Estimation of critical thickness of insulation for regular polygon cross-section ducts/conductors

Abstract

In some areas, due to geometry or space constraints, the outer structures of ducts or conductors are non-circular or are of regular polygonal shape. Determination of critical thickness of insulation for these ducts or conductors is difficult. The critical thickness of insulation, in case of circular cross section duct depends on the thermal conductivity of the material and heat transfer coefficient surrounding the duct. Authors in this work have attempted to estimate the critical thickness of insulation in case of regular polygonal cross-section. It is attempted to determine the critical thickness, leading to maximum heat loss, in case of various polygonal cross section. In this work the authors have estimated a correction factor that can multiplied to the critical thickness if the conductor is circular in cross section. It is observed that correction factor goes on increasing as the number of sides goes on increasing. The proposed work is relevant to the heat transfer community. Wire and solar plate manufacturers will be directly benefited from the outcome of this project to improve their design.