Experimental Investigation Of Heat Transfer Capability Of Falling Film Evaporation In The Vertical Tube With Spring Inserts

The influence of falling film evaporation to the heat transfer capability by inserting spring into the vertical tube was studied, and the water was used as medium in this paper. Spring inserts with eight different parameters were used. The influence of difference in temperature, Reynolds number of film, vacuum degree and spring parameter to the heat transfer capability on the evaporation side was studied through the uniform wall temperature experiment, by the result, the heat transfer coefficient on the evaporation side can be improved by inserting spring with proper parameter. When the Reynolds number was between 4000 and 14000, and the heat transfer coefficient can be improved nearly 30 percents by inserting the fifth spring when the Reynolds number nearly was 12000. Based on the J C Chen double mechanisms superposition model, the experimental formula of the heat transfer coefficient on the evaporation side in the smooth tube was obtained. Considering the influence of spring to the falling film, the formula of heat transfer coefficient on the evaporation side in the vertical tube with spring inserts was obtained. The predicated heat transfer coefficient through this two formulas was finely accord with the experimental result, and the error was basically under 10%.