QUESTION 6 The surfaces of a 0.2m thick glass wall are kept at temperatures 20°C and -10°c, respectively. If the wall is 1m high by 2m long, and the thermal conductivity is 0.8 W/mK, what is the rate of heat flow across it? O a. 250 W O b. 175 W O c. 48 W O d. 2500 W O e. 240 W O f. None of them

QUESTION 6 The surfaces of a 0.2m thick glass wall are kept at temperatures 20°C and -10°c, respectively. If the wall is 1m high by 2m long, and the thermal conductivity is 0.8 W/mK, what is the rate of heat flow across it? O a. 250 W O b. 175 W O c. 48 W O d. 2500 W O e. 240 W O f. None of them

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.37P: 1.37 Mild steel nails were driven through a solid wood wall consisting of two layers, each 2.5-cm...

See similar textbooks

Related questions

Q: If you know that the coefficient of thermal conductivity from the air to the inner surface of the…

A: Given,

Q: Explain, with annotated diagrams, the different effects of insulation and thermal mass on the heat…

A: A case study of Al Mafraq city in Jordan can be used to understand the varying impacts of insulation…

Q: Select all of the mechanisms of heat transfer that contribute to the fact that heat is extracted…

A: When a body is submerged in liquid water, the predominant mode of heat transfer is convection.

Q: Briefly explain the following. a) The effect of cross-sectional area and thermal conductivity on…

A: **According to guide-lines only three sub-parts can be answered at a time, please resubmit the…

Q: Hot roof is one of the causes that contributed to the rise of temperature of indoor spaces in…

A: Hot roof is one of the major reasons on increased heat absorbtion and less albedo of the sun…

Q: A furnace wall comprises three layers of thickness 250 mm, 100 mm, and 150 mm with thermal…

Q: 1. In summer, the owner of a house-made only of brick walls wants to know the heating transmitting…

Q: How long should an aluminum fin be in order to dissipate 90% of the heat that an infinitely long fin…

Q: A dormitory at a large university, built 50 years ago, has exterior walls constructed of L, =…

Q: A brick wall, 225 mm thick and having a thermal conductivity of 0.60 WI(m K), measures 10 m long by…

Q: A food cold storage room is to be constructed of an inner layer of 19.1 mm of pine wood, a middle…

Q: Mr. Bane is observing a protrude fin with a thickness of 0.0295 inches with a thermal conductivity…

Q: A dormitory at a large university, built 50 years ago, has exterior walls constructed of L, =…

A: Answer: (a) The heat flux through the original walls is 75.51 W/m2. (b) The heat flux through the…

Q: A spherical furnace has an inside diameter of 6 ft and ar outside diameter of 8 ft. The furnace…

Q: A cylindrical steel tank with a diameter of 3 m and height of 4.4 m is used to store chilled water…

A: Given: r = d/2 = 3/2 = 1.5 m H = 4.4 m h = 15 W/m2K

Q: What is the effect of change in the outer radius of the hollow cylinder on the thermal resistance of…

A: The formula for the thermal resistance of conduction in a hollow cylinder is, Rcond=12πkllnr2r1…

Q: 8. The wall of a cold storage room is composed of brick, concrete and cork insulation with thickness…

Q: Q2/ An insulated steam pipe having an outside Steam pipe diameter of 30 mm is to be covered with two…

A: Given Thermal conductivity(k1)=5k2 T1 and T2 are fixed Thickness = 20mm=0.02m Outside…

Q: A furnace wall comprises three layers of thickness 250 mm, 100 mm, and 150 mm with thermal…

Q: 1) Briefly explain the following. Why the temperature of heat conduction study bench should not…

A: Heat conduction is a medium of heat transfer in which the heat is transferred to the whole material…

Q: Please answer: Calculate the correct rate of heat loss through the vertical walls of a boiler…

A: Given that, Dimension of furnace wall, l×b×h=4×3×3 m3Thermal conductivity of inner brick, kb=0.4…

Q: 2. One side of a copper block 4 cm thick is maintained at 175-C. The other side is covered with a…

Q: Calculate the total resistance (in K/W ) through the vertical walls of a boiler furnace 20 m in…

A: Resistance R =L/KA total R = R1 + R2 + R3 Q = delta T / total R

Q: Insulating a heat transport system can be one of minimisation of heat loss.however addition of…

A: INTRODUCTION : If the wire is sufficiently thin, wrapping insulation over it may increase rather…

Q: what is 3 dimensional heat conduction?

