Optimization of Curtis stage in 1 MW steam turbine

When operating at 3000 rpm, small turbines do not require a gear box and the generator does not require complex electronic software. This paper analyses the various geometries of the Curtis stage, comprising two rotor and stator blades with and without an outlet, from the efficiency point of view. Presented are 3D steady viscous flows. The results were compared with the performance of an axial turbine

Computational fluid dynamics analysis of several designs of a Curtis wheel

In small steam turbines, sometimes the efficiency is not as important as the cost of manufacturing the turbine. The Curtis wheel is a solution allowing to develop a low output turbine of compact size and with a low number of stages. This paper presents three fully dimensional computational fluid dynamics cases of a Curtis stage with full and partial admission. A 1 MW steam turbine with a Curtis stage have been designed. The fully admitted stage reaches a power of over 3 MW. In order to limit its output power to about 1 MW, the partial admission was applied. Five variants of the Curtis stage partial admission were analyzed. Theoretical relations were used to predict the partial admission losses which were compared with a three-dimensional simulations. An analysis of the flow and forces acting on rotor blades was also performed

Various inlet spiral geometries in 1MW steam turbine

In small turbines, inlets can be designed using an inlet spiral. This paper analyses the efficiency of eight turbine variants, including seven with three stator and rotor blades and inlet spirals of various geometries, and one variant with a spiral, three stages and an outlet. This involves a 3D steady viscous flow using ANSYS CFX. The analysis shows that the spiral has a considerable influence on turbine efficiency

New blade tip-timing system for measuring rotor blade vibration of steam and gas turbines

One of the crucial issues regarding turbine maintenance is registering blade vibrations. These vibrations can cause serious damage to the engine. Turbine blade vibrations were measured during nominal speed as well as during run up and run down. A new, low cost Blade Tip Timing (BTT) is presented in this paper. It composes of two main modules: the FPGA unit and PC unit. The system is based on the TerasIC DE0-CV development board controlled by the Cyclone V 5CEBA4F23C7 chip. Units communicate via an Ethernet interface. The system measures a signal for every revolution as well as up to three signals coming from independent rotor blade sensors. The PC unit records these data in .csv files. The system can be adapted to process the signals of additional sensors. The measurements of the 1st stage compressor blade vibrations in an SO-3 engine prove that the system works correctly, with no data loss during transmission between system units, and compares well with other measurement systems as well as numerical results