The Experimental And CFD Research Of The Extraction System In Steam Turbines

Thermal power generation plays an important role in China's energy structure, improving the thermal efficiency of steam turbine is a real and significant issue. From the view of thermodynamic process, in the high-power turbine, regenerative cycle and reheat cycle could improve the thermal efficiency of the unit, which need to extract steam from the turbine. But extraction will cause the flow change at the turbine flow path near the extraction export, which will affect the flow efficiency. And the flow loss of extraction system has an important impact on the flow amount of extraction and calculation of the thermodynamic process. So it has a certain academic value and engineering significance to research on the extraction system.This paper uses experimental and numerical methods to study the typical extraction systems of different units, the data of flow loss was acquired, combined with the flow field, the loss model of engineering was established. The following is the main content:The subject investigated was a reduced-scale model of an ultra supercritical steam turbine, build the test bench. The flow flied,pressure distribution and performance of the extraction modelwas measured with a pressure scanning valve, a hot-wireanemometry and a TR-PIV system.2. Based on the experimental study, numerical simulation wascarried out, which was compared with the experimental result tovalidate the reasonableness and accuracy of the numerical modeland parameter. Combine with the flow field, the loss sources isdetermined and the flow loss is given quantitativelyof the extraction system.3. Study on the actual drawings of a ultra-supercritical and asupercritical steam turbine, establish the extraction models andgenerate the mesh, use steam as fluid for numerical calculation.The flow field and performance characteristics of the extractionmodels were acquired, and the flow loss at different parts of themodel is given quantitatively.4.An engineering method is used to calculate the flow loss of theextraction models, which is compared with one from the CFDresult to validate the accuracy of the engineering method .