An Experimental and Theoretical Study of Transient Pressure Drop in Two-Phase Condensing Flows

This paper presents the results of an experimental and theoretical investigation of the pressure drop associated with transient two-phase condensing flows involving complete condensation. Utilizing the system mean void fraction model, and the similarity relationships associated with it, an analytical prediction of the transient pressure drop is possible, including a simplified closed-form version. The capability of the proposed theory is demonstrated by comparison with experimental measurements of the transient pressure drop in a horizontal tube condenser following an exponential-type change in the inlet mass flow rate. Good agreement is shown to exist between the predicted and experimental results.