The objective of this research is to investigate large-scale transient flow surges of the condensate leaving in-tube condensing flow systems because of perturbations in the inlet vapor flow rate, and the influence of the subcooled liquid inertia of the condensate on these transient responses. Small changes in the inlet vapor flow rate momentarily cause large transient flow surges in the outlet liquid flow rate. Condensate inertia is seen to destabilize the system into an underdamped behavior where the flow rate can overshoot the final steady-state position several times. A one-dimensional, two-fluid, distributed parameter system mean void fraction (SMVF) model of the time-dependent distribution of liquid and vapor within the two-phase region is developed for predicting these transient characteristics, which it is seen to do quite well, especially when consideration is given to the complex nature of the problem.

Issue Section:
Technical Briefs
Keywords:
undercooling, condensation, two-phase flow, pipe flow, flow instability, two-phase, condensing, transient, heat transfer
Topics:
Flow (Dynamics), Inertia (Mechanics), Porosity, Subcooling, Surges, Transients (Dynamics), Unsteady flow, Vapors, Steady state
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