Flow Patterns During Condensation of Pure Refrigerants on Enhanced Tubes Under High Vapour Velocity
نویسندگان
چکیده
This work experimentally investigates the effect of vapour velocity during condensation of a ref rigerant on the outside of a single horizontal enhanced tube with particular reference to the fluid-dynamic mechanisms indu ced by vapour shear stress, surface tension and gravity on the condensate flow. More than 70 experimental runs were done in a transparent test section in order to directly o bserve the condensation of vapour, to take photographs and video-camera film, with two different extended tubes (an integ ral-fin tube with 1333 fins per meter and a commercial pin-fin type Hitachi Thermoexcel tube) in a wide operative range . These direct observations were implemented with the heat transfer coefficients previously measured by the authors with th e same test tubes under the same operative conditions.
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