Modern mechanical drive steam turbines for oil & gas applications typically expand very high pressure steam, from upwards of 2000 psia to sub-atmospheric condenser pressures. The wheel space diameters for the larger cracked gas (CG) drivers tend to be large due to the high mass flows required. The high pressure and large wheel diameters combine to generate high thrust forces. Industry standards require oversizing of thrust bearings to handle uncertainty in thrust predictions. Increasing plant capacity makes improvement in prediction accuracy and mitigation strategies important.

This paper presents preliminary results of thrust measurements in a full-size, axial steam turbine test rig. The test rig was operated with a single inlet stage, at a nominal base diameter of 25”. The wheel space was instrumented for pressure measurements. Bearing thrust forces were measured with load cells in each of the bearing pads. The rig was operated over a wide range of operating conditions, as well as at varying admission fractions. The wheel space leakage was measured by metering the high pressure packing flow.

The design and operability considerations of the test rig are described in detail. The test rig can also be operated in a multi stage configuration. The test rig can operate at inlet pressures in excess of 100 psia and temperatures up to 600 F. A hydraulic dynamometer is used to present a controllable driven load to the turbine, and a torquemeter coupling is used to measure the turbine shaft power. Internal instrumentation provides measurements of thermodynamic conditions at the stage inlet and exit.


Thrust Force Measurements in an Axial Steam Turbine Test Rig

Division / Sponsor:
International Gas Turbine Institute (IGTI)

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2020/volume/84058

Turbo Expo - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.