Fundamentals Of Thermal-fluid Sciences In Si Units
Fundamentals Of Thermal-fluid Sciences In Si Units
5th Edition
ISBN: 9789814720953
Author: Yunus Cengel, Robert Turner, John Cimbala
Publisher: McGraw-Hill Education
bartleby

Videos

Question
Book Icon
Chapter 19, Problem 132RQ

(a)

To determine

The length of the tube.

(a)

Expert Solution
Check Mark

Explanation of Solution

Given:

The mass flow rate (m) is 1500kg/hr.

The diameter (D) of tube is 10mm.

The initial temperature (Ti) is 10°C.

The final temperature (Te) is 40°C.

The tube wall temperature (T) is 49°C.

Calculation:

Calculate the bulk mean fluid temperature (Tm) using the relation.

    Tm=[Te+Ti2]=[40°C+10°C2]=25°C

Refer table A-15 “Properties of saturated water”.

Obtain the following properties of water corresponding to the temperature of 25°C as follows:

ρ=997kg/m3k=0.607W/mKμ=0.891×103m2/scp=4180J/kgKPr=6.14

Calculate the rate of heat transfer (Q.) using the relation.

    Q˙=m˙cp(TeTi)=(1500kg/h)(4180J/kgK)((40°C+273)K(10°C+273)K)={(1500kg/h)(1h3600s)}(4180J/kgK)×30K=52250W

Calculate the velocity of water (V) using the relation.

  V=m.ρAc=(1500×160×60)kg/s(997kg/m3)π((10mm×1m1000mm)42)=5.321m/s

Calculate the Reynold number (Re) using the relation.

    Re=ρVDμ=(997kg/m3)(5.321m/s)(10mm×1m1000mm)0.891×103kg/ms=59540

The Reynolds number is greater than 10000 therefore flow is turbulent flow.

Calculate the Nusselt number (Nu) using the relation.

    Nu=0.023Re0.8Pr0.4=0.023×(59540)0.8(6.14)0.4=313.9

Calculate the heat transfer coefficient (h) using the relation.

    Nu=hDkh=kDNuh=0.607W/mK(10mm×1m1000mm)(313.9)h=19054W/m2K

Calculate the logarithmic mean temperature difference (ΔTlm) using the relation.

  (ΔTlm)=TiTeln(TTeTTi)=((10°C+273)K(40°C+273)K)ln((49°C)(40°C)(49°C)(10°C))=20.46K

Calculate the surface area (As) using the relation.

    Q.=hAsΔTlm52250W=(19054W/m2K)As(20.46K)As=0.134m2

Calculate the length (L) of the tubes using the relation.

    As=πDLL=AsπD=0.134m2π(10mm×1m1000mm)=4.26m

Thus, the length of the tube is 4.26m.

(b)

To determine

The outlet temperature of water.

(b)

Expert Solution
Check Mark

Explanation of Solution

Given:

If the tube length is doubled.

Calculation:

Calculate the outlet temperature (Te) of water by using relation.

    m.cp(TeTi)=hAsΔTlmm.cp(TeTi)=hAsTiTeln(TsTeTsTi)[(1500×160×60)kg/s×(4180J/kgK)(Te10°C)]=[(19054W/m2K)(2×0.134m2)×[(10°CTe)ln(49°CTe49°C10°C)]]1741.66J/s(Te10)=5106.47[(10°CTe)ln(49°CTe39°C)]

Use trial error method to solve the above equation.

Assume Te=45°C

1741.66J/s(45°C10°C)=5106.47[(10°C45°C)ln(49°C45°C39°C)]11.9315.36

Since, the left hand side and right hand is not equal therefore, this assumption is wrong.

Assume Te=46°C.

    1741.66J/s(46°C10°C)=5106.47[(10°C46°C)ln(49°C46°C39°C)]12.2714.03

Since, the left hand side and right hand is not equal therefore, this assumption is wrong.

Assume Te=47°C

    1741.66J/s(47°C10°C)=5106.47[(10°C47°C)ln(49°C47°C39°C)]12.61=12.46

Since, the left hand side and right hand is equal therefore, this assumption is correct.

Thus, the outlet temperature of the water is 47°C.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
Using graphical methods, draw the pressure angle at the position shown in (a) and (b). e |------- R = Cam Base Radius e = Follower Offset ẞ₁ = Section Duration 1 B₁ = Section Duration 2 ẞ₂ = Section Duration 3 В2 B₁ Follower Position ww R ẞ3 (a) Reference Radial (b)
The figure below illustrates a graph that has a variable load torque and constant drive torque. Each cycle lasts three revolutions (6л radians). Torque (N-m) 600 550 400 1 200 TD= 225 N-m 2 + -T₁ 3 4 1 + 0 In addition, the rotation speed is @o steady-state conditions, determine 1. the average power required, 2πT 4π 5πT 6п Ꮎ = 180° rpm = 18.85 rad/sec, Imachine 125 kg-m². Assuming 2. the maximum and minimum rotational speeds throughout a cycle, 3. the mass of a 0.6-meter-diameter solid disc flywheel to produce Cs = 0.025.
An elastic cord is stretched between 2 points A and B located 2y = 0.8 m apart in the horizontal plane. When stretched directly between A and B, the tension is P₂ = 40 N. The cord is then stretched as shown until its midpoint C has moved through x = 0.3 m to C', and a force of F = 240 N is required to hold the cord at C'. A pellet (m = 0.1 kg) is placed at C' and the cord is released. Find the speed of the pellet as it passes through C.

