Experimental study of water film flow on large vertical and inclined flat plate

• We performed film flow experiment on large flat plate, the data of which is rare.
• Some new empirical correlations of film flow on large scale plate are obtained.
• Three transition points which indicate different flow mechanism changes are found.

Free falling water film flow is widely applied in many industrial fields, including the PCCS (Passive Containment Cooling System) of the Generation Ⅲ nuclear power plant. This paper describes an experimental study of free falling water film flow on a vertical and an inclined flat plate (2 × 5 m and 0.4 × 5 m). A capacitance probe and high-speed camera were used to capture the characteristics of film flow with different Reynolds (50 ∼ 3600). Many statistical variables of the film flow are presented, such as film thickness, wave length, wave frequency, and wave velocity etc. The test data are also compared with Nusselt theory and some empirical correlations from other researches. The effect of Reynolds number and inclination of the plate on film flow are studied.Three transition points which indicate different flow mechanism changes are found by analyzing different statistical film flow variables. With the increase of Reynolds number, the solitary waves of film flow develop from low speed waves of high frequency and short wave length to high speed waves of low frequency and long wave length. Empirical correlations of δ¯, δmin, δmax, δsub, δp, Uwave of film flow on large flat plate are obtained. It could be applied to the safety analysis program for PCCS.