| Popis: |
Great efforts are currently being made to increase the efficiency of power systems. From this point of view, cogeneration units are becoming more popular as they can convert the energy in primary sources with relatively high efficiency. However, there is always the effort to use even more energy from the primary sources, i.e. to decrease the energy losses. One of the means for achieving this is to cool down the flue gas to the lowest possible temperature and then use the heated cooling medium out of the unit. Heat transfer takes place in a tubular heat exchanger of a flue gas/water type, which is located behind the engine of the cogeneration unit. This paper deals with numerical simulations of fluid flow and heat transfer in this type of exchanger. Firstly, we present the fluid flow and heat analysis of a design with partitions. The geometry of the heat exchanger is described as well as the computational model and simulation setup. In total, three configurations of flue gas pipe and the recuperation flue gas/water are simulated to find out the influence of the external conditions on the exchanger performance. Finally, there is an overall comparison of the simulations. All the simulations are steady-state and were done in commercial software ANSYS CFX 17.0. |
