Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
8th Edition
ISBN: 9781305387102
Author: Kreith, Frank; Manglik, Raj M.
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 1, Problem 1.21P
In an experimental set up in a laboratory, a long cylinder with a 5-cm diameter, and an electrical resistance heater inside its entire length is cooled with water flowing crosswise over the cylinder at
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
In a power plant, pipes transporting superheated vapor are very common. In a certain plant, superheated vapor is flowing at a rate of 0.3 kg/s inside a 5 cm diameter pipe of 10 m length. The air in the plant is maintained at 20oC while the surface temperature of the pipe is 100oC. If the temperature drop between the inlet and exit of the pipe is 30oC and the specific heat capacity of the vapor is 2190 kJ/kg.K, determine the convective heat transfer coefficient at the pipe surface. If necessary, how could this coefficient be increased?
Air flows in a pipe under fully developed conditions with an
average velocity of 1.25 m/s and a temperature of 24°C. The
pipe's inner diameter is 4 cm, and its length is 4 m. The first
half of the pipe is kept at a constant wall temperature of
100°C. The second half of the pipe is subjected to a constant
heat flux of 200 W. The properties of air at 80°C are p =
0.9994 kg/m³, k = 0.02953 W/m-K, v= 2.097 × 10-5 m²/s,
Cp = 1008 J/kg-K, and Pr=0.7154.
Air
1.25 m/s
2m
T₁ = 100°C
D = 4 cm
2m
ė, = 200 W
Determine the air temperature at the 2 m length.
The air temperature at the 2 m length is
°C.
A pipe in a manufacturing plant is transporting superheated vapor at a mass flow rate of 0.3 kg/s. The pipe is 10 m long and has an inner diameter of 5 cm and a wall thickness of 6 mm. The pipe has a thermal conductivity of 17 W/m⋅K, and the inner pipe surface is at a uniform temperature of 120° C. The temperature drop between the inlet and exit of the pipe is 7° C, and the constant pressure specific heat of vapor is 2 190 J/kg⋅°C. If the air temperature in the manufacturing plant is 25° C, determine the heat transfer coefficient as a result of convection between the outer pipe surface and the surrounding air.
Chapter 1 Solutions
Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
Ch. 1 - 1.1 On a cold winter day, the outer surface of a...Ch. 1 - 1.2 The weight of the insulation in a spacecraft...Ch. 1 - 1.3 A furnace wall is to be constructed of brick...Ch. 1 - 1.4 To measure thermal conductivity, two similar...Ch. 1 - To determine the thermal conductivity of a...Ch. 1 - A square silicon chip 7mm7mm in size and 0.5-mm...Ch. 1 - A cooling system is to be designed for a food...Ch. 1 - 1.80 Describe and compare the modes of heat loss...Ch. 1 - Heat is transferred at a rate of 0.1 kW through...Ch. 1 - 1.10 A heat flux meter at the outer (cold) wall of...
Ch. 1 - 1.11 Calculate the heat loss through a glass...Ch. 1 - 1.12 A wall with a thickness is made of a...Ch. 1 - 1.13 If the outer air temperature in Problem is...Ch. 1 - Using Table 1.4 as a guide, prepare a similar...Ch. 1 - 1.15 A thermocouple (0.8-mm-diameter wire) used to...Ch. 1 - Water at a temperature of 77C is to be evaporated...Ch. 1 - The heat transfer rate from hot air by convection...Ch. 1 - The heat transfer coefficient for a gas flowing...Ch. 1 - 1.19 A cryogenic fluid is stored in a...Ch. 1 - A high-speed computer is located in a...Ch. 1 - 1.21 In an experimental set up in a laboratory, a...Ch. 1 - 1.22 In order to prevent frostbite to skiers on...Ch. 1 - Using the information in Problem 1.22, estimate...Ch. 1 - Two large parallel plates with surface conditions...Ch. 1 - 1.25 A spherical vessel, 0.3 m in diameter, is...Ch. 1 - 1.26 Repeat Problem 1.25 but assume that the...Ch. 1 - Determine the rate of radiant heat emission in...Ch. 1 - 1.28 The sun has a radius of and approximates a...Ch. 1 - 1.29 A spherical interplanetary probe with a 30-cm...Ch. 1 - A spherical communications satellite, 2 m in...Ch. 1 - A long wire 0.7 mm in diameter with an emissivity...Ch. 1 - Wearing layers of clothing in cold weather is...Ch. 1 - A section of a composite wall with the dimensions...Ch. 1 - A section of a composite wall with the dimensions...Ch. 1 - Repeat Problem 1.35 but assume that instead of...Ch. 1 - 1.37 Mild steel nails were driven through a solid...Ch. 1 - Prob. 1.38PCh. 1 - 1.39 On a cold winter day, the outside wall of a...Ch. 1 - As a designer working for a major electric...Ch. 1 - 1.41 A heat exchanger wall consists of a copper...Ch. 1 - 1.43 A simple