Fundamentals of Heat and Mass Transfer
7th Edition
ISBN: 9780470917855
Author: Bergman, Theodore L./
Publisher: John Wiley & Sons Inc
expand_more
expand_more
format_list_bulleted
Videos
Question
Chapter 3, Problem 3.78P
To determine
An expression for the radial temperature distribution and find the heat rate which must be supplied to maintain a given temperature range.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Q1
For one -dimension heat transfer conduction consider a shielding wall for a nuclear
reactor. The wall receives a gamma-ray flux such that heat is generated within the
wall according to the relation
9x = 4, ( 2X+3)
Where q0 is the heat generation at the inner face of the wall exposed to the
ray Flux. Using this relation for heat generation, derive an expression for the
temperature distribution in a wall of thickness L, where the inside and outside
temperatures are maintained at Ti and TO, respectively. Also, obtain temperature in
the wall at X= 0.1 m. Assume, Ti-100 °C, TO=200 °C, L= 0.2 m, K = 40 w/ m.
°C, and q0 = 50 W
%D
gamma-
%3D
I 90
y FLUX
То
Ti
For one-dimension heat transfer conduction consider a shielding wall for a nuclear
reactor. The wall receives a gamma-ray flux such that heat is generated within the
wall according to the relation
9x = 90 (2X+3)
Where q0 is the heat generation at the inner face of the wall exposed to the gamma-
ray Flux. Using this relation for heat generation, derive an expression for the
temperature distribution in a wall of thickness L, where the inside and outside
temperatures are maintained at Ti and 70, respectively. Also, obtain temperature in
the wall at X= 0.1 m. Assume, Ti-100 °C, T0-200 °C, L= 0.2 m, K = 40 w / m.
°C, and q0 = 50 W
To
X-
1 90
Y FLUX
Ti
Determine the time needed to decrease the temperature of a solid cylinder from 40 C to 35 C if the ambient temperature is equal to 31 C.
The cylinder has a length equals to 0.9 m and diameter equals to 100 mm. The heat convective coefficient is equal to 1.3 W/m^2.K. The
cylinder has a conductivity equals to 2 W/m.K, a density equals to 1200 kg/m^3 and its Cp is equal to 4.700 kJ/kgK.
Select one:
a. 83325 s
O b. 10500s
O c. 45360 s
O d. 30050 s
Chapter 3 Solutions
Fundamentals of Heat and Mass Transfer
Ch. 3 - Consider the plane wall of Figure 3.1, separating...Ch. 3 - A new building to be located in a cold climate is...Ch. 3 - The rear window of an automobile is defogged by...Ch. 3 - The rear window of an automobile is defogged by...Ch. 3 - A dormitory at a large university, built 50 years...Ch. 3 - In a manufacturing process, a transparent film is...Ch. 3 - The walls of a refrigerator are typically...Ch. 3 - A t=10-mm -thick horizontal layer of water has a...Ch. 3 - A technique for measuring convection heat transfer...Ch. 3 - The wind chill, which is experienced on a cold,...
Ch. 3 - Determine the thermal conductivity of the carbon...Ch. 3 - A thermopane window consists of two pieces of...Ch. 3 - A house has a composite wall of wood, fiberglass...Ch. 3 - Consider the composite wall of Problem 3.13 under...Ch. 3 - Consider a composite wall that includes an...Ch. 3 - Work Problem 3.15 assuming surfaces parallel to...Ch. 3 - Consider the oven of Problem 1.54. The walls of...Ch. 3 - The composite wall of an oven consists of three...Ch. 3 - The wall of a drying oven is constructed by...Ch. 3 - The t=4-mm-thick glass windows of an automobile...Ch. 3 - The thermal characteristics of a small, dormitory...Ch. 3 - In the design of buildings, energy conservation...Ch. 3 - When raised to very high temperatures. many...Ch. 3 - A firefighter's protective clothing, referred to...Ch. 3 - A particular thermal system involves three objects...Ch. 3 - A composite wall separates combustion gases at...Ch. 3 - Approximately 106 discrete electrical components...Ch. 3 - Two stainless steel plates 10 mm thick are...Ch. 3 - Consider a plane composite wall that is composed...Ch. 3 - The performance of gas turbine engines may be...Ch. 3 - A commercial grade cubical freezer, 3 m on a side,...Ch. 3 - Physicists have determined the theoretical value...Ch. 3 - Consider a power transistor encapsulated