Heat Transfer during Vessel Discharge: Mean and Fluctuating Gas Temperature

Abstract

A gas, discharging from its container through an orifice to the atmosphere, is shown to experience a temperature history that is strongly dependent upon the heat transfer from the container wall. Using a quasi-steady free-convection model for the instantaneous conductance between the wall and gas, a satisfactory correlation results between experimental and analytical mean gas-temperature response during discharge. For the special case of choked orifice flow and constant wall temperature, the mean temporal temperature of the gas remaining within the vessel is shown to depend upon just two parameters. The onset of the oscillating component of gas temperature is shown to occur at times which correspond to the dramatic growth of the diffusional thermal boundary layer on the wall, and this finding is in agreement with the Malkus theory of turbulence. The relative size of the temperature oscillations during discharge is shown to reach a maximum at the time when the scale of dimensionless temperature, a parameter essentially dependent on the instantaneous mean gas temperature, is a maximum.