Theoretical investigation of conjugate condensation heat transfer inside vertical tubes

Köse, Serhat
Based on the well-known theoretical studies related to the film condensation inside vertical tubes, a known temperature distribution is prescribed as boundary condition at the inner surface of the tube wall. But, in reality, there is a thermal interaction between the condensate fluid and conduction through the wall where the temperature variation along the inner surface of the tube wall is unknown and this unknown temperature profile should be determined by taking account of this interaction. In other words, the heat conduction equation for the tube wall and the energy equation for the condensate fluid flow should be coupled and solved simultaneously. Therefore, this type of problem is named “conjugate condensation heat transfer problem”. Subject to the conjugate condensation heat transfer problem in the industrial applications, there are two different fluid flows separated by a tube where the vapor flowing inside the tube condensates whereas the other one is heated and it flows externally in the counter current direction in the annular passages. Because of its fundamental and practical importance, in this doctoral thesis, the studies are focused on the analytical and numerical investigation of conjugate heat transfer due to the steam condensation inside vertical tubes which is cooled externally by a fluid flowing in the counter current direction. The unknown wall temperatures of the condenser tube, condensate liquid layer inside the tube and the turbulent coolant flow outside the tube are coupled. A computer code, named ZEC, containing condensation conjugate heat transfer model is developed in FORTRAN 90 Language. This code and the models it contains are assessed against the various experimental databases. The predictions of the code ZEC are found to reasonably agree with the experimental results over a wide range of conditions. Therefore, this developed code, ZEC, may be used for the preliminary design of in-tube condensers and for the performance evaluation of such condensers in operation.


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Citation Formats
S. Köse, “Theoretical investigation of conjugate condensation heat transfer inside vertical tubes,” Ph.D. - Doctoral Program, Middle East Technical University, 2010.