Estimation of the Optimum Combination of Combined Power Systems with a Diesel Engine by means of numerical Simulation

本文研究了柴油机、燃气轮机、热交换器等动力系统最优组合的数值预测方法。为了提高柴油机的性能，对发动机的最佳部件进行了估计研究。所得结果如下：1. 一个用于预测联电系统性能的仿真程序已基本完成。该程序可以预测柴油机、涡轮增压器、燃气轮机、后燃烧器、热交换器等的最佳组合，以提高联合动力系统的总热效率，尽管该程序的实用性还有待于与实验结果的比较来证实。提出了一种简单地将压气机或涡轮视为等效节气门面积的方法。这个等效面积可以用作评估参数，因为它不受发动机转速的影响。此外，还提出了一种新的涡轮增压系统——两台涡轮和一台压气机安装在一个共同的轴上，两台涡轮之间安装一个废闸阀。该2TIC涡轮增压发动机在瞬态和稳态工况下均表现出良好的性能。开发了一个实用的进气道三维非定常气流计算程序。

Methods for numerically predicting the optimum combinations have been investigated for the power systems, in which diesel engines, gas turbines, heat exchangers and others are included. Also studies have been carried out for estimating the optimum engine components in order to improve the performance of diesel engines. The results obtained are as follows. 1. A simulation program for predicting the performance of combined power systems has been nearly completed. This program can predict the optimum combinations of a diesel engine, turbochargers, gas turbines, after burners, heat exchangers and others to improve the total thermal efficiency of combined power systems, although the usefulness of the program is yet to be confirmed through the comparison with the experimental results.2. A method which treats simply the compressor or the turbine of turbocharters as an equivalent throttle area has been suggested. This equivalent area can use as an evaluating parameter, since it is not affected by engine speed. Furthermore a new turbocharging system - two turbine and one compressor are mounted on a common shaft and a waste gate valve is equipped between two turbines - is suggested. This 2TIC turbocharged engine shows suitable performances for transient and steady states.3. A practical program for calculating the three-dimensional unsteady gas flows in intake ports has been developed.