We set up experimental apparatus which can obtain heat transfer conefficent during vapor condensation. This experimental appartus can simulate heat recovery section of multi-stage flash process. In this paper, overall and local heat transfer coefficient of plain tube has been measured based on temperature difference between cooling water in the tube and steam under various conditions.
Experiments were carried out in simplified single stage of heat recovery section of MSF. Chamber is made of stainless steel and the tube is Cu-Ni alloy with a ratio of 9 to 1. Thermal conductivity of tube material is 42w/m K. Ceiling was made in triangular shape to prevent water droplet from dripping to tube surface. k-type thermocouple was placed outer side of tube. View port was provided to enable observation of condensation on tube surface. To measure the overall heat transfer coefficient, we installed thermocouples at both ends of tube. To analyze the effect of flow rate and vapor pressure on local heat transfer coeffiecient we evaluated local heat transfer coefficient by varing the flow rate through the tube and the temperature and pressure inside the chamber.
The experiment was conducted under steady state. Pressure is kept under boiling point to give enough vapor to condensate on tube surface. The range of flow rate varied 1ℓ/min to 10ℓ/min. We examined local heat transfer coefficient with the change of vapor pressure.