in an...Ch. 3 - Ring-porous woods, such as oak, are characterized...Ch. 3 - A batt of glass fiber insulation is of density...Ch. 3 - Air usually constitutes up to half of the volume...Ch. 3 - Determine the density, specific heat, and thermal...Ch. 3 - A one-dimensional plane wall of thickness L is...Ch. 3 - The diagram shows a conical section fabricated...Ch. 3 - A truncated solid cone is of circular cross...Ch. 3 - From Figure 2.5 it is evident that, over a wide...Ch. 3 - Consider a tube wall of inner and outer radii ri...Ch. 3 - Measurements show that steady-state conduction...Ch. 3 - A device used to measure the surface temperature...Ch. 3 - A steam pipe of 0.12-m outside diameter is...Ch. 3 - Consider the water heater described in Problem...Ch. 3 - To maximize production and minimize pumping costs....Ch. 3 - A thin electrical heater is wrapped around the...Ch. 3 - A stainless steel (AISI 304) tube used to...Ch. 3 - A thin electrical heater is inserted between a...Ch. 3 - A 2-mm-diameter electrical wire is insulated by a...Ch. 3 - Electric current flows through a long rod...Ch. 3 - A composite cylindrical wall is composed of two...Ch. 3 - An electrical current of 700 A flows through a...Ch. 3 - A 0.20-m-diameter. thin-walled steel pipe is used...Ch. 3 - An uninsulated. thin-walled pipe of 100-mm...Ch. 3 - Steam flowing through a long. thin-walled pipe...Ch. 3 - A storage tank consists of a cylindrical section...Ch. 3 - Consider the liquid oxygen storage system and the...Ch. 3 - A spherical Pyrex glass shell has inside and...Ch. 3 - In Example 3.6. an expression was derived for the...Ch. 3 - A hollow aluminum sphere. with an electrical...Ch. 3 - A spherical tank for storing liquid oxygen on the...Ch. 3 - A spherical, cryosurgical probe may be imbedded in...Ch. 3 - Prob. 3.70PCh. 3 - Prob. 3.71PCh. 3 - A composite spherical shell of inner radius...Ch. 3 - The energy transferred from the anterior chamber...Ch. 3 - The outer surface of a hollow sphere of radius r2...Ch. 3 - A spherical shell of inner and outer radii r1 and...Ch. 3 - Prob. 3.76PCh. 3 - Prob. 3.77PCh. 3 - Prob. 3.78PCh. 3 - The air inside a chamber at T,i=50C is heated...Ch. 3 - Prob. 3.80PCh. 3 - A plane wall of thickness 0.1 m and thermal...Ch. 3 - Large, cylindrical bales of hay used to feed...Ch. 3 - Prob. 3.83PCh. 3 - Consider one-dimensional conduction in a plane...Ch. 3 - Consider a plane composite wall that is composed...Ch. 3 - An air heater may be fabricated by coiling...Ch. 3 - Prob. 3.87PCh. 3 - Consider uniform thermal energy generation inside...Ch. 3 - A plane wall of thickness and thermal conductivity...Ch. 3 - A nuclear fuel element of thickness 21, is covered...Ch. 3 - In Problem 3.79 the strip heater acts to guard...Ch. 3 - The exposed surface (x=0) of a plane wall of...Ch. 3 - A quartz window of thickness L serves as a viewing...Ch. 3 - For the conditions described in Problem 1.44....Ch. 3 - A cylindrical shell of inner and outer radii, ri...Ch. 3 - The cross section of a long cylindrical fuel...Ch. 3 - A long cylindrical rod of diameter 200 mm with...Ch. 3 - A radioactive material of thermal conductivity k...Ch. 3 - Radioactive wastes are packed in a thin-walled...Ch. 3 - Radioactive wastes (ktw=20W/mK) are stored in a...Ch. 3 - Unique characteristics of biologically active...Ch. 3 - Consider the plane wall, long cylinder, and sphere...Ch. 3 - One method that is used to grow nanowires...Ch. 3 - Consider the manufacture of photovoltaic silicon,...Ch. 3 - Copper tubing is joined to a solar collector plate...Ch. 3 - A thin flat plate of length L thickness t. and...Ch. 3 - The temperature of a flowing gas is to be measured...Ch. 3 - A thin metallic wire of thermal conductivity k,...Ch. 3 - A motor draws electric power Pelec from a supply...Ch. 3 - Consider the fuel cell stack of Problem 158. The...Ch. 3 - Consider a rod of diameter D, thermal conductivity...Ch. 3 - A carbon nanotube is suspended across a trench of...Ch. 3 - A probe of overall length L=200mm and diameter...Ch. 3 - A metal rod of length 2L diameter D, and thermal...Ch. 3 - A very long rod of 5-mm diameter and uniform...Ch. 3 - From Problem 1.71, consider the wire leads...Ch. 3 - Turbine blades mounted to a rotating disc in a...Ch. 3 - Prob. 3.127PCh. 3 - Prob. 3.128PCh. 3 - Prob. 3.129PCh. 3 - A brass rod 100 mm long and 5 mm in diameter...Ch. 3 - The extent to which the tip condition affects the...Ch. 3 - A pin fin of uniform. cross-sectional area is...Ch. 3 - The extent to which the tip condition affects the...Ch. 3 - A straight tin fabricated from 2024 aluminum alloy...Ch. 3 - Triangular and parabolic straight tins are...Ch. 3 - Two long copper rods of diameter D=10mm are...Ch. 3 - Circular copper rods of diameter D=1mm and length...Ch. 3 - During the initial stages of the growth of the...Ch. 3 - Consider two long, slender rods of the same...Ch. 3 - A 40-mm-long, 2-mm-diameter pin fin is fabricated...Ch. 3 - An experimental arrangement for measuring the...Ch. 3 - Finned passages are frequently formed between...Ch. 3 - The fin array of Problem 3.142 is commonly found...Ch. 3 - An isothermal silicon chip of width W=20mm on a...Ch. 3 - As seen in Problem 3.109, silicon carbide...Ch. 3 - A homeowner's wood stove is equipped with a top...Ch. 3 - Water is heated by submerging 50-mm-diameter,...Ch. 3 - As a means of enhancing heat transfer from...Ch. 3 - Consider design B of Problem 3.151. Over time....Ch. 3 - Determine the percentage increase in heat transfer...Ch. 3 - Aluminum fins of triangular profile are attached...Ch. 3 - An annular aluminum fin of rectangular profile is...Ch. 3 - Annular aluminum fins of rectangular profile are...Ch. 3 - It is proposed to air-cool the cylinders of a...Ch. 3 - Prob. 3.165PCh. 3 - Prob. 3.166PCh. 3 - Prob. 3.168PCh. 3 - Prob. 3.173PCh. 3 - Prob. 3.174PCh. 3 - Prob. 3.175PCh. 3 - A nanolaminated material is fabricated with an...
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
- Determine the time needed to decrease the temperature of a solid cylinder from 40 C to 35 C if the ambient temperature is equal to 31 C. The cylinder has a length equals to 0.9 m and diameter equals to 100 mm. The heat convective coefficient is equal to 9 W/m^2.K. The cylinder has a conductivity equals to 2 W/m.K, a density equals to 1200 kg/m^3 and its Cp is equal to 4.700 kJ/kgK.arrow_forwardProblem 2 Suppose that heat conduction occurs at a constant rate of đQ/dt in a hollow sphere with an inner radius of r, at temperature T, and an inner radius of r, at temperature T,. Show that for constant thermal conductivity K, the temperature difference between the two surfaces is given by dQ I dT ( 1 т, - т, 1 4л Кarrow_forwardHeat Transfer Mechanisms 5- In a certain experiment, cylindrical samples of diameter 4 cm and length 7 cm are used (see Fig.below). The two thermocouples in each sample are placed 3 cm apart. After initial transients, the electric heater is observed to draw 0.6 A at 110 V, and both differential thermometers read a temperature difference of 10°C. Determine the thermal conductivity of the sample.arrow_forward
- A plane wall of thickness 2L = 2*33 mm and thermal conductivity k = 7 W/m-K experiences uniform volumetric heat generation at a rate q˙, while convection heat transfer occurs at both of its surfaces (x = −L, + L), each of which is exposed to a fluid of temperature T∞ = 31°C. Under steady-state conditions, the temperature distribution in the wall is of the form T(x) = a + bx + cx2 where a = 85°C, b = −-218°C/m, c = −-23,942°C/m2, and x is in meters. The origin of the x-coordinate is at the midplane of the wall. (a) Sketch the temperature distribution and identify significant physical features. (b) What is the volumetric rate of heat generation q˙ in the wall? (c) Obtain an expression for the heat flux distribution qx″(x). Is the heat flux zero at any location? Explain any significant features of the distribution. (d) Determine the surface heat fluxes, qx″(−L) and qx″(+L). How are these fluxes related to the heat generation rate? (e) What are the convection coefficients…arrow_forwardConsider a heat conductor in the form of a long cylinder, with inner and outer radii R1 and R2, respectively. Heat is generated within the cylinder, where the temperature O(r, t) at