Fundamentals of Heat and Mass Transfer
7th Edition
ISBN: 9780470917855
Author: Bergman, Theodore L./
Publisher: John Wiley & Sons Inc
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Chapter 9, Problem 9.109P
(a)
To determine
The heat transfer by free convection of air.
(b)
To determine
The heat transfer by free convection of water.
(c)
To determine
The heat transfer by free convection of engine oil.
(d)
To determine
The heat transfer by free convection of mercury.
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Students have asked these similar questions
Water at 25°C flows over a 30mm diameter cylinder with an embedded electrical heater. The
cylinder is 1m in length with a surface temperature of 90°C. If the supplied power is 28 kW/m,
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Question 4: Consider a sphere with a diameter of 25 mm and a surface temperature of 60°C that is
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Q1
(a) Differentiate between free and forced convection with examples.
(b) Define Nusselt (Nu), Prandtl (Pr), Reynolds (Re) and Grashof (Gr)
dimensionless numbers. State which numbers are used in free and forced
convection to determine the heat transfer coefficient.
(c) A vertical pipe 90 mm diameter and 2.5 m height is maintained at a
constant temperature of 125 °C, The pipe is surrounded by still
atmospheric air at 25 °C. Find heat loss by natural convection.
Properties of water at 75 °C:
Density =
1.0145 kg/m³
Kinematic viscosity = 20.55 x10-6 m²/s
Prandtl number (Pr) = 0.693
Thermal conductivity (k) = 30.06 x 10-3 W/m K
g × ß x L³ × AT
Grashof number, Gr =
V²
Nu =
0.10(GrPr)0.333
Chapter 9 Solutions
Fundamentals of Heat and Mass Transfer
Ch. 9 - The one-dimensional plane wall of Figure 3.1 is of...Ch. 9 - Using the values of density for water in Table...Ch. 9 - Consider an object of Characteristic length 0.01 m...Ch. 9 - To assess the efficacy of different liquids for...Ch. 9 - In many cases, we are concerned with free...Ch. 9 - The heat transfer rate due to free convection from...Ch. 9 - Consider a large vertical plate with a uniform...Ch. 9 - For laminar free convection flow on a vertical...Ch. 9 - Consider an array of vertical rectangular tins,...Ch. 9 - A number of thin plates are to be cooled by...
Ch. 9 - Prob. 9.11PCh. 9 - Prob. 9.13PCh. 9 - The plate described in Problem 9.14 has been used...Ch. 9 - Determine the average convection heat transfer...Ch. 9 - Consider a vertical plate of dimension 0.025m0.50m...Ch. 9 - During a winter day, the window of a patio door...Ch. 9 - Prob. 9.20PCh. 9 - A household oven door of 0.5-m height and 0.7-m...Ch. 9 - Consider a vertical, single-pane window of...Ch. 9 - Consider laminar flow about a vertical isothermal...Ch. 9 - Consider the conveyor system described in Problem...Ch. 9 - Prob. 9.25PCh. 9 - Consider an experiment to investigate the...Ch. 9 - The vertical rear window of an automobile is of...Ch. 9 - Prob. 9.28PCh. 9 - Prob. 9.29PCh. 9 - Prob. 9.30PCh. 9 - A refrigerator door has a height and width of...Ch. 9 - In the central receiver concept of a solar power...Ch. 9 - Prob. 9.34PCh. 9 - Airflow through a long, 0.2-m-square air...Ch. 9 - Prob. 9.36PCh. 9 - An electrical heater in the form of a horizontal...Ch. 9 - Consider a horizontal 6-mm-thick, 100-mm-long...Ch. 9 - Prob. 9.39PCh. 9 - Prob. 9.40PCh. 9 - Prob. 9.41PCh. 9 - Many laptop computers are equipped with thermal...Ch. 9 - Prob. 9.43PCh. 9 - At the end of its manufacturing process, a silicon...Ch. 9 - Integrated circuit (IC) boards are stacked within...Ch. 9 - Prob. 9.48PCh. 9 - Prob. 9.50PCh. 9 - Prob. 9.51PCh. 9 - Prob. 9.52PCh. 9 - Prob. 9.53PCh. 9 - Prob. 9.54PCh. 9 - Prob. 9.55PCh. 9 - Prob. 9.56PCh. 9 - Prob. 9.57PCh. 9 - A horizontal tube of 12.5-mm diameter with an...Ch. 9 - Prob. 9.60PCh. 9 - Prob. 9.61PCh. 9 - Prob. 9.63PCh. 9 - Prob. 9.64PCh. 9 - Common practice in chemical processing plants is...Ch. 9 - Consider the electrical heater of Problem 7.49. If...Ch. 9 - Prob. 9.67PCh. 9 - A billet of stainless steel, AISI 316, with a...Ch. 9 - Lone stainless steel rods of 50-mm diameter are...Ch. 9 - Hot air flows