Foam has an especially large inter-phase contact surface which allows using it as a coolant. Characteristics of one type of foam -statically stable foamdemonstrated its perfect availability for this purpose. Our previous investigations of heat transfer processes in statically stable foam flow showed that large heat transfer intensity may be reached at a small mass flow rate of the foam. Statically stable foam flow is the two-phase system that has number of peculiarities: drainage of liquid from foam, diffusive gas transfer and destruction of inter-bubble films. Those phenomena are closely linked with each other and make extremely complicated an application of analytic methods for the study of heat transfer in foam. Thus experimental method of investigation was selected in our work. Experimental investigation of the heat transfer process from the in-line tube bundle to the vertical statically stable foam flow was performed. Dependency of heat transfer intensity on flow parameters and on tube position in the bundle was determined. The results of the experimental investigation are presented in this paper.

An experimental investigation of heat transfer from the tubes to the two-phase foam system was performed. Statically stable gas-liquid foam flow was used as a coolant. An investigation was performed on the experimental laboratory set-up consisting of the foam generator, an experimental channel and tube bundles. Two different geometries of in-line tube bundles were used for the experiments. Regularities of heat transfer of the tube bundles to the foam flow under the 180˚ degree turn were analysed in the work. The results of the investigation showed that heat transfer intensity is much higher than that for the one-phase airflow under the same conditions. The heat transfer character of frontal and further tubes to downward foam flow is different in comparison with the one-phase coolant flow. After the turn, local void fraction of the foam is less on the inner side of the foam flow. Therefore heat transfer intensity of the inner side-line tubes is higher than for other tubes of the bundle. The results of the investigation were generalized by criterion equations, which can be used for the calculation and design of the statically stable gas-liquid foam heat exchangers with the in-line tube bundles.

Gas-liquid foam due to especially large inter-phase contact surface can be used as a coolant. An experimental investigation of the staggered and in-line tube bundles’ heat transfer to the vertically upward and downward laminar foam flow was performed. The experimental setup consisted of the foam generator, vertical experimental channel, tube bundles, measurement instrumentation and auxiliary equipment. It was determined dependency of heat transfer intensity on flow parameters: flow velocity, direction of flow, volumetric void fraction of foam and liquid drainage from foam. Apart of this, influence of tube position in the bundle to heat transfer was investigated. Foam flow structure, distribution of the foam’s local void fraction and flow velocity in cross-section of the channel were the main factors which influenced on heat transfer intensity of the different tubes. Experimental investigation showed that the heat transfer intensity of the frontal and further tubes of the bundles to vertical foam flow is different in comparison with one-phase fluid flow. The results of the experimental investigation are presented in this paper.

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