A: Heat conduction in practice can be in any direction provided there is a temperature difference…

Q: To determine the thermal conductivity of a long, solid 2.5-cm-diameter rod, one half of the rod was…

Q: Identify the correct statement O a. The thermal resistance of conduction decreases with increase in…

A: Option C is the correct answer.

Q: Question 1.1: The inner and outer surfaces of a 5-m x 6-m brick wallof thickness 30 cm and thermal…

A: Outer temperature = 20C Inner diameter = 5C Area = 30 m2 Thickness = 30 cm thermal conductivity =…

Q: Bebang owns a 130-mm-thick concrete brick table top that has an area of 10,000,000 mm? and a…

Q: A pile of biomass (1.6 m deep, with a thermal conductivity of 0.41 W/mK) has been semi-buried in the…

A: Given : t = 1.6 m h = 13 W/m2K T = 23 C s = 15 W/m3 To find : Temperature at top surface at steady…

Q: A brick wall, plastered on one face, has a thermal conductance of 2.8 W/m^2-K, an inside surface…

A: Dear student, According to the guidelines I am allowed to answer only one…

Q: wall having a thermal conductivity of vity 0.9 W/mK. If the heat rate is to b

A: given:thermal conductivity of composite structural k=0.3W/mKthickness t=100mmhermal conductivity of…

Q: A furnace wall is constructed of an inner layer of 12.7 mm of refracter material, a middle layer of…

Q: Some help please (How do I go about this? TIA)...Determine the rate of heat loss per square foot…

A: The given values are - Area A=1 square foot, T1=70 F, T2=-10 FConverting F into °C→F-329=C5…

Q: furnace wall is constructed of a firebrick that is 6 inches thick. The temperature of the inside of…

A: Solution.jpg

Q: QUESTION 2 The wall of a refrigerated truck consists of 1.5mm sheet steel outer surface, 10mm…

Q: 12.3-2. Determination of Thermal Conductivity. In determining the thermal conductivity msu of an…

A: Given:

Q: The left side of a composite wall is kept at 300oC constantly. The right side of the same wall is…

A: Given thermal conductivity of KE =0.1 W/m K as mentioned ,which is very low as compared to other so…

Q: (i) What effect does the heat loss have on the value of heat transfer coefficie (ii) Is it important…

A: 1. Gas thermal conductivity increases with temperature in general, The reason for this is explained…

Q: 1.A carpenter builds an exterior house wall with a layer of wood 3.0 cm thick on the outside and a…

A: Given Data: The thickness of the wood, 3.0 cm The thickness of Styrofoam, 2.2 cm Thermal…

Q: ACTIVITY #3 - COMBINED CONDUCTION CONVECTION ON CYLINDRICAL WALL A hot-water pipe (k = 60 W/m K) in…

Q: In determining the thermal conductivity of an insulating material, the temperatures were measured on…

Q: A dormitory at a large university, built 50 years ago, has exterior walls constructed of L, =…

Q: What is the thermal resistance of a 3 in fired clay brick with density of 120 Ibm/ft3 a. 0.422 b.…

A: What is the thermal resistance of a 3 in fired clay brick with density of 120 lbm/ft3 a. 0.422 b.…

Q: 5.22 What is the thermal resistance of 12.1 cm (4 3/4 in.) thick precast concrete (stone aggregate,…

A: Thermal resistance R = L/K

Q: Briefly explain the following. 1.The effect of cross-sectional area and thermal conductivity on…

A: 1). The effect of cross-sectional area and thermal conductivity on conduction mode of heat…

Concept explainers

Conduction and Convection

When energy travels from one object to another it is said to have undergone heat transfer. Heat transfer is nothing but the transfer of thermal energy or internal energy from one thing to another, like e.g., when a vessel with water, kept on top of a burner, heats up because of the flame underneath it.

Question

Expert Solution

This question has been solved!

Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.