from a furnace through a...Ch. 9 - A biological fluid moves at a flow rate of...Ch. 9 - A sphere of 25-mm diameter contains an embedded...Ch. 9 - Prob. 9.79PCh. 9 - A vertical array of circuit boards is immersed in...Ch. 9 - Prob. 9.81PCh. 9 - The front door of a dishwasher of width 580 mm has...Ch. 9 - A natural convection air healer consists of an...Ch. 9 - A bank of drying ovens is mounted on a rack in a...Ch. 9 - Prob. 9.85PCh. 9 - Prob. 9.86PCh. 9 - Prob. 9.87PCh. 9 - To reduce heat losses, a horizontal rectangular...Ch. 9 - Prob. 9.89PCh. 9 - Prob. 9.90PCh. 9 - Prob. 9.91PCh. 9 - Prob. 9.92PCh. 9 - A 50-mm-thick air gap separates two horizontal...Ch. 9 - Prob. 9.94PCh. 9 - A vertical, double-pane window, which is 1 m on a...Ch. 9 - The top surface (0.5m0.5m) of an oven is 60°C for...Ch. 9 - Prob. 9.97PCh. 9 - Prob. 9.98PCh. 9 - Consider the cylindrical. 0.12-m-diamter radiation...Ch. 9 - Prob. 9.100PCh. 9 - A solar collector design consists of an inner tube...Ch. 9 - Prob. 9.104PCh. 9 - Prob. 9.105PCh. 9 - Liquid nitrogen is stored in a thin-walled...Ch. 9 - Prob. 9.108PCh. 9 - Prob. 9.109PCh. 9 - Prob. 9.110PCh. 9 - Prob. 9.111PCh. 9 - Prob. 9.114PCh. 9 - Prob. 9.115PCh. 9 - Prob. 9.116PCh. 9 - Prob. 9.117PCh. 9 - A water bath is used to maintain canisters...Ch. 9 - On a very Still morning, the surface temperature...Ch. 9 - Fuel cells similar to the PEM cell of Example 1.5...
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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
- A thin plate with a length of 0.4m is cooled by vertical suspension in a very large box filled with quiescent carbon monoxide at a temperature of 44°C. If the plate surface temperature is 80°C, please answer the following: 1. What is the thickness of the free convection boundary layer at the upper edge of the plate? 2. What is the velocity in the x-direction at half the plate length?arrow_forwardExperiment No. (5) Heat Transfer, Power Input and Surface temperature Questions and Discussions 1. What is the difference between natural and forced convection heat transfer? 2. What sources of error are there in this experiment? 3. Mention the parameters you utilized during the calculation and discuss them briefly. 4. In what functions does Nusselt number in natural convection differ from forced convection, Discuss. 5. Give two examples of natural convection heat transfer. 6. In natural convetion, what makes the hot part of fluid to move?arrow_forwardTwo vertical plates, each 200 mm high and at 90°C are placed in a tank of water at 30 °C. Calculate the minimum spacing which will prevent interference of the free convection thermal boundary layers. (k-0.674 W/mK, kinematic viscosity 0.556x 10 m/s, Pr-3.54). If the plates orientation is changed to horizontal what will be the minimum spacing which will prevent interference of the free convection thermal boundary layersarrow_forward
- A sphere of 74 mm diameter is moving through the air at a velocity of 0.035 m/s. The surface temperatureof the sphere is uniform at 40◦C and the air temperature is 20◦C. What is the average convection coefficientbetween the sphere and airarrow_forward(B) Explain the difference between forced and free convectionarrow_forwardExperiment No. (5) Heat Transfer, Power Input and Surface temperature 4. In what functions does Nusselt number in natural convection differ from forced convection, Discuss.arrow_forward
- (A) Answer the following: (1) Explain the concept of convection heat transfer. What are the methods used for calculating the heat transfer coefficient. (2) Define the following: a. Drag coefficient b. fully developed flow. c. Reynolds number. (B) Explain the difference between forced and free convectionarrow_forwardConsider two solid copper spheres, 1 and 2. Sphere 1 has twice the diameter of sphere 2. If both spheres are initially at 0 °C and placed in quiescent air at 25 °C, which sphere will reach air temnerature first?. sphere 1 sphere 2 both spheres will reach temperature at the same timearrow_forwardquestion in image need help with part c onlyarrow_forward
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