HEAT+MASS TRANSFER-PHYSICAL ACCESS CODE
6th Edition
ISBN: 9781265896676
Author: CENGEL
Publisher: MCG CUSTOM
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 1, Problem 6CP
When modeling an engineering process, how is the right choice made between a simple but crude and a complex but accurate model? Is the complex model necessarily a better choice since it is more accurate?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
4. An operating parameter often used by power plant engineers is the heat rate. The heat rate is
defined as,
HR
Qbioler
Wnet
where Qbioler is the heat transfer rate (Btu/h) to the water in the boiler due to the combustion of a
fuel and Wnet is the net power (kW) delivered by the plant. In comparison, the thermal efficiency
of the power plant is defined as,
nth
Wnet
Qbioler
where the numerator and denominator have the same units. Consider a power plant that is
delivering 1000 MW of power while utilizing a heat transfer rate of 3570 MW at the boiler.
Determine the heat rate and thermal efficiency of this power plant.
3. A steam power plant has an average monthly net power delivery of 740 MW over the course of
a year. This power delivery is accomplished by burning coal in the boiler. The coal has a heating
value of 9150 Btu/lbm. The cost of the coal is $14.20/ton. The overall thermal efficiency of the
plant is,
nth
Wnet
Qboiler
0.26 = 26%
Determine the annual cost of the coal required to deliver the given average monthly power.
The shaft shown in the sketch is subjected to tensile
torsional and bending loads Determine the principal
stresses at the location of stress concentration
✓
D=45MR
F=3MM
1000-M
1000N
チ
d=30mm
500N
150 мм
MM-
120 MA-
Chapter 1 Solutions
HEAT+MASS TRANSFER-PHYSICAL ACCESS CODE
Ch. 1 - How does the science of heat transfer differ from...Ch. 1 - What is the driving force for (a) heat transfer,...Ch. 1 - How do rating problems in heat transfer differ...Ch. 1 - What is the difference between the analytical and...Ch. 1 - What is the importance of modeling in engineering?...Ch. 1 - When modeling an engineering process, how is the...Ch. 1 - On a hot summer day, a student turns his fan on...Ch. 1 - Consider two identical rooms, one with a...Ch. 1 - Prob. 9CPCh. 1 - Prob. 10CP
Ch. 1 - Prob. 11CPCh. 1 - An ideal gas is heated from 50C to 80C (a) at...Ch. 1 - What is heat flux? How is it related to the heat...Ch. 1 - What are the mechanisms of energy transfer to a...Ch. 1 - A logic chip used in a computer dissipates 3 W of...Ch. 1 - Consider a 150-W incandescent lamp. The filament...Ch. 1 - A 15-cm-diameter aluminum ball is to be heated...Ch. 1 - A 60-gallon water heated is initially filled with...Ch. 1 - Prob. 19PCh. 1 - Prob. 20PCh. 1 - Prob. 21PCh. 1 - Prob. 22PCh. 1 - Prob. 23PCh. 1 - Prob. 24PCh. 1 - Prob. 25PCh. 1 - Prob. 26PCh. 1 - A 5-m6-m8-m room is to be heated by an electrical...Ch. 1 - Prob. 28PCh. 1 - Air enters the duct of an air-conditioning system...Ch. 1 - Prob. 30PCh. 1 - Define thermal conductivity, and explain its...Ch. 1 - Which is a better heat conductor, diamond or...Ch. 1 - How do the thermal conductivity of gases and...Ch. 1 - Why is the thermal conductivity of superinsulation...Ch. 1 - Why do we characterize the heat conduction ability...Ch. 1 - What are the mechanisms of heat transfer? How are...Ch. 1 - Write down the expression for the physical laws...Ch. 1 - How does heat conduction differ from convection?Ch. 1 - Does any of the energy of the sun reach the earth...Ch. 1 - How does forced convection differ from natural...Ch. 1 - What is the physical mechanism of heat conduction...Ch. 1 - Consider heat transfer a windowless wall of house...Ch. 1 - Consider heat loss through two walls of house on a...Ch. 1 - Consider two houses that are identical except that...Ch. 1 - Consider two walls of a house that are identical...Ch. 1 - Define emissivity and absorptivity. What is...Ch. 