HEAT+MASS TRANSFER-PHYSICAL ACCESS CODE
6th Edition
ISBN: 9781265896676
Author: CENGEL
Publisher: MCG CUSTOM
expand_more
expand_more
format_list_bulleted
Question
Chapter 3, Problem 75P
a.
To determine
The rate of heat transfer through the wall.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Draw the shear and bending-moment diagrams for the beam and loading shown, and
determine the maximum absolute value of (a) the shear, (b) the bending moment.
300 lb
240 lb 360 lb
C
D
E
A
4 in.
3 in.
4 in.
5 in.
Fig. P12.5
A commercial office building is located in the city of Lansing, Michigan, and is heatedusing a gaseous fuel with a heating value of 725 Btu/std ft3. The indoor designtemperature is 71ºF. The heat load for the building is known to be 250,000 Btu/hr. Thisheat load accounts for the fact that there are internal heat gains in the building, due tothe presence of people and electronic equipment (e.g., lights and radios). People in thebuilding are usually seated and involved in light activity.a) The furnace had an initial efficiency factor of 73% when installed, but since thenefficiency-improvement retrofits were implemented that raised the efficiency factorto its present value of 82%. The building was designed using the 99% designheating temperature value for the city to determine the outdoor design temperature.Evaluate the annual fuel quantity (in std ft3) required to heat the building, using thedegree-day or bin method.b) Seventy people use the building, but the occupancy pattern for the…
The volumetric flow rate of air through a duct transition of the type shown in Table 12-9b (rectangular with two parallel sides) is 2 m3/s. The duct before the transition issquare, with a height of 50 cm. The expansion ratio across the transition is 4 (i.e., theduct area after the transition is 4 times greater than the duct area before the transition).a) Determine the pressure loss (in Pa) across the transition if the exit from the duct isabrupt (i.e., the diverging angle of the transition is 180º).b) Determine the percentage reduction in pressure loss for a transition diverging angleof 20º compared to the one in part (a).c) The head HVAC engineer requires the pressure loss across the transition to bereduced to less than 50% of the pressure loss for an abrupt exit (i.e., the case in part(a)), and suggests a transition diverging angle of 45º. Will this new diverging angleachieve the required reduction in pressure loss? Justify your answer.d) For a transition diverging angle of 90º, the…
Chapter 3 Solutions
HEAT+MASS TRANSFER-PHYSICAL ACCESS CODE
Ch. 3 - Consider heat conduction through a wall of...Ch. 3 - Consider heat conduction through a plane wall....Ch. 3 - What does the thermal resistance of a medium...Ch. 3 - Can we defme the convection resistance for a unit...Ch. 3 - Consider steady heat transfer through the wall of...Ch. 3 - How is the combined heat transfer coefficient...Ch. 3 - Why are the convection and the radiation...Ch. 3 - Consider steady one-dimensional heat transfer...Ch. 3 - Someone comments that a microwave oven can be...Ch. 3 - Consider two cold canned drinks, one wrapped in a...
