Heat transfer characteristics of dropwise condensation of steam on vertical polymer coated plates

The plasma polymerization method and dynamic ion-beam mixed implantation me thod were employed to coat ultra-thin polymer films on copper plates. Exper iments indicated that steady dropwise condensation of steam at atmospheric pressure occurred. The condensation heat transfer coefficients increased by approximately 3 and 5-7 times for the polytrimethylvinylsilane film and po lytetrafluoroethylene film respectively, compared with the value for film c ondensation under the same experimental conditions. The temperatures on the condensing surface and inside the test block were found to be rapidly and randomly fluctuated. The properties of the coated films and advantages of t he methods used in this investigation were discussed briefly.