Chapter 19 Solutions

Fundamentals Of Thermal-fluid Sciences In Si Units

Ch. 19 - The upper surface of a 50-cm-thick solid plate (k...Ch. 19 - Prob. 12PCh. 19 - During air cooling of oranges, grapefruit, and...Ch. 19 - During air cooling of steel balls, the convection...Ch. 19 - Prob. 15PCh. 19 - Water at 43.3°C flows over a large plate at a...Ch. 19 - Prob. 17PCh. 19 - Hot engine oil at 150°C is flowing in parallel...Ch. 19 - Prob. 19PCh. 19 - Prob. 22PCh. 19 - Prob. 23PCh. 19 - Prob. 24PCh. 19 - Prob. 25PCh. 19 - Prob. 27PCh. 19 - Prob. 28PCh. 19 - Prob. 30PCh. 19 - Prob. 31PCh. 19 - Solar radiation is incident on the glass cover of...Ch. 19 - Liquid mercury at 250°C is flowing with a velocity...Ch. 19 - Prob. 35PCh. 19 - Prob. 36PCh. 19 - Air is flowing in parallel over the upper surface...Ch. 19 - Prob. 40PCh. 19 - Consider laminar flow of air across a hot circular...Ch. 19 - Prob. 42PCh. 19 - A heated long cylindrical rod is placed in a cross...Ch. 19 - A person extends his uncovered arms into the windy...Ch. 19 - Prob. 46PCh. 19 - Prob. 47PCh. 19 - Prob. 49PCh. 19 - Consider a person who is trying to keep cool on a...Ch. 19 - A 12-ft-long, 1.5-kW electrical resistance wire is...Ch. 19 - Prob. 52PCh. 19 - Prob. 53PCh. 19 - Prob. 55PCh. 19 - Prob. 56PCh. 19 - A 10-cm-diameter, 30-cm-high cylindrical bottle...Ch. 19 - Prob. 58PCh. 19 - An incandescent lightbulb is an inexpensive but...Ch. 19 - Prob. 60PCh. 19 - Prob. 61PCh. 19 - Prob. 62PCh. 19 - A coated sheet is being dried with hot air blowing...Ch. 19 - Prob. 65PCh. 19 - Consider laminar forced convection in a circular...Ch. 19 - Consider turbulent forced convection in a circular...Ch. 19 - What does the logarithmic mean temperature...Ch. 19 - Prob. 69PCh. 19 - Prob. 70PCh. 19 - Prob. 71PCh. 19 - Prob. 72PCh. 19 - Prob. 73PCh. 19 - Cooling water available at 10°C is used to...Ch. 19 - Prob. 75PCh. 19 - Inside a condenser, there is a bank of seven...Ch. 19 - Prob. 79PCh. 19 - Prob. 81PCh. 19 - Prob. 82PCh. 19 - In a thermal system, water enters a 25-mm-diameter...Ch. 19 - Prob. 84PCh. 19 - Prob. 85PCh. 19 - Prob. 86PCh. 19 - Prob. 88PCh. 19 - Prob. 89PCh. 19 - Prob. 90PCh. 19 - Glycerin is being heated by flowing between two...Ch. 19 - Determine the convection heat transfer coefficient...Ch. 19 - Prob. 94PCh. 19 - Water is to be heated from 10°C to 80°C as it...Ch. 19 - Consider a fluid with a Prandtl number of 7...Ch. 19 - The hot water needs of a household are to be met...Ch. 19 - Prob. 98PCh. 19 - Prob. 99PCh. 19 - Hot air at atmospheric pressure and 85°C enters a...Ch. 19 - Prob. 102PCh. 19 - Prob. 104PCh. 19 - Prob. 105PCh. 19 - Prob. 106PCh. 19 - Prob. 107RQCh. 19 - Prob. 108RQCh. 19 - The passenger compartment of a minivan traveling...Ch. 19 - Prob. 110RQCh. 19 - Prob. 111RQCh. 19 - Prob. 112RQCh. 19 - Prob. 113RQCh. 19 - Prob. 114RQCh. 19 - Prob. 115RQCh. 19 - Prob. 116RQCh. 19 - Airstream at 1 atm flows, with a velocity of 15...Ch. 19 - Prob. 118RQCh. 19 - Prob. 119RQCh. 19 - Prob. 120RQCh. 19 - Prob. 121RQCh. 19 - A 3-m-internal-diameter spherical tank made of...Ch. 19 - Prob. 123RQCh. 19 - Prob. 124RQCh. 19 - Prob. 125RQCh. 19 - Prob. 126RQCh. 19 - Prob. 127RQCh. 19 - Prob. 128RQCh. 19 - Prob. 129RQCh. 19 - Prob. 130RQCh. 19 - Prob. 131RQCh. 19 - Prob. 132RQCh. 19 - Prob. 133RQCh. 19 - Prob. 134RQCh. 19 - Prob. 135RQCh. 19 - Prob. 136RQCh. 19 - Prob. 137RQCh. 19 - Prob. 138RQCh. 19 - Prob. 139RQCh. 19 - Prob. 140RQCh. 19 - Liquid water enters a 10-m-long smooth rectangular...
Knowledge Booster
Background pattern image
Mechanical Engineering
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
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Elements Of Electromagnetics
Mechanical Engineering
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Oxford University Press
Text book image
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:9780134319650
Author:Russell C. Hibbeler
Publisher:PEARSON
Text book image
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:9781259822674
Author:Yunus A. Cengel Dr., Michael A. Boles
Publisher:McGraw-Hill Education
Text book image
Control Systems Engineering
Mechanical Engineering
ISBN:9781118170519
Author:Norman S. Nise
Publisher:WILEY
Text book image
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:9781337093347
Author:Barry J. Goodno, James M. Gere
Publisher:Cengage Learning
Text book image
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:9781118807330
Author:James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:WILEY
Heat Transfer – Conduction, Convection and Radiation; Author: NG Science;https://www.youtube.com/watch?v=Me60Ti0E_rY;License: Standard youtube license