【作者】 高阳；

【导师】 王银燕；

【作者基本信息】 哈尔滨工程大学 ， 轮机工程， 2013， 硕士

【摘要】 由于明显能够提高船舶运行时的能量利用率，对于大型船用低速二冲程柴油机排气余热利用已经越来越受到重视。但是由于目前二冲程柴油机的热效率较高，排出的排气温度较低，不利于对其中所含能量的利用，因此需要提高其排气温度，同时还不能使柴油机较高的经济性和动力性损失。本文将以MAN B&W6S50MC型低速二冲程柴油机为研究对象，研究如何在保证燃油消耗率升高不超过2%和最高燃烧压力不超过限值的前提下，将柴油机的排气温度提高到290°C以上,使得余热锅炉能够充分利用柴油机排气中的能量，从而提高整个船只的能量利用率。首先在详细分析6S50MC型柴油机主要结构以及低速二冲程柴油机特有的特点的基础上，在Matlab/Simulink仿真软件环境中，建立了该型柴油机的仿真模型。按照推进特性对该模型进行了验证计算，并将计算结果与试验数据进行了对比。结果证明，仿真结果与试验数据基本吻合，从而验证了所建立仿真模型的准确性。在所建立的仿真模型的基础上，分别通过调整柴油机和调整涡轮增压器对柴油机进行余热调制。在调整柴油机调制过程中，首先研究了改变改变喷油提前角、排气持续期以及排气旁通量对柴油机余热调制的影响。然后从计算结果中选出几组参数组合，并进行了仿真计算，得到了满足要求的结果。在调整涡轮增压器调制过程中，首先计算了柴油机各主要性能参数随喷嘴面积减小的变化。并在此基础上选定一个喷嘴面积并通过排气旁通对模型进行仿真计算，同样得到了满足余热调制要求的结果。根据船用柴油机的特点，对经过调制前后的6S50MC型柴油机进行了热平衡分析。并对经过调制后的柴油机在额定工况下，通过动力涡轮和余热锅炉所能产生的电量进行了估算。从分析和计算结果中证明了，通过对经过调制后柴油机进行余热利用，可以提高整个系统的能量利用率，减少燃油的消耗。更多还原

【Abstract】 Because of the significantly improvement on ship’s energy utilization while operating,waste heat utilization on large marine low-speed two-stroke diesel engine has drawn more andmore attention. But due to the high thermal efficiency, the exhaust gas temperature is low,which is not conductive to use the energy contained in exhaust gas, so the increasing of theexhaust temperature is necessary, while the loss on power and economy should be acceptable.In this paper, MAN B&W6S50MC large marine low-speed two-stroke diesel engine as theobject, study on increasing the exhaust gas temperature to more than290°C withoutincreasing fuel consumption no more than2%and the maximum combustion pressure notexceeding the limit, so the waste heat boiler could make full use of the energy in exhaust,thereby the energy utilization of the entire vessel could be improved.First, based on the detailed analysis on the main structure of the6S50MC diesel engineand specific characteristics of the low-speed two-stroke diesel engine, a simulation model isestablished in Matlab/Simulink environment. According to the propulsion characteristic, themodel is verified and the simulation results are compared to the experiment data. Comparisonresults verify the accuracy of the simulation model due to the consistent between simulationresults and the experiment data.Based on the simulation model, the waste heat of the engine is modulated by adjustingthe engine and the turbocharger. While modulateing by adjusting the engine, impacts onmodulation by changing the injection advance angle, the exhaust duration and exhaust gasbypass are studied. Some parameters are chosen from results, the model is simulated bycombinated these parameters, and the simulating results meet the requirements.In the process of modulating by adjusting the turbocharger, impacts on performance byreducing the nozzle area are simulated. A certain nozzle area is chosen based on the results,and by adding the bypass, the model is simulated, and the simulating results meet therequirements as well.On the basis of the characteristics of the marine diesel engine, a thermal equilibriumanalysis on original6S50MC diesel engine and the modulated engine is studied. And thegenerating capacity through power turbine and the waste heat boiler under the rated condition is estimated. The analysis and the calculation results shows that by applying waste heatutilization system to the modulated engine, energy utilization of the whole system could beincreased, and relatively the fuel consumption of the whole system is decreased.更多还原