Han Jichao

Influence of the End Ventilation Structure Change on the Temperature Distribution in the End Region of Large Water–Hydrogen–Hydrogen Cooled Turbogenerator

Flow network was built according to the ventilation structural characteristics of a 330 MW large water-hydrogen-hydrogen cooled turbogenerator. The variation of the fan inlet velocities, and the flow rates and pressures (boundary conditions) of each end region outlet were obtained, respectively, with different air gap spacer heights and different shelter board widths between the long press fingers by flow network method, and the relative law was analyzed. In order to study the influence of the changed end ventilation structures on the temperature distribution of the end parts, 3-D transient electromagnetic field in the turbogenerator end was calculated, and the eddy current losses (heat sources) of the end parts were gained by the finite-element method. Meanwhile, the fluid and thermal mathematics and physical models of the end region were given. Using the finite-volume method, the influence of the changed end ventilation structures on the surface heat transfer coefficient and the temperature of end parts was researched. It shows that the proper changes in the air gap spacer height and shelter board width decrease the copper shield temperature and result in a reasonable temperature distribution in the end parts. It provides the useful reference for the further design of the large turbogenerators.

Calculation of Ventilation Cooling, Three-Dimensional Electromagnetic Fields, and Temperature Fields of the End Region in a Large Water–Hydrogen–Hydrogen-Cooled Turbogenerator

According to the complex structure characteristics of a 330-MW water-hydrogen-hydrogen-cooled turbogenerator, the flow network within a half-axial segment of the generator was established. The total flow rate, pressure, flow rates of various ventilation ducts, and the chambers in the generator were obtained after solving the equations of the flow network. The 3-D transient electromagnetic field in the generator end was calculated, and the eddy-current losses of the end parts were gained. Using the finite volume method, the fluid and thermal mathematic and physical models for the whole end region were given. The flow velocity and the pressure values from the flow-network calculations were applied to the end region as boundary conditions, and the losses measured from electromagnetic field calculations were applied to the end parts as heat sources in the temperature field. Thus, both the distribution of the temperature of the end parts and the distribution of the fluid flow in the whole end region were obtained under rated operating conditions. Comparing the calculated temperature results with the test values, the errors meet the engineering requirement. All of the aforementioned data will provide an effective basis for accurately calculating the temperature of the end parts in a large turbogenerator.

Influence of Copper Shield Structure on 3-D Electromagnetic Field, Fluid and Temperature Fields in End Region of Large Turbogenerator

A new kind of the copper shield structure called the empty solid copper shield structure (ESCSS) in the large turbogenerator is proposed in this paper. Based on the complex structure characteristics of a 330-MW water-hydrogen-hydrogen cooled turbogenerator, the flow network within a half of the generator is established, and the total flow rate, pressure, flow rates (boundary conditions) of the various ventilation ducts and the chambers in the generator are separately obtained after solving the equations of the flow network when the traditional copper shield structure and the ESCSS are adopted. The 3-D transient electromagnetic field of the generator end region is calculated by using the time-stepping FEM, and the electromagnetic loss distributions (heat sources) are determined separately. Then, the fluid and thermal analysis model for the whole end region is established. Through numerical calculating, the whole end region 3-D fluid and temperature distributions are obtained separately. The results show that the new copper shield structure makes the copper shield temperature much lower. Meanwhile, the copper shield material is saved. The obtained conclusions may provide useful reference for the optimal design and research of the large turbogenerator.