1 - What is a blackbody? How do real bodies differ...Ch. 1 - A wood slab with a thickness 0.05 m is subjected...Ch. 1 - Prob. 49PCh. 1 - Prob. 50EPCh. 1 - The inner and outer surfaces of a 0.5-cm thick...Ch. 1 - Prob. 52PCh. 1 - Prob. 53PCh. 1 - The north wall of an electrically heated home is...Ch. 1 - Prob. 55PCh. 1 - Prob. 56PCh. 1 - Prob. 57PCh. 1 - A concreate wall a surface area of 20 m2 and a...Ch. 1 - Prob. 59PCh. 1 - Prob. 60PCh. 1 - Prob. 61PCh. 1 - Prob. 62EPCh. 1 - Air at 20C with a convection heat transfer...Ch. 1 - Prob. 64PCh. 1 - Prob. 65PCh. 1 - Prob. 66PCh. 1 - Prob. 67PCh. 1 - Prob. 68PCh. 1 - Prob. 69PCh. 1 - Prob. 70PCh. 1 - Prob. 71PCh. 1 - Prob. 72EPCh. 1 - Prob. 73PCh. 1 - Prob. 74PCh. 1 - Prob. 75PCh. 1 - Prob. 76PCh. 1 - Using the conversion factors between W and Btu/h,...Ch. 1 - The outer surface of a spacecraft in space has an...Ch. 1 - Consider a person whose expose surface are is 1.7...Ch. 1 - Prob. 80PCh. 1 - Two surfaces, one highly polished and the other...Ch. 1 - A spherical interplanetary probe with a diameter...Ch. 1 - Prob. 83PCh. 1 - Can all three modes of heat transfer occur...Ch. 1 - Can a medium involve (a) conduction and...Ch. 1 - The deep human body temperature of a healthy...Ch. 1 - We often turn the fan on in summer to help us...Ch. 1 - Prob. 88PCh. 1 - Prob. 89PCh. 1 - Prob. 90PCh. 1 - An electronic package with a surface area of 1 m2...Ch. 1 - Consider steady heat transfer between two large...Ch. 1 - Prob. 93PCh. 1 - Prob. 94PCh. 1 - A 2-in-diameter spherical ball whose surface is...Ch. 1 - Prob. 96PCh. 1 - Prob. 97PCh. 1 - A 3-m-internal-diameter spherical tank made of...Ch. 1 - Prob. 99PCh. 1 - Solar radiation is incident on a 5-m2 solar...Ch. 1 - Prob. 101PCh. 1 - Prob. 102PCh. 1 - Prob. 103EPCh. 1 - An AISI 304 stainless steel sheet is going through...Ch. 1 - Prob. 105PCh. 1 - Prob. 106PCh. 1 - Prob. 107PCh. 1 - Prob. 108CPCh. 1 - Prob. 109PCh. 1 - Prob. 110PCh. 1 - Prob. 111PCh. 1 - Prob. 112PCh. 1 - Prob. 113CPCh. 1 - Why is the metabolic rate of women, in general,...Ch. 1 - What is asymmetric thermal radiation How does it...Ch. 1 - How do (a) draft and (b) cold floor surfaces cause...Ch. 1 - Prob. 117CPCh. 1 - Why is it necessary to ventilate buildings? What...Ch. 1 - Consider a house in Atlanta, Georgia, that is...Ch. 1 - Prob. 120PCh. 1 - A 4m5m6m and room is to be heated by one ton (1000...Ch. 1 - Engine valves (cp=440J/kg.Kandp=7840kg/m3) are to...Ch. 1 - Prob. 123PCh. 1 - Prob. 124PCh. 1 - A 0.3 -cm-thick, 12-cm-high, and 18-cm-long...Ch. 1 - A 40-cm-long, 800-W electric resistance heating...Ch. 1 - It is well known that wind makes the cold air feel...Ch. 1 - An engine block with a surface area measured to be...Ch. 1 - Prob. 129PCh. 1 - Prob. 130PCh. 1 - Prob. 131PCh. 1 - Consider a person standing in a room maintained at...Ch. 1 - Prob. 133PCh. 1 - Prob. 134PCh. 1 - Prob. 135PCh. 1 - Prob. 136PCh. 1 - Prob. 137PCh. 1 - Prob. 138PCh. 1 - Prob. 139PCh. 1 - Prob. 140PCh. 1 - Prob. 141PCh. 1 - Prob. 142PCh. 1 - A 2-kW electric resistance heater submerged in...Ch. 1 - Prob. 144PCh. 1 - A cold bottled drink (m=2.5kg,cp=4200J/kg.K) at...Ch. 1 - Prob. 146PCh. 1 - Air enters a 12-m-long, 7-cm-diameter pipe at 50oC...Ch. 1 - Prob. 148PCh. 1 - Steady heat conduction occurs through a...Ch. 1 - Heat is lost through a brick wall (k=0.72W/m.K),...Ch. 1 - Prob. 151PCh. 1 - A 40-cm-long, 0.4-cm-diameter electric resistance...Ch. 1 - Prob. 153PCh. 1 - Prob. 154PCh. 1 - Over 90 percent of the energy dissipated by an...Ch. 1 - On a still, cleat night, the sky appears to be a...Ch. 1 - Prob. 157PCh. 1 - Prob. 158PCh. 1 - A persons head can be approximated as a...Ch. 1 - A person standing in a room loses heat to the air...Ch. 1 - Write an essay on how microwave ovens work, and...Ch. 1 - Using information form the utility bill for the...Ch. 1 - It is well know that at the same outdoor air...
