Gas - Steam Combined Cycle Hrsg Characteristics Analysis And Mathematical Modeling

The advantage of gas-steam combined cycle is the cascade utilization of chemical energy in the fuel. Gas-steam combined cycle has been developed and its application is becoming more and more extensive. It is because the gas-steam combined cycle has preferable energy conservation and environmental protection benefit and investment benefit. It can recovery more and more waster heat. And the heat recovery steam generator is the most important consist of energy-transfer facility of the gas-steam combined cycle. It is used coupling the heat-transfer in the cycle. It linked the gas turbine, at the same time, it linked gas-steam turbine too. But in the past, people put little attention in the studying of the heat recovery steam generator. Because of the cycle unit load and the condition temperature influence, the cycle did not work under the design condition, but worked under the off-design condition. It is very important to analysis and research the character under the off-design.This thesis based on the single-pressure and non-additionally heat recovery steam generator. The keypoint of this thesis is the analyzing of the heat recovery steam generator's character under the off-design condition. And the mathematical model was built up. The thesis are composed the next four parts.First of all, the research background of this paper had been introduced, then analysis the prospects of the cycle unit in China. And the heat recovery steam generator as the important heat-transfer facility, it is very important in the cycle unit improvement. Then the paper introduced its development status at home and abroad. After it, the signification of builtting up its mathematical model was introduced.At second, the fundamental theory of the gas-steam combined is introduced in short page.It is consist of the working principle of the gas-steam combined cycle,the classification and composition and the three typical programmes of the HRSG. And the merits and demerits of three typical programmes of the HRSG are compared.Then,the energy equalization and heat-transfer relation of the HRSG are deduced.The next, it used the most of the paper to introduce the HRSG, the important parameters of the HRSG area nalysised.Then,some new thermal characters of the HRSG are nalysised during its development,especially the dynamic character of the HRSG under the off-design condition.At last, the mathematical model of the HRSG were built up on the basis of fundamental physical laws, first the HRSG system was broken up to two part, the fume part and the steam-water part. And in the steam-water part, it was broken up to the single-phase part and the evaporating-zone part, at last the evaporating zone part was broken up to four parts, including the boiler barrel part, the riser-pipe part, the down-pipe part and the water-cooling metal part. Their mathematical models were built up. And the mathematic analysis method also had beenintoduced. In the end it is given the numerical simulation of the mathematical model of the HRSG cases to prove the appropriate and correct of the mathematical model of the HRSG.