Numerical modelling of the operation of a two-phase thermosyphon

In the recent years, the interest towards the application of two-phase thermosyphons as an element of heat recovery systems has significantly increased. The application of thermosyphons is steadily gaining popularity in a wide range of industries and energy solutions. In the present study, a 2-D numerical modelling of a two-phase gas/liquid flow and the simultaneously ongoing processes of evaporation and condensation in a thermosyphon is presented. The technique volume of fluid was used for the modelling of the interaction between the liquid and gas phases. The operation of a finned tubes thermosyphon was studied at several typical operating modes. A parametric study over a non-ribbed and finned tubes thermosyphon was carried out. The commercial software ANSYS FLUENT 14.0 was used for the numerical analysis. It was proven that the numerical modelling procedure adequately recreates the ongoing flow, heat and mass transfer processes in the thermosyphon. The numerical result from the phase interaction in the thermosyphon was visualized. Otherwise, such visualization is difficult to achieve when only using empirical models or laboratory experiments. In conclusion, it is shown that numerical modelling is a useful tool for studying and better understanding of the phase changes and heat and mass transfer in a thermosyphon operation

Numerical modelling of a heat exchanger with thermosiphons

A mathematical model of the ongoing processes in a heat exchanger with heat pipes has been developed. The heat carrier is flue gas and the heated fluid is water. The numerical modelling is carried out by the CFD software SolidWorks – Flow Simulation. The obtained numerical results present the temperature and velocity fields in the heat exchanger. The influence of the heat exchanger’s design parameters over the temperature and velocity of the heated fluid are investigated. The modelled heat exchange has finned tubes thermosiphons in the evaporator zone and smooth tubes in the condensation zone. An analysis of the significant design parameters of the finned tubes over the heated fluid is carried out

Numerical modelling of a heat exchanger with heat tubes and experimental validation

On the basis of the developed mathematical model describing the ongoing processes in a heat exchanger with heat pipes a numerical modelling is carried out in order to obtain the temperature and velocity fields of the heat carrier and the heated fluid. In the present study the heat carrier is flue gas and the heated fluid is water. The numerical modelling is carried out by the commercial CFD software SolidWorks – Flow Simulation. Numerical results regarding the heat pipes pattern – corridor and staggered, have been obtained. The obtained numerical results were compared with experimental data collected from an operating heat exchanger with finned tubes thermosiphons. A good agreement between the numerical and experimental results is observed

Energy efficiency of large industrial facilities

The improvement of the energy efficiency is one the Bulgarian’s Government main priorities. The energy efficiency control, evaluation and improvement is under the jurisdiction of the state agency SEDA (Sustainable Energy Development Agency). SEDA is providing the industry with favorable development conditions resulting in increase of the competitiveness of the industrial companies and overall insuring a stable national economic. The improvement of the energy efficiency also has a significant effect over the reduction of the emitted greenhouse gases