position r and time t satisfies the modified heat equation = DV0 + H, where D is the thermal diffusivity, and H is proportional to the rate of heat production. The inner and outer surfaces of the cylinder are cooled by a fluid maintained at constant temperature Oo. (a) If the temperature is in a steady state and depends only on the distance r from the centre of the cylinder, use cylindrical coordinates (r, 0, 2) to write down an ordinary differential equation for O(r) valid in the region R1arrow_forward37. A long and slender shaft of diameter 2R and length L1 + L2 is insulated overlength L1 and produces heat only in this section while over length L2, it is exposedto a convection boundary (h, Tf). Write the governing differential equations andthe associated boundary conditions from which temperatures in sections L1 and L2can be obtained. Both ends may be treated as adiabatic surfaces.arrow_forwardIn a cylindrical fuel element for a gas-cooled nuclear reactor, the heat generation rate within the fuel element due to fission can be approximated by the relation: g(r) = g_0 [1 - (r/b)^2] W/m^3 where b is the radius of the fuel element and g_0 is constant. The boundary surface at r = b is maintained at a uniform temperature T_0. Assuming one-dimensional, steady-state heat flow, develop a relation for the temperature drop from the centerline to the surface of the fuel element. For radius b = 2 cm, the thermal conductivity k = 10 W/m middot K and g_0 = 2 times 10^7 W/m^3, calculate the temperature drop from the centerline to the surface.arrow_forwardan unsisulated 100 mm diameter steam pipe runs for 25 meters inside a room whose walls and air are at a temperature of 25 C. the superheated steam inside the pipe maintains the temperature at the pipe surface at 150 C. if the natural convection heat transfer coefficient of the air outside the pipe is 10 w/m^2 k and the surface emissivity is 0.8, compute for the total rate of heat transfer from the surface of the pipe in k/Warrow_forwardWrite clearly and explain.arrow_forwardA plane wall of thickness 2L = 30 mm and thermal conductivity k = 7 W/m-K experiences uniform volumetric heat generation at a rate q, while convection heat transfer occurs at both of its surfaces (x = − L, + L), each of which is exposed to a fluid of temperature T = 20°C. Under steady-state conditions, the temperature distribution in the wall is of the form T(x) = a + bx + cx² where a = 82.0°C, b = -210°C/m, c = -2x 10°C/m², and x is in meters. The origin of the x-coordinate is at the midplane of the wall. (a) What is the volumetric rate à of heat generation in the wall? (b) Determine the surface heat fluxes, q" (L)and q ( + L). (c) What are the convection coefficients for the surfaces at x = - Land x = + L? The volumetric rate of heat generation in the wall, in W/m³: q = i W/m³ The surface heat flux, in W/m²: qx ( - L) = i The surface heat flux, in W/m²: q (+ L) = i W/m² W/m² The convection coefficients for the surface at x = - L, in W/m²-K: h(- L) = i W/m².K The convection…arrow_forwardI need the answer as soon as possiblearrow_forward6. a. The heat flux applied to the walls of the biomass combustion furnace is 20 W/m2. The furnace walls have a thickness of 10 mm and a thermal conductivity of 12 W/m.K. If the wall surface temperature is measured to be 50oC on the left and 30oC on the right, prove that conduction heat transfer occurs at a steady state!b. Heating the iron cylinder on the bottom side is done by placing the iron on the hotplate. This iron has a length of 20 cm. The surface temperature of the hotplate is set at 300oC while the top side of the iron is in contact with the still outside air. To reach the desired hotplate temperature, it takes 5 minutes. Then it takes 15 minutes to measure the temperature of the upper side of the iron cylinder at 300oC. Show 3 proofs that heat transfer occurs transientlyarrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_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
Heat Transfer – Conduction, Convection and Radiation; Author: NG Science;https://www.youtube.com/watch?v=Me60Ti0E_rY;License: Standard youtube license