Example 6.1. A horizontal steel pipe having a diameter of 50 mm is maintained at a temperatureof 50°C in a large room where the air and wall temperature are at 25°C. The heat is lost by freeconvection and radiation. The surface emissivity of the steel may be taken as 0.8. An estimate for theheat transfer coefficient for free convection with this geometry and air is 6.5 W/m² °C. Calculate thetotal heat lost by the pipe per unit length.

Given Diameter of steel pipe = 50mm Temperature of pipe surface = 50oC Room wall Temperature = 25…

Answered: Example 6.1. A horizontal steel pipe…

Introduction to Chemical Engineering Thermodynamics

8th Edition

ISBN:9781259696527

Author:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart

Publisher:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart

Chapter1: Introduction

Section: Chapter Questions

Problem 1.1P

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Similar questions

Estimate the natural convection heat transfer coefficient of the horizontal pipe. The outer surface temperature of the pipe is 120 °C. The ambient air temperature is 40 °C. The outer diameter of the pipe is 18 cm. Convection coefficient = W / m2 C.
Estimate the natural convection heat transfer coefficient of the horizontal pipe. The outer surface temperature of the pipe is 80 ° C. The ambient air temperature is 30 ° C. The outer diameter of the pipe is 10 cm. Convection coefficient = AnswerW / m² ° C.
Problem 2 The heat transfer through a particular wall has an overall heat transfer coefficient of 225 W m².°C with an overall ΔΤ = 200°C. One layer of the wall is stainless steel with a thermal conductivity of 18 W m.°C and a thickness of 3 mm. Calculate the change in temperature across the layer of stainless steel.
Air at 25 ° C blows over the hot steel plate whose surface temperature is maintained at 250 ° C. The plates are 50 cm x 40 cm in dimensions and 3 cm thick. The convection heat transfer coefficient on the upper surface is 30 W / (m? ° C). The thermal conductivity of steel is 45 W / (m ° C). Calculate the hourly heat loss from the plate surface. a. heat loss per hour = kJ. b. If the reverse side surface temperature is maintained, determine the hourly heat loss incurred = kJ.
A house has a composite wall made of wood, fiberglass insulation, and gypsum boards. On a cold winter day, the external and internal heat transfer coefficients are 60 and 30 W/m²°C, respectively. The total surface area is 350 m². (a) Determine the total heat loss through the wall: (b) if the wind were blowing strongly, increasing the external coefficient to 300 W/m²°C, determine the percentage increase in heat loss; (c) what is the thermal resistance determining the total heat flow through the wall?
1. A 5.2 cm diameter spherical ball whose surface is maintained at a temperature of 71°C is suspended in the middle of a room at 23°C. If the convection heat transfer coefficient is 15 W/m2 -°C and the emissivity of the surface is 0.8, determine the total heat transfer from the ball.
A glass window of width W = 1 m and height H = 2 m is 5 mm thick and has a thermal conductivity of k 1.4 W/m K. If the inner and outer surface temperatures of the glass are 15°C and -20°C, respectively, on a cold winter day, what is the rate of heat loss through the glass? To reduce heat loss through windows, it is cus- tomary to use a double pane construction in which adjoining panes are separated by an air space. If the spacing is 10 mm and the glass surfaces in contact with the air have temperatures of 10°C and -15°C, what is the rate of heat loss from a 1 m x 2 m window? The thermal conductivity of air is k, = 0.024 W/m.K.
A plane wall has a thermal conductivity of 20 W/(m-K) and generates heat at 0.5 MW/m3. The wall is 0.2 meters thick and is perfectly insulated on one side. The other side is exposed to fluid at 100 °C. The convective heat transfer coefficient between the wall and the fluid is 400 W/(m2 K). Determine the maximum temperature in the wall.
Estimate the natural convection heat transfer coefficient of the horizontal pipe. The temperature of the outer surface of the pipe is 120 ° C. The ambient air temperature is 25 ° C. The outer diameter of the pipe is 10 cm. Convection coefficient = Answer W / m² ° C.
A long homogeneous resistance wire of radius ro = 5 mm is being used to heat the air in a room by the passage of electric current. Heat is generated in the wire uniformly at a rate of 5 X 10' w/m as a result of resistance heating. If the temperature of the outer surface of the wire remains at 180°C, determine the temperature at r= 3.5 mm after steady operation conditions are reached. Take the thermal conductivity of the wire to be k = 8 W/m. °C. 180°C gen
) The inside surface of an insulation layer is maintained at 350oC and the outside surface dissipates heat by convection and radiation to air and wall, respectively. The temperatures of air and wall are 15 oC. The insulation layer has a thickness of 10 cm and a thermal conductivity of 15 W/m.K. What is the value of the heat transfer coefficient at the outside surface of the layer, if the temperature at the outside surface should not exceed 225 oC? (The emissivity and the width of the surface are 0.3 and 1 m., respectively. =5.67x10-8 W/m2K 4 ).
Please provide one-dimensional heat conduction equation in a large plane wall starting from energy balance for a system.

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