Study On Simulation And Experiment Of CODAG Power Plant

The combined diesel and gas turbine power propulsion mode is the key one of main propulsion modes of the large and middle war ships. The CODAG has the economic advantage of CODOG power plant at cruise speeds and is able to use the diesel power together at higher ship speeds instead of the diesel being "dead weight". In recent years the power of diesel engine was increased very much because of using the sequence supercharging technology and the ratio of diesel power and gas turbine power was increased largely, from 20% to 61%, so that the top speed gain of the war ship will be 17% higher than the top speed by using only the gas turbine engine. The initial cost of CODAG plant is 79%~83% of initial cost of CODOG plant. The fuel consumption is only 80% of that of CODOG plant. The maintenance cost is only 35%~75% of that of CODOG plant. The top speed of the war ship is about 32 knots. Because the CODAG plant has many outstanding performances it is very important to investigate application characteristics of this kind of power plants and to master its key technology.By using experimental and simulation measures the operation performance control arithmetic and strategies of CODAG system were studied. Firstly the original CODOG experimental rig was revised to meet the requirements of test researches which are necessary for different modes of combined diesel and gas turbine power plant (CODOG or CODAG). Secondly the mathematical models of this experimental rig were established and relative operation simulation researches were worked out. The main results are as followings.1. The systematic analysis of operation modes of CODAG power plant was completed. Design manufacture installation and adjustment of hardware and software of measuring and controlling systems of CODAG experimental rig were completed also. Various experimental researches of CODAG system were conducted. Individual stable operation changeover and running together of the tow main engines were realized first at China. The experimental researches of load increase and decrease speed adjustment and speed step respond of tow engines running together were conducted. The speeds and power outputs of diesel and gas turbine were obtained and the displacements time curves of middle sliders of SSS clutches were obtained at various operation modes.2. Blocking decomposing of CODAG propulsion system was completed. The nonlinear models for analyzing control system were obtained. Steady and transient performances of the experimental rig were investigated by using computer digital simulation methods. MATLAB/Simulink simulation tools were used for the modeling and simulation of physical experimental rig of CODAG plant. By using the method from top to bottom and by using blocking modeling was completed. The models of the diesel and its electronic governor, the model of hydraulic coupling, model of control system of gas turbine, model of SSS clutch, model of running together gear box and model of load were included. Organic interaction integration was formed by using inlet and exit interfaces of the each sub-systems. Synthetic simulation researches on dynamic performances of the whole system were conducted and were compared with experimental results. Those researches provided useful references for control system design.Through a large number of experimental researches on the whole system the design of measuring and control system was proved to be a sound one and to be able to meet the requirements, the important theoretical and experimental bases were provided for the reliability and maneuverability of CODAG system.