Ch. 3 - The bottom of a pan is made of a 4-mm-thick...Ch. 3 - Consider a surface of area A at which the...Ch. 3 - How does the thermal resistance network associated...Ch. 3 - Consider steady one-dimensional heat transfer...Ch. 3 - Consider a window glass consisting of two...Ch. 3 - Prob. 16PCh. 3 - Consider a person standing in a room at 20C with...Ch. 3 - Consider an electrically heated brick house...Ch. 3 - A12-cm18-cm circuit board houses on its surface...Ch. 3 - Water is boiling in a 25-cm-diameter aluminum pan...Ch. 3 - A cylindrical resistor element on a circuit board...Ch. 3 - Prob. 22PCh. 3 - A1.0m1.5m double-pane window consists of two...Ch. 3 - Prob. 24PCh. 3 - Prob. 25PCh. 3 - Prob. 26PCh. 3 - Prob. 27PCh. 3 - Prob. 28EPCh. 3 - To defog the rear window of an automobile, a very...Ch. 3 - A transparent film is to be bonded onto the top...Ch. 3 - To defrost ice accumulated on the outer surface of...Ch. 3 - Prob. 32PCh. 3 - Prob. 33PCh. 3 - Prob. 34PCh. 3 - Prob. 35PCh. 3 - Heat is to be conducted along a circuit board that...Ch. 3 - Prob. 37EPCh. 3 - Consider a house that has a 10m20-m base and a...Ch. 3 - Prob. 39EPCh. 3 - Prob. 40PCh. 3 - Prob. 41PCh. 3 - Prob. 42PCh. 3 - Prob. 43PCh. 3 - What is thermal contact resistance? How is it...Ch. 3 - Will the thermal contact resistance be greater for...Ch. 3 - Explain how the thermal contact resistance can be...Ch. 3 - A waII consists of two layers of insulation...Ch. 3 - Prob. 48CPCh. 3 - Consider two surfaces pressed against each other....Ch. 3 - Prob. 50PCh. 3 - Two 5-cm-diameter, 15-cm-long aluminum bars...Ch. 3 - Prob. 52PCh. 3 - Two identical aluminum plates with thickness of 30...Ch. 3 - A tvolayer wall is made of two metal plates, with...Ch. 3 - Prob. 55PCh. 3 - An aluminum plate and a stainless steel plate are...Ch. 3 - Prob. 57PCh. 3 - Prob. 58PCh. 3 - Prob. 59PCh. 3 - Prob. 60PCh. 3 - Prob. 61PCh. 3 - What are the two approaches used in the...Ch. 3 - The thermal resistance networks can also be used...Ch. 3 - When plotting the thermal resistance network...Ch. 3 - A 10-cm-thick vall is to be constructed with...Ch. 3 - Prob. 66EPCh. 3 - Prob. 67PCh. 3 - Prob. 68PCh. 3 - Prob. 69PCh. 3 - Prob. 70PCh. 3 - Prob. 71PCh. 3 - Prob. 72PCh. 3 - A 12-m-long and 5-m-high wall is constructed of...Ch. 3 - Prob. 74EPCh. 3 - Prob. 75PCh. 3 - Prob. 76PCh. 3 - Prob. 77PCh. 3 - What is an infinitely long cylinder? When is it...Ch. 3 - Can the thermal resistance concept be used for a...Ch. 3 - Consider a short cylinder whose top and bottom...Ch. 3 - Prob. 81PCh. 3 - Prob. 82PCh. 3 - Prob. 83PCh. 3 - Superheated steam at an average temperature 20C is...Ch. 3 - Prob. 85PCh. 3 - Prob. 86PCh. 3 - Prob. 87EPCh. 3 - Prob. 88EPCh. 3 - Prob. 89EPCh. 3 - Prob. 90PCh. 3 - Prob. 91PCh. 3 - Prob. 92PCh. 3 - Prob. 93EPCh. 3 - Prob. 94PCh. 3 - Prob. 95PCh. 3 - Prob. 96PCh. 3 - Liquid hydrogen is flowing through an insulated...Ch. 3 - Exposure to high concentrations of gaseous ammonia...Ch. 3 - A mixture of chemicals is flowing in a pipe...Ch. 3 - Ice slurry is being transported in a pipe...Ch. 3 - Prob. 101PCh. 3 - Prob. 102PCh. 3 - Prob. 103PCh. 3 - What is the critical radius of insulation? How is...Ch. 3 - Prob. 105CPCh. 3 - Prob. 106CPCh. 3 - Prob. 107CPCh. 3 - A pipe is insulated such that the outer radius of...Ch. 3 - A 0.083-in-diameter electrical wire at 90F is...Ch. 3 - Repeat Prob. 3-109E, assuming a thermal contact...Ch. 3 - Prob. 111PCh. 3 - Prob. 112PCh. 3 - Hot air is to be cooled as it is forced to flow...Ch. 3 - Prob. 114CPCh. 3 - Prob. 115CPCh. 3 - The