VM161

VM161
Heat Flow From an Insulated Pipe

Overview

Reference:	F. Kreith, Principles of Heat Transfer, 2nd Printing, International Textbook Co., Scranton, PA, 1959, pg. 36, ex. 2-7.
Analysis Type(s):	Thermal Analysis (ANTYPE = 0)
Element Type(s):	3D 20-Node Thermal Solid Elements (SOLID90)
Input Listing:	vm161.dat

Test Case

A pipe, covered with a layer of insulation, transports a fluid at a temperature T_i. For a given ambient air temperature T_o, determine the heat loss q across the outer surface per lineal foot of pipe.

Figure 226: Insulated Pipe Problem Sketch

Material Properties

Geometric Properties

k₁ = 25 Btu/hr-ft-°F

k₂ = 0.11 Btu/hr-ft-°F

h₁ = 40 Btu/hr-ft²-°F

h₂ = 4 Btu/hr-ft²-°F

r₁ = 1.535 in = 0.1279166 ft

r₂ = 1.75 in = 0.1458333 ft

r₃ = 2.25 in = 0.1875 ft

= 1 ft

T_i = 300°F

T_o = 80°F

Analysis Assumptions and Modeling Notes

An arbitrary 30° sector, of unit length , is used for the axisymmetric model.

Results Comparison

	Target	Mechanical APDL	Ratio
q, Btu/hr	362.0	362.0	1.000

Calculated from the surface heat flow rate of 30.17 x 360°/30°.