A Capstone Senior Design Project: Thermal Design of Insulated Pipes That Carry Hot Single-Phase Fluids and are Immersed in Atmospheric Air

Abstract

The accurate estimation of the insulation thickness of pipes carrying hot fluids may be achieved rapidly in an unprecedented manner articulating knowledge of courses on numerical methods and heat transfer. The aim of this paper on engineering education is to demonstrate that the algebraic solution of a lumped energy equation combined with an iterative solution of a nonlinear algebraic equation enables students to design insulation thicknesses of pipes carrying hot fluids with laminar or turbulent motion. The input data for the lumped energy equation consists of two parts. The internal part requires the use of the distribution of axial-mean internal Nusselt number for a thin-walled pipe with a prescribed surface temperature. The external part demands the use of the peripheral-mean external Nusselt number for a solid cylinder at a constant temperature. The allowable heat loss to the ambient air constitutes the primary design constraint in the thermal design project. The preliminary phase of such a project is covered in all text books on heat transfer from a simple and unrealistic idealization of one-dimensional conduction of heat, but has never been attempted for a realistic situation of two-dimensional convection of heat.