fins attached to a surface are determined to...Ch. 3 - Explain how the fins enhance heat transfer from a...Ch. 3 - How does the overall effectiveness of a finned...Ch. 3 - Hot water is to be cooled as it flows through the...Ch. 3 - Consider two finned surfaces that are identical...Ch. 3 - The heat transfer surface area of a fin is equal...Ch. 3 - Does the (a) efficiency and (b) effectiveness of a...Ch. 3 - Two pin fins are identical, except that the...Ch. 3 - Two plate fins of constant rectangular cross...Ch. 3 - Two finned surfaces are identical, except that the...Ch. 3 - Obtain a relation for the fin efficiency for a fin...Ch. 3 - Prob. 127PCh. 3 - Consider a very long rectangular fin attached to a...Ch. 3 - Prob. 129PCh. 3 - Prob. 130PCh. 3 - Prob. 131PCh. 3 - Prob. 132PCh. 3 - Prob. 133EPCh. 3 - Prob. 134EPCh. 3 - Prob. 135PCh. 3 - Prob. 136PCh. 3 - Prob. 137PCh. 3 - Prob. 138PCh. 3 - Prob. 139PCh. 3 - Prob. 140PCh. 3 - Prob. 141PCh. 3 - Prob. 142PCh. 3 - Prob. 143PCh. 3 - Prob. 144PCh. 3 - Prob. 145PCh. 3 - Prob. 146PCh. 3 - The human body is adaptable to extreme climatic...Ch. 3 - Consider the conditions of Example 3-14 in the...Ch. 3 - Consider the conditions of Example 3-14 in the...Ch. 3 - Prob. 150PCh. 3 - What is a conduction shape factor? How is it...Ch. 3 - What is the value of conduction shape factors in...Ch. 3 - Prob. 153PCh. 3 - A thin-walled cylindrical container is placed...Ch. 3 - Prob. 155PCh. 3 - Prob. 156PCh. 3 - Prob. 157PCh. 3 - Prob. 158EPCh. 3 - Prob. 159PCh. 3 - Prob. 160PCh. 3 - Prob. 161PCh. 3 - Prob. 162PCh. 3 - Prob. 163PCh. 3 - Prob. 164PCh. 3 - Consider a house with a flat roof whose outer...Ch. 3 - Prob. 166PCh. 3 - Radioactive material, stored in a spherical vessel...Ch. 3 - What is the R-value of a wall? How does it differ...Ch. 3 - What is effective emissivity for a plane-parallel...Ch. 3 - Prob. 170CPCh. 3 - What is a radiant barrier? What kinds of materials...Ch. 3 - Consider a house whose attic space is ventilated...Ch. 3 - Prob. 173PCh. 3 - Prob. 174PCh. 3 - Prob. 175PCh. 3 - Prob. 176PCh. 3 - Prob. 177PCh. 3 - Prob. 178PCh. 3 - Determine the winter R-value and the U-factor of a...Ch. 3 - The overall heat transfer coefficient (the...Ch. 3 - Prob. 181EPCh. 3 - Determine the summer and winter R-values. in m2 ....Ch. 3 - The overall heat transfer coefficient of a wall is...Ch. 3 - Two homes are identical, except that the walls of...Ch. 3 - Prob. 185PCh. 3 - Consider two identical people each generating 60 V...Ch. 3 - Cold conditioned air at 12C is flowing inside a...Ch. 3 - Hot water is flowing at an average velocity of 1.5...Ch. 3 - Prob. 189PCh. 3 - Prob. 190PCh. 3 - Prob. 191PCh. 3 - Prob. 192PCh. 3 - Prob. 193PCh. 3 - Prob. 194PCh. 3 - Prob. 195PCh. 3 - Prob. 196PCh. 3 - Prob. 197PCh. 3 - A total of 10 rectangular aluminum fins...Ch. 3 - Prob. 199PCh. 3 - A plane wall surface at 200C is to be cooled with...Ch. 3 - Prob. 201PCh. 3 - Prob. 202PCh. 3 - Prob. 203PCh. 3 - Prob. 204PCh. 3 - A 0.6-rn-diameter, 1.9-rn-long cylindrical tank...Ch. 3 - Prob. 206PCh. 3 - Prob. 207PCh. 3 - A thin-walled spherical tank is buried in the...Ch. 3 - Heat is lost at a rate of 275 W per m2 area of a 1...Ch. 3 - Prob. 210PCh. 3 - Heat is generated steadily in a 3-cm-diameter...Ch. 3 - Prob. 212PCh. 3 - Prob. 213PCh. 3 - Prob. 214PCh. 3 - Prob. 215PCh. 3 - Prob. 216PCh. 3 - Consider two walls. A and B, with the same surface...Ch. 3 - Prob. 218PCh. 3 - A room at 20C air temperature is losing heat to...Ch. 3 - Prob. 220PCh. 3 - A 1-cm-diameter, 30cm-long fin made of aluminum...Ch. 