solar heater consists of a flat...Ch. 1 - A composite refrigerator wall is composed of 5 cm...Ch. 1 - An electronic device that internally generates 600...Ch. 1 - 1.47 A flat roof is modeled as a flat plate...Ch. 1 - A horizontal, 3-mm-thick flat-copper plate, 1-m...Ch. 1 - 1.49 A small oven with a surface area of is...Ch. 1 - A steam pipe 200 mm in diameter passes through a...Ch. 1 - 1.51 The inner wall of a rocket motor combustion...Ch. 1 - 1.52 A flat roof of a house absorbs a solar...Ch. 1 - Determine the power requirement of a soldering...Ch. 1 - 1.54 The soldering iron tip in Problem 1.53...Ch. 1 - Prob. 1.55PCh. 1 - A pipe carrying superheated steam in a basement at...Ch. 1 - Draw the thermal circuit for heat transfer through...Ch. 1 - 1.60 Two electric resistance heaters with a 20 cm...Ch. 1 - 1.63 Liquid oxygen (LOX) for the space shuttle is...Ch. 1 - The interior wall of a large, commercial walk-in...Ch. 1 - 1.67 In beauty salons and in homes, a ubiquitous...Ch. 1 - The heat transfer coefficient between a surface...Ch. 1 - The thermal conductivity of fibreglass insulation...Ch. 1 - 1.71 The thermal conductivity of silver at 212°F...Ch. 1 - 1.72 An ice chest (see sketch) is to constructed...Ch. 1 - Estimate the R-values for a 5-cm-thick fiberglass...Ch. 1 - A manufacturer in the United States wants to sell...Ch. 1 - Referring to Problem 1.74, how many kilograms of...Ch. 1 - 1.76 Explain a fundamental characteristic that...Ch. 1 - 1.77 Explain each in your own words. (a) What is...Ch. 1 - What are the important modes of heat transfer for...Ch. 1 - 1.79 Consider the cooling of (a) a personal...Ch. 1 - Describe and compare the modes of heat loss...Ch. 1 - A person wearing a heavy parka is standing in a...Ch. 1 - Discuss the modes of heat transfer that determine...
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
- A pipe in a manufacturing plant is transporting superheated vapor at a mass flow rate of 0.3 kg/s. The pipe is 10 m long and has an inner diameter of 5 cm and a wall thickness of 6 mm. The pipe has a thermal conductivity of 17 W/m·K, and the inner pipe surface is at a uniform temperature of 120°C. The temperature drop between the inlet and exit of the pipe is 7°C, and the constant pressure specific heat of vapor is 2190 J/kg·°C. If the air temperature in the manufacturing plant is 25°C, determine the heat transfer coefficient as a result of convection between the outer pipe surface and the surrounding air.arrow_forwardThe exhaust gases of an automotive engine leave the combustion chamber and enter a 8-ft-long and 3.5-in-diameter thin-walled steel exhaust pipe at 800°F and 15.5 psia at a rate of 0.05 lbm/s. The surrounding ambient air is at a temperature of 80°F, and the heat transfer coefficient on the outer surface of the exhaust pipe is 3 Btu/h?ft2?°F. Assuming the exhaust gases to have the properties of air, determine (a) the velocity of the exhaust gases at the inlet of the exhaust pipe and (b) the temperature at which the exhaust gases will leave the pipe and enter the air.arrow_forwardA pipe in a manufacturing plant is transporting superheated vapor at a mass flow rate of 0.3 kg/s. The pipe is 10 m long, has an inner diameter of 5 cm and pipe wall thickness of 6 mm. The pipe has a thermal conductivity of 17 W/m.K, and the inner pipe surface is at a uniform temperature of 120 °C. The temperature drop between the inlet and the exit of the pipe is 7 °C, and the constant pressure specific heat of vapor is 2190 J/kg.°C. If the air temperature in the manufacturing plant is 25°C, determine the heat transfer coefficient as a result if convection between the outer pipe surface and the surrounding air. T(r) = 120°C Superheated Air, 25°C r2 vapor r1 0.3 kg/s L = 10 m Tin-Tout = 7°Carrow_forward
- In a dairy operation, milk at a flow rate of 0.25m3/hr and a cow-body temperature of 38.6°C must be chilled to a safe-to- store temperature of 13°C. Cold water at 2.2°C is available at a flow rate of 0.94m3/hr. The density and specific heat of milk are 1030 kg/m3 and 3860 J/kg.K, respectively. The density and specific heat of water is 1000 kg/m3 and 4187 J/kg.K. The chilling process is done by a double pipe counter-flow exchanger with an overall heat transfer coefficient U=1000 W/m2.K. The pipe of the heat exchanger has a 50-mm diameter with negligible thickness. Determine the pipe length L required. Select one: O a. 2.28 m O b. 4.28 m O c. 3.28 m O d. 1.28 marrow_forwardA 5 - m long section of an air heating system of a house passes through anunheated space in the