A 10-cm diameter pipe is covered by 2 layers of lagging. The inside layer is 4 cm thick and has a coefficient of thermal conductivity of 0.08 W/m-K. The outside layer is 3cm thick and has a coefficient of thermal conductivity of 0.15 W/m-K. The steam main conveys steam a pressure of 1.7 MPa with 25 C superheat. The outside temperature of the lagging is 27 C. If the steam main is 30 m long, determine the interface temperature of the lagging and overall coefficient of heat transfer based on outside area.

A 10-cm diameter pipe is covered by 2 layers of lagging. The inside layer is 4 cm thick and has a coefficient of thermal conductivity of 0.08 W/m-K. The outside layer is 3cm thick and has a coefficient of thermal conductivity of 0.15 W/m-K. The steam main conveys steam a pressure of 1.7 MPa with 25 C superheat. The outside temperature of the lagging is 27 C. If the steam main is 30 m long, determine the interface temperature of the lagging and overall coefficient of heat transfer based on outside area.

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.

Chapter7: Forced Convection Inside Tubes And Ducts

Section: Chapter Questions

Problem 7.17P: Determine the rate of heat transfer per meter length to a light oil flowing through a 2.5-cm-ID,...

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Determine the rate of heat transfer per meter length to a light oil flowing through a 2.5-cm-ID, 60-cm-long copper tube at a velocity of 0.03 m/s. The oil enters the tube at 16C, and the tube is heated by steam condensing on its outer surface at atmospheric pressure with a heat transfer coefficient of 11.3 kW/m K. The properties of the oil at various temperatures are listed in the following table: Temperature, T(C) 15 30 40 65 100 (kg/m3) 912 912 896 880 864 c(kJ/kgK) 1.80 1.84 1.925 2.0 2.135 k(W/mK) 0.133 0.133 0.131 0.129 0.128 (kg/ms) 0.089 0.0414 0.023 0.00786 0.0033 Pr 1204 573 338 122 55
A 10 cm diameter pipe is covered by 2 layer of logging. the inside layer is 4 cm thick and has a coefficient of thermal conductivity of 0.08 w/m-k. the outside layer is 3 cm thick and has coefficient of thermal conductivity of 0.15 w/m-k. the steam main conveys steam a pressure of 1.7 mpa with 25 C superheat. the outside temperature of the lagging is 27 C. if the steam main is 30 m long, determine the interface temperature of the lagging and overall coefficient of heat transfer based on outside area.
Problem 3: Insulation To=1 Toowwww Steam Tx2 T₂ T3 www www R₁ R₁ R₂ www.T R₂ Steam at Tx1 = 320 °C flows in a cast iron pipe (k = 80 W/m. °C) whose inner and outer diameters are 5 cm = 0.05 m and D₂ = 5.5 cm = 0.055 m, respectively. The pipe is covered with 3-cm-thick glass wool insulation with k = 0.05 W/m. °C. Heat is lost to surroundings at T2 = 5 °C by natural convection and radiation, with a combined heat transfer coefficient of h₂ = 18 W/m². °C. Taking the heat transfer coefficient inside the pipe to be h₁ = 60 W/m². °C, determine the temperature drops across the pipe and the insulation. The determination is based on a unit length of the pipe (L = 1 m). Assumptions 1. Heat transfer is one-dimensional since there is no indication of any change with time. 2. Heat transfer is one-dimensional since there is thermal symmetry about the centreline and no variation in the axial direction. 3. Thermal conductivities are constant. 4. The thermal contact resistant at the interface is…
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