3 - A hot surface at 80C in air at 20C is to be cooled...Ch. 3 - A cylindrical pin fin of diameter 0.6 cm and...Ch. 3 - A 3-cm-long. 2-nuti x 2-mm rectangular...Ch. 3 - Two finned surfaces with long fins are identical,...Ch. 3 - A 20-cm-diameter hot sphere at 120C is buried in...Ch. 3 - A 25-cm-diameter, 2.4-rn-long vertical cylinder...Ch. 3 - Prob. 228PCh. 3 - The walls of a food storage facility are made of a...Ch. 3 - The equivalent thermal resistance for the thermal...Ch. 3 - Prob. 231PCh. 3 - Prob. 232PCh. 3 - Prob. 233PCh. 3 - The fin efficiency is defined as the ratio of the...Ch. 3 - Prob. 235PCh. 3 - In the United States, building insulation is...Ch. 3 - Prob. 237PCh. 3 - A plane brick wall (k=0.7W/m.K) and is 10 cm...Ch. 3 - The temperature in deep space is close to absolute...Ch. 3 - In the design of electronic components, it is...Ch. 3 - Using cylindrical samples of the same material,...Ch. 3 - Find out about the wall construction of the cabins...Ch. 3 - Prob. 243PCh. 3 - A house with 200-m2 floor space is to be heated...
Knowledge Booster
Similar questions
- The volumetric flow rate of air through a duct transition of the type shown in Table 12-9b (rectangular with two parallel sides) is 2 m3/s. The duct before the transition issquare, with a height of 50 cm. The expansion ratio across the transition is 4 (i.e., theduct area after the transition is 4 times greater than the duct area before the transition).a) Determine the pressure loss (in Pa) across the transition if the exit from the duct isabrupt (i.e., the diverging angle of the transition is 180º).b) Determine the percentage reduction in pressure loss for a transition diverging angleof 20º compared to the one in part (a).c) The head HVAC engineer requires the pressure loss across the transition to bereduced to less than 50% of the pressure loss for an abrupt exit (i.e., the case in part(a)), and suggests a transition diverging angle of 45º. Will this new diverging angleachieve the required reduction in pressure loss? Justify your answer.d) For a transition diverging angle of 90º, the…arrow_forwardAuto Controls The figure is a schematic diagram of an aircraft elevator control system. The input to the systemin the deflection angle of the control lever , and the output is the elevator angle phi.show that for each angle theta of the control lever ,there is a corresponding elevator angle phi. Then find Y(s)/theta(s) and simplify the resulting transfer function . Also note from the diagram that y and phi is related Show full solution, no copied solutionsarrow_forwardhand-written solutions only. correct answers upvotedarrow_forward
- For a small house located in Ottawa, Ontario, there are three windows and three doors.You are assigned the task of determining the infiltration and related heat loss rates.It has been found experimentally that the pressure difference due to pressurization is -0.002 in. water. The pressure difference due to stack effect for this building is assumednegligible due to it having only a single floor. The dominant mean wind speed fordesign is assumed to be 15 mph. The house orientation is such that it is normal to thedominant mean wind direction.The house was built recently and all of the windows and doors are tight fitting. Thehouse construction and materials are typical for Ottawa, Ontario. The doors are 3 ftwide and 6.75 ft high. Each of the windows is double hung and each window has thefollowing overall dimensions: 3 ft wide and 4 ft high. (For clarity it is noted that eachdouble hung window has two glass segments that are 3 ft wide and 2 ft high.)The indoor design temperature is 70ºF and…arrow_forwardH.W1: Due to the applied loading, the element at point A on the solid cylinder is subjected to the state of stress shown. Determine the principal 6 ksi stresses acting at this point. 