Experimental and numerical investigation of two-phase pressure drop in vertical cross-flow over a horizontal tube bundle

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An experimental and numerical study of two-phase flow in a kettle reboiler

The purpose of this study is to investigate the two-phase flow in a kettle reboiler in order to improve the design methods used for them. An air-water in-line tube bundle was designed and constructed with tubes 38 mm in outside diameter on a pitch to diameter ratio of 1.32 to provide two phase pressure drop data. These data and other data from the literature were used to investigate the two-fluid model proposed by Simovic et al. [1] and the conventional 1-D design model, implemented with three separate void fraction correlations and one two-phase friction multiplier correlation. The results showed that the two-fluid model predicted air-water void fraction data well but R113 data poorly, with pressure drop predictions for both being unsatisfactory. The one-dimensional model was shown to predict pressure-drop and void fraction data reasonably well, provided the Feenstra et al. [2] correlation for void fraction and the Ishihara et al. [3] correlation for two-phase friction multiplier were used.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

A mechanistic analysis of shell-side two-phase flow in an idealised in-line tube bundle

This paper reports on an experimental study of air–water mixtures flowing through an idealised shell and tube, in-line heat exchanger. Void fraction measurements are reported for the minimum gaps between the tubes at near atmospheric conditions. The pressure distributions around some tubes are also reported. These data are combined with data available in the open literature to investigate pressure drop and void fraction prediction methods for these heat exchangers. The data are shown to be flow pattern dependent. Criteria for flow pattern boundaries are deduced from previously published flow maps. Void fraction data in the maximum gap between the tubes are shown to be compatible with the drift flux model and to be different in magnitude to the minimum gap values, which are shown to result from acceleration phenomena in the gaps between the tubes. The pressure drop data are analysed through a one-dimensional model that incorporates separation and re-attachment phenomena. The frictional pres-sure drop is shown to depend on a liquid layer located on the upper portion of the tubes at low gas veloc-ity and on acceleration effects at high gas velocity

A mechanistic analysis of shell-side two-phase flow in an idealised in-line tube bundle

This paper reports on an experimental study of air–water mixtures flowing through an idealised shell and tube, in-line heat exchanger. Void fraction measurements are reported for the minimum gaps between the tubes at near atmospheric conditions. The pressure distributions around some tubes are also reported. These data are combined with data available in the open literature to investigate pressure drop and void fraction prediction methods for these heat exchangers. The data are shown to be flow pattern dependent. Criteria for flow pattern boundaries are deduced from previously published flow maps. Void fraction data in the maximum gap between the tubes are shown to be compatible with the drift flux model and to be different in magnitude to the minimum gap values, which are shown to result from acceleration phenomena in the gaps between the tubes. The pressure drop data are analysed through a one-dimensional model that incorporates separation and re-attachment phenomena. The frictional pressure drop is shown to depend on a liquid layer located on the upper portion of the tubes at low gas velocity and on acceleration effects at high gas velocity