Flow Field And Structure Analysis On Low Pressure Cylinder Exhaust Pipe Of 1000MW Direct Air Cooling Steam Turbine Set

Electric power, the basic of modern industry, plays an important role in national economy. It's significant to research the power plant set and its components. Plenty of water is needed for the power plant cycle. To save the water resources, the power plants attach great importance to the use of direct air cooling steam turbine sets in northern China. The air condenser of 1000MW direct air cooling steam turbine set is laid out of the workshop, and the steam is directly led to the outside air condenser through the exhaust pipe. In this paper, the analysis for the capability of through flow of exhaust pipe and the structure of it is carried out. Thus, designers can regard the above calculating results as a reference to select proper liquid parameters condition, improve the structure of model, and judge the stability under loading, and so on.Firstly, by using the FLUENT software, the paper carries out a three-dimensional calculation on the steam flow field in the exhaust pipe, getting to know the flow field distribution, the coefficient of drag and the loss of pressure. The velocity of flow in some situation also will come to a result. The impede effect that the inner stay pipes to the flowing steam is researched according to the aerodynamics. The refluence in the low pressure area is analyzed and some improved measures, such as rebuilding the original conformation of the exhaust pipe, or adding some new guide plates inside the pipe, will be introduced to enhance the capability of through flow of exhaust pipe in many different flow conditions.Secondly, by using the ANSYS software, the structure of the exhaust pipe is analyzed and modeled according to the basic design project of it. The structure of the exhaust pipe is calculated to analyze the stress and strain of the exhaust pipe under the gravity, the pressure difference between the atmospheric pressure and inner partial vacuum, the force and the moment of force at the jaw of the external exhaust pipe. The paper then checks whether the stress and strain is adapted to the allowable stress and deformation of the materials and the structure, making some improvement on the large deformation and stress areas. And then, the paper analyzes the counterforce and countermoment of restriction components to see if it would affect the stability of structure. Lastly, a simple thermal model is used to analyze the thermal expansibility of the exhaust pipe to know whether the deformation ratio exceed the allowable deformation. The result of the structural calculation would be a reference to the structure improvement and the evaluation of the exhaust pipe's service life.The research of the paper offer some constructive ideas to the design and normal operation of the exhaust pipe of the direct air cooling turbine set. As for design, it could optimize the structure, improve the aerodynamics performance of the exhaust pipe, reduce the pressure losses, increase the economic benefit, avoid the damage of structure and enhance the security. And for the operation, it could make the set run smoothly, avoiding poor economy and security conditions under the instruction of the paper.