Experimental Investigation Of Heat Transfer Character Of Vertical Tube Falling Film Evaporator With Spring Coil Inserted

The heat transfer in vertical tube falling film evaporator equipped with spring inserts is investigated the first time. All kinds of influence factors are analyzed after a larger number of experiments. Exerting the model of two mechanism heat transfer , the formulation for heat transfer coefficient of liquid film which in smooth tube and equipped with spring inserts is given in this paper. Heat transfer coefficient is presented which not only has relation to Reynolds number, temperature difference, liquid characteristic, but also is greatly influenced by structure parameter of the spring inserts. Experiments indicate the heat transfer coefficient of tubes equipped with spring inserts is 25% higher than smooth tube. Heat transfer will worsen if structure parameters of the spring inserts are not fit. The paper think that the mechanism of heat transfer enhances of the spring inserts is the laminar flow lining is thinner because of librating of the spring inserts, accordingly the part of convection is enhanced. But the part of boil is not influenced.