basement, Figure 1. The cross section of the rectangularduct of the heating system is 20 cm x 25 cm. Hot air enters the duct at 100 KPaand 60 oC at an average velocity of 5 m/s. The temperature of the air in the ductdrops to 54 oC as a result of heat loss to the cooling space in the basement.Determine :a) The rate of heat loss from the air in the duct to the basement under steadyconditions. b) The cost of this heat loss per hour if the house is heated by a natural gasfurnace that has an efficiency of 80%, and the cost of the natural gas in thatarea is $1.6/therm (1 therm = 105,500KJ). Given data for air:CP = 1.007 KJ/Kg Karrow_forwardA 65 kg beef carcass (k-0.47 w/mk and a-0.13 x10-6 m/s) initially at a uniform temperature of 37 "C is to be cooled by refrigerated air at -10 oC flowing at a velocity of 1.2 ms. The average heat transfer coefficient between the carcass and the air is 22 W/m²K. Treating the carcass as a cylinder of diameter 24 cm and the height 1.4 m and disregarding heat transfer from the base and top surfaces, Determine how long it will take for the centre temperature of the carcass to drop to 4 °C b. Also, determine if any part of the carcass will freeze during this process Hava- air -10 °C 12m/s Sider E Beef JTCarrow_forward
- A computer room located on the second floor of a five-story office building is 10m by 7 m. The exterior wall is 3.5 m high and 10 m long; it is a metal curtain wall (steel backed with 10 mm of insulating board), 75 mm of glass-fiber insulation, and 16 mm of gypsum board. Single-glazed windows make up 30 percent of the exterior wall. The computer and lights in the room operate 24 h/d and have a combined heat release to the space of 2 kw. The indoor temperature is 20 C. (a) If the building is located in Columbus, Ohio, determine the heating load at winter design conditions. (b) What would be the load if the windows were double-glazed?arrow_forwardConsider water (at a temperature of 276 K ) flowing inside a cylindrical pipe, having a diameter of 0.1 m and a thin wall. Under specific circumstances, temperature at the wall of the pipe reaches 258 K that helps form a layer of ice on the inner side of the wall of the pipe. Temperature and convection heat transfer coefficient at the inner surface of the ice layer are 273 K and 1500m2⋅Kw, respectively. Determine how thick the ice layer should be?arrow_forwardDetermine the length of the pipe required to cool the pasteurized orange juice from 65 to 22 °C at a rate of 1500 kg/hr in a 3 cm diameter pipe . The stream of chilled water is flowing from 4 to 20 °C, against the direction of the orange juice. The overall coefficient of heat transfer from the water to the orange juice is 900 J/m2s °C and the specific heat of the orange juice is is 3890 J/kg °C .arrow_forward
- Q2/A stainless steel ball (p 8055 kg/m3, Cp- 480 J/kg C) of diameter D 15 cm is removed from the oven at a uniform temperature of 350°C. The ball is then subjected to the flow of air at 1 atm pressure and 30°C with a velocity of 6 m/s. The surface temperature of the ball eventually drops to 250°C. Determine the average convection heat transfer coefficient during this cooling process and estimate how long this process has taken. Ans =23.75 minarrow_forwardWater is to be heated from 15°C to 65°C as it flows through a 3-cm-internal-diameter 5-m-long tube. The tube is equipped with an electric resistance heater that provides uniform heating throughout the surface of the tube. The outer surface of the heater is well insulated, so in steady operation, all the heat generated in the heater is transferred to the water in the tube. If the system is to provide hot water at a rate of 10 L/min, determine the power rating of the resistance heater. Also estimate the inner surface temperature of the tube at the exitarrow_forwardThe hot water needs of a household are to be met by heating water at 15°C to 95°C by a parabolic solar collector at a rate of 1.8 kg/s. Water flows through a 4-cm-diameter thin aluminum tube whose outer surface is blackanodized in order to maximize its solar absorption ability. The centerline of the tube coincides with the focal line of the collector, and a glass sleeve is placed outside the tube to minimize the heat losses. If solar energy is transferred to water at a net rate of 200 W per meter length of the tube, determine the required length of the parabolic collector to meet the hot water requirements of this house. Also, determine the surface temperature of the tube at the exit.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