Numerical Investigation of Convection and Radiation Heat Loss Reduction between Two Finite Concentric Cylinders Using Radiation Shields

Abstract

Investigation of the radiation and natural convection heat losses from two finite concentric cylinders with radiation shields is performed numerically. The enclosure consists of two concentric cylinders with hotter inner cylinder and radiation shields with three different materials (aluminum, copper and steel) are inserted between the cylinders at different radial positions. The effects of physical properties (material), geometrical effects of radiation shields, inner cylinder temperature, and enclosure pressure on the heat losses have been investigated. The calculations were performed for two different inner temperatures as 473.15, and 673.15 K, and at two enclosure pressures of 0.2 and 1.0 atm. Results showed that the enclosure pressure and radiation shield emissivity together reduce the total heat loss from the inner cylinder.

Keywords

• free convection
• radiation
• finite cylinders
• radiation shields
• enclosure