水下工作柴油机排气降温系统设计及试验

排气背压对柴油机的动力性能和油耗有着重要的影响,排气背压过大会造成动力性能的损失和油耗的增加,因此,在为柴油机设计排气后处理装置时,要充分考虑排气背压的大小。本文针对水下工作的柴油机,设计了一套排气降温系统,可以使得该柴油机在水下工作时,其排气可以被冷却后直接排向大气,并且其动力性能不受影响,这就要求在设计过程中要使整个排气降温系统的流动阻力尽可能最小。通过试验结果表明:加装该排气降温系统后柴油机输出动力性能良好,无功率和转矩损失;特殊管壳式换热器换热效果良好,能使最高温度为503.4℃的高温烟气降低到39.4℃。本文研究的结果对小型水下动力装置排气降温系统的选择和设计有一定的参考价值。

Design and Experiment on Exhaust Cooling System of Underwater Diesel Engine

Exhaust back pressure has a significant impact on the engine power performance and fuel consumption. Excessive exhaust back pressure may lead to the loss of power performance and increase fuel consumption. Therefore, the design of diesel exhaust after treatment device should consider the exhaust back pressure. In this paper, for the diesel engine that works underwater, a set of exhaust cooling system is designed, enabling cooling the exhaust from underwater operating engine before being discharged directly into atmosphere, but not affecting its dynamic performance. The exhaust cooling system should be designed possibly with a lowest flow resistance. The experimental results show that the diesel engine has good power performance after being equipped with the exhaust cooling system without losses of power and torque and that the special tube heat exchanger with good heat transfer performance decreases the high exhaust temperature from 503.4℃ to 39.4℃. This research results also provides a reference for the design of the exhaust cooling system for the small underwater power equipment.