Special A-frame geometry of the air-cooled condenser cell and the complicated flow field at the exit of the axial flow fan bring on the air mal-distribution on the surface of the finned tube bundles and the deteriorat...Special A-frame geometry of the air-cooled condenser cell and the complicated flow field at the exit of the axial flow fan bring on the air mal-distribution on the surface of the finned tube bundles and the deteriorated thermo-flow performances of a condenser cell. It is of benefit to the design and operation optimization of the direct dry cooling system in a power plant to investigate the thermo-flow characteristics of the condenser cell and propose the flow leading measures of cooling air. On the basis of the representative configuration of the air-cooled condenser cell in a 600 MW direct dry cooling power plant, the computa- tional models of the air side fluid and heat flows are built, in which the actual fan blade geometric details are considered. Various flow field leading ways of cooling air are presented and the thermo-flow characteristics in the A-frame condenser cell and through the finned tube bundles are compared. Results show that the flow field leading measures can result in the increased volumetric flow rate and heat rejection, thus bringing on the improved performance of the condenser cell. The improvement of thermo-flow oerformances depends upon the geometric details of the flow guiding device.展开更多
The typical configuration adopted by air-cooled condenser(ACC) in coal-fired power generating unit is the wave finned flat tube. The development of boundary layer between wave fins along long axis of flat tube can sup...The typical configuration adopted by air-cooled condenser(ACC) in coal-fired power generating unit is the wave finned flat tube. The development of boundary layer between wave fins along long axis of flat tube can suppress the air-side heat transfer enhancement to a great extent. It has been proved that the serrated fins can enhance heat transfer obviously by breaking the development of boundary layer periodically. In the present study,the discontinuous short wave fin was introduced to the flat tube to enhance the air-side heat transfer of ACC. Two different types of arrangements,i.e. staggered and in-line for discontinuous short wave fins on the flat tube,were designed. By numerical simulation,the heat transfer and flow performances of short wave fins were studied under different arrangements(in-line,staggered) ,and the influences on heat transfer and flow characteristics of rows of short wave fin and interrupted distance between discontinuous short wave fins were revealed numerically. The results indicated that,compared with the original continuous wave fin,the discontinuous short wave fin effectively improved the air-side heat transfer of flat tube under the air flow velocities in the practical application of engineering. Moreover,the increment of pressure loss of air-side flow was restricted for the discontinuous short wave fins because of the reduction of contact areas between the air flow and fin surface.展开更多
基金supported by the National Basic Research Program of China (973 Program)(Grant No.2009CB219804)the National Scientific and Technical Supporting Program of China(Grant No.2011BAA04B02)
文摘Special A-frame geometry of the air-cooled condenser cell and the complicated flow field at the exit of the axial flow fan bring on the air mal-distribution on the surface of the finned tube bundles and the deteriorated thermo-flow performances of a condenser cell. It is of benefit to the design and operation optimization of the direct dry cooling system in a power plant to investigate the thermo-flow characteristics of the condenser cell and propose the flow leading measures of cooling air. On the basis of the representative configuration of the air-cooled condenser cell in a 600 MW direct dry cooling power plant, the computa- tional models of the air side fluid and heat flows are built, in which the actual fan blade geometric details are considered. Various flow field leading ways of cooling air are presented and the thermo-flow characteristics in the A-frame condenser cell and through the finned tube bundles are compared. Results show that the flow field leading measures can result in the increased volumetric flow rate and heat rejection, thus bringing on the improved performance of the condenser cell. The improvement of thermo-flow oerformances depends upon the geometric details of the flow guiding device.
基金supported by the National Basic Research Program of China ("973" Program) (Grant No.2009CB219804)
文摘The typical configuration adopted by air-cooled condenser(ACC) in coal-fired power generating unit is the wave finned flat tube. The development of boundary layer between wave fins along long axis of flat tube can suppress the air-side heat transfer enhancement to a great extent. It has been proved that the serrated fins can enhance heat transfer obviously by breaking the development of boundary layer periodically. In the present study,the discontinuous short wave fin was introduced to the flat tube to enhance the air-side heat transfer of ACC. Two different types of arrangements,i.e. staggered and in-line for discontinuous short wave fins on the flat tube,were designed. By numerical simulation,the heat transfer and flow performances of short wave fins were studied under different arrangements(in-line,staggered) ,and the influences on heat transfer and flow characteristics of rows of short wave fin and interrupted distance between discontinuous short wave fins were revealed numerically. The results indicated that,compared with the original continuous wave fin,the discontinuous short wave fin effectively improved the air-side heat transfer of flat tube under the air flow velocities in the practical application of engineering. Moreover,the increment of pressure loss of air-side flow was restricted for the discontinuous short wave fins because of the reduction of contact areas between the air flow and fin surface.
