王松，蒋炎坤，宋昌，梁垚

华中科技大学能源与动力工程学院

    摘要：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中，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。

     关键词：水下工作; 排气降温系统; 管壳式换热器; 动力特性

    Abstract：Exhaust back pressure on the engine power performance and fuel consumption has a significant impact ,excessive exhaust back pressure caused by the loss of power performance and fuel consumption increases,Therefore, in the design of diesel exhaust aftertreatment device , the exhaust back pressure to fully consider the size .In this paper, the diesel engine underwater work , designed a set of exhaust cooling system, can make the engine work underwater , it can be cooled exhaust gas discharged directly to the atmosphere , and its dynamic performance is not affected, which requires in the design process to make the exhaust gas cooling system, the smallest possible flow resistance .Through experimental results show that : the installation of the exhaust gas cooling system engine power output , good performance, no loss of power and torque ; special shell and tube heat exchanger to good effect , can make a maximum temperature of 503.4℃ high temperature flue gas reduction to 39.4℃. The results of this study for small underwater power plant exhaust cooling system selection and design has a certain reference value.

     Keywords：underwater diesel engine;  exhaust cooling system;  tube shell heat exchange;  output dynamic