C12-3.43/0.981 Type 12MW Exhaustion and Condensing Stean Turbine

TheQingdaoJienengPowerGroupCompanyinShandongmanufactUreseightseriesofsteamtIJrbinesin140varieties,witheachturbinebelow25MaTheC12-3.43/0.98type12MWexhaustionandcondensingsteamturbinehasthefollowingfeatures:12mW:ipa,435C,0.981Mpa,andh/h,whichcanbeusedi...

Effects of Inlet Swirl on the Flow in a Steam Turbine Exhaust Hood

The flow in the exhaust hood of a condensing steam turbine depends to a considerable extent on the inlet swirl of the flow which changes in tandem with the volumetric flow of steam through the last stage. This study gives a description of experiments which were carried out on the exhaust hood of a 500 MW steam turbine under various conditions, e.g. when there is rated power, when there is an idle run, or when there are various pressures in the condenser. The flow in a model exhaust hood was investigated by means of CFD methods. Computations were performed with the help of the FLUENT 5 code which is based on solving the Navier-Stokes equations while taking the RSM and LES models of turbulence into consideration. The results of the computations are in full conformity with the experiments.

Influences of Inflow Condition on Non-Axisymmetric Flows in Turbine Exhaust Hoods

The complex 3D flow in a steam turbine exhaust hood model with different inlet swirl and inlet total pressure radial distributions has been simulated by employing CFX-5 and analyzed in this paper. It＇s found that the inlet tangential flow angle at hub has a negative effect on the exhaust hood performance, while a negative gradient of inlet total pressure radial distribution has a positive impact on the hood performances. It＇s also numerically con- firmed that a proper distribution of total pressure at hood inlet can successfully eliminate the negative effects caused by the inappropriate inlet swirl distribution and improve the hood aerodynamic performance.

Interaction between Struts and Swirl Flow in Gas Turbine Exhaust Diffusers

The increasing use of gas turbines in combined cycle power plants together with the high amount of kinetic energy in modem gas turbine exhaust flows focuses attention on the design of gas turbine diffusers as the connecting part between the Brayton/Joule and the Rankine parts of the combined cycle. A scale model of a typical gas turbine exhaust diffuser is investigated experimentally. The test rig consists of a radial type, variable swirl generator which provides the exhaust flow corresponding to different gas turbine operating conditions. Static pressure measurements are carried out along the outer diffuser walls and along the hub of the annular part and along the centerline of the conical diffuser. Velocity distributions at several axial positions in the annular and conical diffuser have been measured using a Laser Doppler Velocimeter （LDV）. Pressure recovery coefficients and velocity profiles are depicted as a function of diffuser length for several combinations of swirl strength, tip flow and strut geometries. The diffuser without struts achieved a higher pressure recovery than the diffuser with struts at all swirl angle settings. The diffuser with cylindrical struts achieved a higher pressure recovery than the diffuser with profiled struts at all swirl angle seO.ings. Inlet flows with swirl angles over 18° affected the pressure recovery negatively for all strut configurations.

Influence of rotating wakes on separation in turbine exhaust diffusers

Highly efficient turbine exhaust diffuser cannot be designed without taking into account the unsteady interactions with the last rotating row of the turbine. Former investigations described in the literature show a very high potential compared to that of other parts of turbomachines for improving the diffuser. A scale model of a typical gas turbine exhaust diffuser is investigated experimentally. To investigate the influence of rotating wakes, measurements without a spoke wheel as well as measurements with a variable-speed rotating cylindrical spoke wheel with 2 mm- or 10 mm-spokes simulating turbine rotor wakes were made. Miniaturized 3-hole pneumatic probes as well as a 2D-Laser-Doppler-Velocimeter （LDV） were used to investigate velocity profiles. 122 static pressure tapings were used to measure several axial and circumferential static pressure distributions. Without a spoke-wheel the annular diffuser separates at the shroud for all swirl configurations. For the measurements with the 2 mm spoke wheel, the separating diffuser was unstable while keeping the test rig operating parameters constant. For a non-rotating 10 mm spoke wheel and at rotational speeds less than 1,000 rpm, the annular diffuser separated at the shroud. Increasing the rotational speed of the 10mm spoke wheel, flow did not separate at the shroud and much higher pressure recovery than without spoke wheel has achieved.

Influence of the wakes of rotating spokes on the performance of a turbine exhaust diffuser

The design of turbine exhaust diffusers is still commonly based upon conservative design charts which do not consider the influence of the components installed upstream such as the last turbine stage.Based on investigations with different spoke wheels which approximate the blade wakes of the last turbine stage,the influence of a rotating bladed disc on the flow in a exhaust diffuser is presented.The pressure recovery for an annual diffuser with 15° half cone angle and the 5 mm spoke wheel used in the model test is very high and nearly independent on the rotational speed and the corresponding Strouhal number.For a 20° annual diffuser,the pressure recovery increases with Strouhal number