船用柴油机浸没式排气管冷却性能优化

Optimizing the Cooling Performance of Submerged Exhaust Pipe of Marine Diesel Engine

考虑到特殊船舶对柴油机排气温度要求严格,对柴油机浸没式排气管采用内展翅片形式以提高排气管的传热性能,采用数值模拟方法对浸没式内翅片排气管的流动、换热及阻力特性进行计算,将结果与实验关联式进行对比验证,比较不同翅片数目排气管的传热与流动性能,结果表明,采用内展翅片后,浸没式排气管的换热性能明显提高,努塞尔数为光管的1.2~2.0倍,阻力系数为光管的1.7~2.9倍,10翅、12翅浸没式排气管综合性能较优。

According to the strict requirements of diesel engine exhaust temperature for special ships,the heat transfer performance of the exhaust pipe was improved by using the form of internal expansion fins.By using the numerical simulation method,the flow,heat transfer and resistance characteristics of the submerged inner fin exhaust pipe were simulated and compared with the experimental correlation.The heat transfer and flow performance of exhaust pipes with different fin numbers were also compared.The results showed that the heat transfer performance of the submerged exhaust pipe is significantly improved by using the internally expanded fins,and the Nusselt number is 1.2~2 times of that of the smooth exhaust pipe,the resistance coefficient is 1.7~2.9 times of that of smooth tube.The comprehensive performance of the immersed exhaust pipe with 10 wings and 12 wings is better.