.200 Mw Steam Turbine Condenser Heat Transfer And Flow Simulation And Heat Transfer Enhancement Engineered

The condensers of power unit, as one of the important auxiliary equipments of turbine, influence the safe economic operation of entire system. The low heat-exchange efficiency appears due to the irrational pipe-bundle arrangement, which influences the economic performance of power unit. Therefore, the enhanced heat-transfer research has the important theoretical significance and engineering value for application, in terms of the problems encountered on the condenser of 1# unit.The heat-transfer process of condensers mainly exists on the side of steam, however, the condensing heat transfer on the side of steam is the forced-convection one of steam-gas mixture which relates to the non-condensing gas, whose flow and heat-transfer performance severely vary along the cooling surface. The numerical simulation of steam flow field and heat transfer in condenser is necessary for the design, modification and operation of condenser. In this thesis, based on the mathematical physical model, the numerical simulation is carried out for the N-11220 condenser. The flow field, temperature field, and the distribution of air density and coefficient of heat transfer on the condenser with egg-shape pipe-bundle arrangement were discussed in detail, compared with those for the B-D modularization pipe-bundle arrangement. As far as the former arrangement was concerned, the unbalancedness of flow field appears. In addition, several vortexes happen, which result in the falling of the whole heat-transfer coefficient and cause the unfavorable cooling. Otherwise, the unsatisfactory cooling and suction result in the low vacuum of condensers. With the same space of tube layout, flow and temperature of recycled water, the flow field is balanced, the flow resistance of pipe bundle is lower, the pressure drop is smaller, the arrangement of heat load is uniform, the cooling effect in the air-cooling area is ideal comparably, and the condensate depression is low in terms of the B-D modularization pipe-bundle layout, which' lead to the advance of the whole heat-transfer performance.Based on the above theoretical analysis, the actual modification of condensers was carried out considering the feature of operation and water quality. By means of comparing the data of working parameters before and after the reform, the vacuum of condenser after the modification which is 2KPa especially for the optimal period, was...