T. Zdankus

Influence of vertical foam flow liquid drainage on tube bundle heat transfer intensity

The results of an experimental investigation of staggered tube bundle heat transfer to upward and downward moving vertical foam flow are presented in this article. It was determined that a dependency exists between tube bundle heat transfer intensity on foam volumetric void fraction, foam flow velocity and direction, and liquid drainage from foam. In addition to this, the influence of tube position of the bundle on heat transfer was investigated. Experimental results were summarized by criterion equations, which can be applied in the design of foam type heat exchangers.

Different Type Tube Bundle Heat Transfer to Vertical Foam Flow

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.Copyright

Analysis of In-line Tube Bundle Heat Transfer to Vertical Foam Flow

Liquid or gas (single phase coolant) is widely used for heat removal in heat exchangers. Nevertheless usage of two-phase system (foam flow — particulary) as a coolant in some cases allows achieving better results: smaller coolant mass flow rate, relatively large heat transfer rate, low energy consumption required for coolant delivery to heat transfer place and etc.. An experimental study of the in-line tube bundle heat transfer to the vertically upward and downward after 180 degree turn laminar foam flow was performed. One type of gas-liquid foam-statically stable foam flow was used as a coolant during the experiments. It was determined dependence of heat transfer intensity on flow parameters: flow velocity, direction of flow, volumetric void fraction of foam and influence of liquid drainage from foam. Apart of this, influence of tube position of the bundle to heat transfer was investigated. Results of the investigation showed, that heat transfer intensity of the in-line tube bundle to the foam flow is much higher than to the one-phase airflow under the same flow velocity. Heat transfer intensity of the frontal and further tubes to vertical foam flow is different in comparison with one-phase fluid flow.