Design method for steam exhaust connecting pipe of industrial steam turbine

The invention relates to the technical field of steam turbines, in particular to a design method of a steam exhaust connecting pipe of an industrial steam turbine; the steam exhaust connecting pipe is of a tubular structure for connecting an exhaust cylinder of the steam turbine and a condensing turbine, and the steam exhaust connecting pipe comprises a flange, a protection rod, a bellow expansion joint and a reinforcing rib; the design method comprises an arrangement position design method, a numerical simulation design method, an expansion joint design method and a calculation check design method. The length and the type of a steam exhaust connecting pipe is determined according to the arrangement positions of the steam turbine and the condensing engine; during numerical simulation, thermal displacement of the exhaust cylinder and the condensing engine and the actual working temperature of the exhaust steam connecting pipe serve as boundary conditions and are applied to the numerical model; a bellow expansi