CT-1 Pure Component Condensation Inside Horizontal and Inclined Tubes
This report documents the comprehensive HTRI study on condensation of pure components inside horizontal tubes. This study, based largely on new HTRI data, has been completed to the point of producing a practical, accurate calculation procedure which takes its place as the recommended method in the HTRI Design Manual and applicable computer programs.
A literature survey was also made including all available methods and data. No presently available correlations predict the entire range of available data well due to neglect of the important effects of flow regimes.
In this report the various condensation flow regimes are discussed and related to applicable mechanistic condensation models which produce the proper physical trends. The background and details of development of the HTRI Flow Regime Map are presented in HTRI Report CT-2. In addition to the basic flow regime parameters described there, a new parameter has been developed which locates the condensation path on the flow map and indicates immediately whether condensation will terminate in stratified flow or plug flow as the vapor fraction goes to zero. A generalized method is produced which uses a series of different correlations, selected on the basis of flow regime parameters, and which gives unequaled accuracy in predicting local average condensation heat transfer coefficients in horizontal and slightly inclined tubes. One new feature is the use of the Ohnesorge Number to predict the effect of entrainment on heat transfer in annular flow. The method is ideally suited to computer calculations, but can also be used by hand as demonstrated by a calculated example.