12 ksiarrow_forwardA wall is 7 m wide and 3 m high, and contains two doors and one window. Details onthe wall components are as follows:• The window is a triple-glazed glass window with a 6.4 mm space filled withargon gas. The window surfaces do not have any special surface emissivitycoatings. The window dimensions are 2 m by 1 m, and the window has analuminum sash with a thermal break.• The wall material has an overall heat-transfer coefficient of 0.5 W/(m2-ºC).• Each door is a solid core flush door made of wood, with a thickness of 4.5 cm.Also, each door is 2.1 m high and 0.8 m wide. Both doors are accompanied bymetal storm doors.a) Determine the overall heat-transfer coefficient [in W/(m2-ºC)] for the wallcombination (based on the overall dimensions of the wall-window-doorscombination), assuming winter conditions.b) The room is maintained at a temperature of 22ºC. If the heat flow rate through thewall is 0.4 kW at a certain time, what is the outdoor temperature at that time?Infiltration can be…arrow_forward
- Suppose that in a system with generalized coordinates 0₁ and 02, the equations of motion are found to be as follows. ƒ (×1,$1‚Ï‚½‚†2,$2,01,01,02, 02, 02, 02) = Q1 + C₁ (1,1,1,1,1,1,0₁,01,02,02,02,02) = C₂ In this system, a nonholonomic constraint for 12 = 0 was introduced to solve for a constraint force. r₁ is a constant. Which of the terms in these equations should go to zero, and why?arrow_forward3.) 13.152* - A sphere (m = 2 kg) is connected to a fixed point O by an inextensible cord (L = 1.2 m). The sphere rests on a frictionless horizontal surface at a distance of x = 0.5 m from O when it is given a velocity (V.) in a direction perpendicular to OA. It moves freely until it reach A', when the cord becomes taut. Find the maximum possible velocity v. if the impulse of the force exerted on the cord is not to exceed F = 3Ns.arrow_forward4.) 13.165* - Two billiard balls A & B (same mass m & diameter d = 2.37") are as shown. Ball A has velocity V₁ = 3 ft/s when it strikes B, which is at rest. B then moves in the x direction after impact. Find (a) angle 0, (b) the velocity of B after impact (VB'). Positional variables are x = 6" and y = 10", and e = 0.9.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University Press
Mechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSON
Thermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEY
Mechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage Learning
Engineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY
Elements Of Electromagnetics
Mechanical Engineering
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Oxford University Press
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:9780134319650
Author:Russell C. Hibbeler
Publisher:PEARSON
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:9781259822674
Author:Yunus A. Cengel Dr., Michael A. Boles
Publisher:McGraw-Hill Education
Control Systems Engineering
Mechanical Engineering
ISBN:9781118170519
Author:Norman S. Nise
Publisher:WILEY
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:9781337093347
Author:Barry J. Goodno, James M. Gere
Publisher:Cengage Learning
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:9781118807330
Author:James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:WILEY