Simulation Study On Matched Performance Of Turbo-charger Units In Supercharged Boilers

Compared with other power devices, a supercharged boiler has a obvious advantage of larger power output, making it a common power source for large vessels. Being one of the key components of a supercharged boiler, turbo-charger units provide the chamber with high-density air utilizing the waste heat of boiler's exhaust air. It is required that modifications are made on the prototype to enhance the volume. According to theoretical analysis, the problems discussed above can be solved by adding stages to the compressor in turbo-charger units, which is also the main work done in this paper.A complete set of dynamic simulation models of the turbo-charger units are built in this paper on the basis of a series of rational simplifications and assumptions. The main work is as follows:1) Fast and accurate calculation models of working fluid's thermodynamic properties are built blending the programming methods of VC and MATLAB; 2) The simulation model of compressor's property was built by least square method and nueral network method; 3) On the basis of the models above, build the dynamic simulation models of the turbo-charger units using the method of object-oriented approach and obtain corresponding reactions of compressor's properties when the turbo-charger units are operating in off-design conditions,.Analysis about the influences of unit parameter by intake and exhaust resistance under rated condition was also made.Simulation results show that:1) If the air supply and the total caloric receptivity of boiler remain unchanged, compressor efficiency can be enhanced by reducing suction air resistance loss and boiler heat efficiency can be enhanced by reducing exhaust loss as well.2) The surge margin of compressor and boiler heat efficiency can be increased by reducing suction air resistance loss if auxiliary steam turbine doesn't work under variable condition; The surge margin of compressor and boiler heat efficiency can be increased if auxiliary steam turbine get involved.3) If auxiliary steam turbine doesn't work during the acceleration process, the time for boiler acceleraton and unit response should be long enough to assure the sufficient air supply. When using a reasonable control law to optimize auxiliary steam turbine. Not only can the required amount of air be guaranteed that compressor provide to boiler,but also to get a larger surge margin. By this time, the dynamic response time can be reduced as well.