SEE SOLUTION Check out a sample Q&A here

Step 1

VIEW

Step 2

VIEW

Step by step

Solved in 2 steps with 2 images

SEE SOLUTION Check out a sample Q&A here

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

1.76 Explain a fundamental characteristic that differentiates conduction from convection and radiation.
1.51 The inner wall of a rocket motor combustion chamber receives by radiation from a gas at . The convection heat transfer coefficient between the gas and the wall is . If the inner wall of the combustion chamber is at Problem 1.51 a temperature of , determine (a) the total thermal resistance of a unit area of the wall in and (b) the heat flux. Also draw the thermal circuit.
A high-speed computer is located in a temperature-controlled room at 26C. When the machine is operating, its internal heat generation rate is estimated to be 800 W. The external surface temperature of the computer is to be maintained below 85C. The heat transfer coefficient for the surface of the computer is estimated to be 10W/m2K. What surface area would be necessary to assure safe operation of this machine? Comment on ways to reduce this area.
3.17 A 1.4-kg aluminum household iron has a 500-W heating element. The surface area is . The ambient temperature is 21°C, and the surface heat transfer coefficient is . How long after the iron is plugged in does its temperature reach 104°C?
Using Table 1.4 as a guide, prepare a similar table showing the orders of magnitude of the thermal resistances of a unit area for convection between a surface and various fluids.
1.4 To measure thermal conductivity, two similar 1-cm-thick specimens are placed in the apparatus shown in the accompanying sketch. Electric current is supplied to the guard heater, and a wattmeter shows that the power dissipation is 10 W. Thermocouples attached to the warmer and to the cooler surfaces show temperatures of 322 and 300 K, respectively. Calculate the thermal conductivity of the material at the mean temperature in W/m K. Problem 1.4
2.30 An electrical heater capable of generating 10,000 W is to be designed. The heating element is to be a stainless steel wire having an electrical resistivity of ohm-centimeter. The operating temperature of the stainless steel is to be no more than 1260°C. The heat transfer coefficient at the outer surface is expected to be no less than in a medium whose maximum temperature is 93°C. A transformer capable of delivering current at 9 and 12 V is available. Determine a suitable size for the wire, the current required, and discuss what effect a reduction in the heat transfer coefficient would have. (Hint: Demonstrate first that the temperature drop between the center and the surface of the wire is independent of the wire diameter, and determine its value.)
1.37 Mild steel nails were driven through a solid wood wall consisting of two layers, each 2.5-cm thick, for reinforcement. If the total cross-sectional area of the nails is 0.5% of the wall area, determine the unit thermal conductance of the composite wall and the percent of the total heat flow that passes through the nails when the temperature difference across the wall is 25°C. Neglect contact resistance between the wood layers.
One end of a 0.3-m-long steel rod is connected to a wall at 204C. The other end is connected to a wall that is maintained at 93C. Air is blown across the rod so that a heat transfer coefficient of 17W/m2 K is maintained over the entire surface. If the diameter of the rod is 5 cm and the temperature of the air is 38C, what is the net rate of heat loss to the air?
2.44 To determine the thermal conductivity of a long, solid 2.5-cm-diameter rod, one half of the rod was inserted into a furnace while the other half was projecting into air at . After steady state had been reached, the temperatures at two points 7.6 cm apart were measured and found to be and , respectively. The heat transfer coefficient over the surface of the rod exposed to the air was estimated to be 22.7 . What is thermal conductivity of the rod?
An electronic device that internally generates 600 mW of heat has a maximum permissible operating temperature of 70C. It is to be cooled in 25C air by attaching aluminum fins with a total surface area of 12cm2. The convection heat transfer coefficient between the fins and the air is 20W/m2K. Estimate the operating temperature when the fins are attached in such a way that (a) there is a contact resistance of approximately 50 K/W between the surface of the device and the fin array and (b) there is no contact resistance (in this case, the construction of the device is more expensive). Comment on the design options.
A boiler furnace wall must have a heat loss no greater than 700 Btu/hr~ft2 and is madeof a material with a thermal conductivity of 0.60 Btu/hr~ft~F. The inner wall surfacetemperature is '2000°F, and the outer surface temperature is 800°F. What wall thick~ness is required?