THE DYNAMICS OF BUBBLERS AS VAPOR DELIVERY SYSTEMS

The dynamic response of a bubbler to changes in operating conditions is explored with a mathematical model that accounts for the thermal capacitance of the temperature control system. We show that three key dimensionless parameters control the performance of the system, and we indicate how experiments can be performed to determine these coefficients. Special attention is given to the factors that affect the heat transfer resistance between the external heater and the agitated liquid in the bubbler. Data are presented for heat transfer coefficients in a commercial bubbler operating under typical conditions, and the relative roles of convection generated by the action of the bubbles, buoyancy-driven convection, and internal heat conduction, are described.