The possibility of obtaining fresh water from seawater has been known to mankind for thousands of years. The first modern desalination system were used 200 years ago on ship. Though many method have been proposed for desalting saline waters, only a few have been developed to a stage where they may be commercially used. The MSF process, which is the one most widely used, was developed by Professor Silver in the late 1950's. The most important factors effecting the design of MSF process is heat transfer phenomena.
In this study, we set up experimental apparatus which simulate heat recovery section of Multistage flash process. Heat transfer coefficient was determined by this apparatus. Experiments were carried out under various condition. Chamber is made of SUS304. The tube which flows cooling water is Cu-Ni alloy with a ratio of 9 to 1. Ceiling was made in triangular shape to prevent water from dripping to tube surface. To estimate tube surface temperature, k-type thermocouple was weldered outside of tube surface. Also, to measure the difference of cooling water temperature, k-type thermocouple was installed at both ends of tube.
In this experiment, heat transfer coefficient was decreased as flow rate of cooling water was increased. We found that heat transfer coefficient was decreased owing to exist of non-condensable gas. Also, increase of pressure induced decrease of heat transfer coefficient.
We simulated heat transfer phenomena using modified Nusselt's model. As a result, we found that the result of simulation showed agreement with the result of experiment.