss through a wall of 10-cm thickness is . If a thermocouple at the inner surface of the wall indicates a temperature of 22°C while another at the outer surface shows 6°C, calculate the thermal conductivity of the concrete and compare your result with the value in Appendix 2, Table 11.arrow_forward2.30 An electrical heater capable of generating 10,000 W is to be designed. The heating element is to be a stainless steel wire having an electrical resistivity of ohm-centimeter. The operating temperature of the stainless steel is to be no more than 1260°C. The heat transfer coefficient at the outer surface is expected to be no less than in a medium whose maximum temperature is 93°C. A transformer capable of delivering current at 9 and 12 V is available. Determine a suitable size for the wire, the current required, and discuss what effect a reduction in the heat transfer coefficient would have. (Hint: Demonstrate first that the temperature drop between the center and the surface of the wire is independent of the wire diameter, and determine its value.)arrow_forward1.37 Mild steel nails were driven through a solid wood wall consisting of two layers, each 2.5-cm thick, for reinforcement. If the total cross-sectional area of the nails is 0.5% of the wall area, determine the unit thermal conductance of the composite wall and the percent of the total heat flow that passes through the nails when the temperature difference across the wall is 25°C. Neglect contact resistance between the wood layers.arrow_forward
- 2.2 A small dam, which is idealized by a large slab 1.2 m thick, is to be completely poured in a short Period of time. The hydration of the concrete results in the equivalent of a distributed source of constant strength of 100 W/m3. If both dam surfaces are at 16°C, determine the maximum temperature to which the concrete will be subjected, assuming steady-state conditions. The thermal conductivity of the wet concrete can be taken as 0.84 W/m K.arrow_forward2.34 Show that the temperature distribution in a sphere of radius . made of a homogeneous material in which energy is released at a uniform rate per unit volume , isarrow_forward2.38 The addition of aluminum fins has been suggested to increase the rate of heat dissipation from one side of an electronic device 1 m wide and 1 m tall. The fins are to be rectangular in cross section, 2.5 cm long and 0.25 cm thick, as shown in the figure. There are to be 100 fins per meter. The convection heat transfer coefficient, both for the wall and the fins, is estimated to be K. With this information determine the percent increase in the rate of heat transfer of the finned wall compared to the bare wall.arrow_forward
- A plane wall 15 cm thick has a thermal conductivity given by the relation k=2.0+0.0005T[W/mK] where T is in kelvin. If one surface of this wall is maintained at 150C and the other at 50C, determine the rate of heat transfer per square meter. Sketch the temperature distribution through the wall.arrow_forwardA steel pipe (outside diameter 100 mm) is covered with two layers of insulation. The inside layer, 40 mm thick, has a thermal conductivity of 0.07 W/(m K). The outside layer, 20 mm thick, has a thermal conductivity of 0.15 W/(m K). The pipe is used to convey steam at a pressure of 600 kPa. The outside temperature of insulation is 24°C. If the pipe is 10 m long, determine the following, assuming the resistance to conductive heat transfer in steel pipe and convective resistance on the steam side are negligible: a. The heat loss per hour. b. The interface temperature of insulation.arrow_forwardQuestion 2a) Give the Stefan Boltzman equation and define each term.[4]b) A electric room heater (radiator) element is 25 cm long and 4 cm in diameter. The element dissipates heat to the surroundings at 1500 W mainly by radiation, the surrounding temperature being 15°C. Determine the equilibrium temperature of the element surface.[4]c) A composite cylinder consists of 10 cm radius steel pipe of 25 mm thickness over which two layers of insulation 30 mm and 35 mm are laid. The conductivities are 25 W/mK, 0.25 W/mK and 0.65 W/mK. The inside is exposed to convection at 300°C with h 65 W/m2K.The outside is exposed to air at 30°C with h 15 W/m2K. Determinei. the heat loss/m,the interface temperatures.ii. The overall heat transfer coefficient.[4][4][2]arrow_forward
- A coil-shaped cooling pipe is made of SS-304 material. This pipe is 1 ft long, 0.4 inch outside diameter, and inch inside diameter. This coil cooling pipe is used to cool the water in the bath. The temperature of the inner coil pipe is 40oF while the outer coil in contact with water is 80oF. The thermal conductivity of SS-304 is a function of temperature where k(T) = 7.75 + (7.78 x 10-3).T where k is in Btu/h.ft.oF and T is in oF. Calculate the rate of heat dissipation in watts! (1287.7)arrow_forwardA ball made of steel alloy with a diameter of 2 millimeters is first heated to 800 degrees and then suddenly immersed in a water bath to cool down to 100 degrees. The materials from which the ball is made have a thermal conductivity coefficient of 54.94 w / mk, a heat capacity of 7860 kg / m3, a heat capacity of 450 j / kg. Also, the heat transfer coefficient is 41.66 2 / m2. a-)Find the temperature of the ball immersed in water after 10 seconds. b-)Find the time required to cool the ball to 400 degrees.arrow_forwardIP Heat Transport in the Human Body The core temperature of the human body is 37.0 ∘C∘C, and the skin, with a surface area of 1.40 m2m2, has a temperature of 34.0 ∘C∘C. Find the rate of heat transfer out of the body under the following assumptions: (i) The average thickness of tissue between the core and the skin is 1.20 cmcm; (ii) the thermal conductivity of the tissue is that of water. Express your answer using two significant figures. Without repeating the calculation of part A, what rate of heat transfer would you expect if the skin temperature were to fall to 31.0 ∘C∘C? Express your answer using two significant figures.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning
Principles of Heat Transfer (Activate Learning wi...
Mechanical Engineering
ISBN:9781305387102
Author:Kreith, Frank; Manglik, Raj M.
Publisher:Cengage Learning
Understanding Conduction and the Heat Equation; Author: The Efficient Engineer;https://www.youtube.com/watch?v=6jQsLAqrZGQ;License: Standard youtube license