Heat Transfer Through Gases at Low Pressures

Abstract

The purpose of this study is to determine experimentally the heat transfer between two parallel vertical plates. The space between the plates is filled with a gas at low pressure, and the boundaries of this gas layer are enclosed by a solid heat insulator. The variation of this heat transfer with pressure, temperature difference, type of gas, and thickness of the gas layer is determined. The experimental result is compared with both theoretical and empirical equations. This result is Helium: Nu = 8.0 Gr^0.04 (L/H)^0.75 10⁻² < Gr < 5 × 10³ h = 9.2 kP^0.080 1 < P < 760 mm Hg Air: Nu = 14.1 Gr^0.022 (L/H)^0.75 10⁻¹ < Gr < 5 × 10³ h = 17.1 kP^0.083 1 < P < 100 mm Hg Note: P in mm Hg, h/k in ft⁻¹