Analysis of heat transfer for critical thickness of insulation in a cylindrical pipe.For a circular pipe with length very large compared to outer diameter, it may be assumed that the heat flows only in radial radial /ra·di·al/ (ra´de-al) 1. pertaining to the radius of the arm or to the radial (lateral) aspect of the arm as opposed to the ulnar (medial) aspect; pertaining to a radius. 2. directions. If a layer of insulation installed around the circular pipe to reduce the amount of heat transfer, then it is assumed that the heat transfer will be decreased by adding more insulation. By adding the insulation around the pipe the outside surface area is increased, which will increase the heat transfer. This paper analyzes the critical thickness of an insulation-layer to minimize the heat transfer particularly in circular hot water pipes. For this the heat loss from an insulated in·su·late tr.v. in·su·lat·ed, in·su·lat·ing, in·su·lates 1. To cause to be in a detached or isolated position. See Synonyms at isolate. 2. pipe is considered as a function of the insulation thickness (t). The critical thickness (tc) is determined analytically in terms of thermal conductivity thermal conductivity A measure of the ability of a material to transfer heat. Given two surfaces on either side of the material with a temperature difference between them, the thermal conductivity is the heat energy transferred per unit time and per unit (k) of insulating material and the heat transfer coefficient The heat transfer coefficient is used in calculating the convection heat transfer between a moving fluid and a solid in thermodynamics. The heat transfer coefficient is often calculated from the Nusselt number (a dimensionless number). (h) of air. Using the spread sheet technique the critical thicknesses for various insulating materials are calculated. |
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