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
- calculate moment of inertia of this tapered beam structurearrow_forwardThe system shown below is in statics equilibrium. Cable OB lies in the xy plane and makes a 30° angle with the positive x-axis. Cable OA lies along the negative y-axis. If the weight of the load being supported is 100 lb, determine the magnitude of the forces in all four cables: OA, OB, OC, and OD.arrow_forwardThis is a mechanics/statics problem involving finding internal reactions, V(x) and M(x). Please refer to image for details. I'm not sure about where to take cuts and how to formulate the equations as a function of x. For my support Reactions I got Ay = 1008.33 lb, By = 1416.67 lb and Cy = 175 lb. and for the first cut V(x) = 1008.33 -250(x) and M(x) = 1008.33x - 125x^2. I'm struggling with the equations for the 2nd and 3rd cut.arrow_forward
- As shown in the figure below, a ring is used to suspend a load and is supported by Cable OA and Spring OB. Given that the tension in Cable OA is 400 N, what is the weight of the load being supported? Assume the system is in static equilibrium.arrow_forward4. (a) State the conditions that must be met to ensure dynamic balance is achieved for long rotors. (b) A rotor carries three out-of-balance discs in planes A, B and C as shown in Figure 4. The out-of- balance mass x radius products of the rotor discs are tabulated in Table 4. The shaft is to be dynamically balanced by adding balancing masses in planes P and Q, spaced along the shaft at a distance da = 800 mm. Determine the magnitude mara and angular position of the balancing mass x radius product that must be added to plane Q. MBB Ов θε mdc Мага End View on Plane P P MBB MATA dA dB dc do Figure 4 moc Table 4 MATA = 0.6 kg mm 6A = 0° d₁ = 200 mm mers = 0.2 kg mm 6g = 45° dB = 400 mm mcrc = 0.4 kg mm Bc=240° dc = 600 mm Ans. (b) = 110.5°, moro = 0.2 kg mmarrow_forwardNeed help in adding demensioning am am so confusedarrow_forward
- Complete the following activity. Save as .pdf and upload to the assignment to the dropbox. 口 Use the general dimensioning symbols to correctly specify the following requirements on the drawing above.arrow_forwardplease solve and show workarrow_forwardWater is boiling in a 25 cm diameter aluminum pan (k=237 W/mK) at 95 degrees C. Heat is transferred steadily to the boiling water in the pan through its .5 cm thick flat bottom at a rate of 800 W. if the inner surface temp of the bottom of the pan is 108 degrees C determine the boiling heat transfer coefficent on the inner surface of the pan and the outer surface temp of the bottom of the pan.arrow_forward
- please solve and show workarrow_forwardplease solve and show workarrow_forwardA thin plastic membrane separates hydrogen from air. The molar concentrations of hydrogen in the membrane at the innner and outer surfaces are determined to be 0.045 and 0.002 kmol/m^3 respectiveley. The binary diffusion coefficent of hydrogen in plastic at the operation temp is 5.3*10^-10 m^2/s. Determine the mass flow rate of hydrogen by diffusion through the membrane under steady conditions if the thickeness of the membrane is 2mm and 0.5 mm.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
Heat Transfer – Conduction, Convection and Radiation; Author: NG Science;https://www.youtube.com/watch?v=Me60Ti0E_rY;License: Standard youtube license