THERMAL INSTABILITIES IN DISCHARGING GAS RESERVOIRS.

The flow structure in a discharging gas reservoir is studied using schlieren cinematography. Effects due to discharge orientation, gas species, and vessel wall vibration are observed. Initially, the internal flow structure is found to be controlled by the mass sink, with streamlines going in approximate straight lines from the vessel wall to the exit orifice. At later time, free convection dominates and recirculation patterns are established. Discharge orientation can have a dramatic effect on the free convection flow field as well as on the growth and stability of the wall thermal diffusion layer. A model for temperature variation in the thermal diffusion layer is discussed and a numerical solution is given. Results of the predicted thermal diffusion layer histories are compared to data. A discussion of vessel orientation effects on critical Rayleigh number is given.