Enhancing Thermal Properties of Steam Turbine Blades by Coating with Nanomaterials

Heat resistant coatings are considered for the external surface Low-Pressure Steam Turbines (LPST). 410 stainless steel covered with nano heat resistant coatings consists of a heat resistant connecting layer enhanced by nanoparticles. A commercial paint was modified by using 20%wt of (titanium dioxide (TiO2) - aluminum oxide (Al2O3)) with different concentrations range (25,50,75wt% of TiO2) layers. These nano-coatings paints were airbrushed onto the surface of specimens of steam turbine blades. The test rig and experimental apparatus have been fabricated and collected to accomplish the thermal tests. The samples were subjected to heat resistance and a temperature test approximately similar to the steam turbine's operation condition temperature. The test results are used to choose the nano-coating layer with a concentration that ensures a composition's highest protective properties. The test sample with concentration (paint-(75% Al2O3+25% TiO2)) showed the highest thermal properties compares with the other cases.

Download Full-text

Advanced Water Droplet Erosion Protection for Modern Low Pressure Steam Turbine Steel Blades

Volume 8: Microturbines, Turbochargers and Small Turbomachines; Steam Turbines ◽

10.1115/gt2015-43140 ◽

2015 ◽

Cited By ~ 1

Author(s):

Joerg Schuerhoff ◽

Andrei Ghicov ◽

Karsten Sattler

Keyword(s):

Steam Turbine ◽

Water Droplet ◽

Precipitation Hardening ◽

Turbine Blades ◽

Low Pressure ◽

Steam Turbines ◽

Treatment Facility ◽

Material Loss ◽

Pressure Steam ◽

Steam Turbine Blades

Blades for low pressure steam turbines operate in flows of saturated steam containing water droplets. The water droplets can impact rotating last stage blades mainly on the leading edge suction sides with relative velocities up to several hundred meters per second. Especially on large blades the high impact energy of the droplets can lead to a material loss particularly at the inlet edges close to the blade tips. This effect is well known as “water droplet erosion”. The steam turbine manufacturer use several techniques, like welding or brazing of inlays made of erosion resistant materials to reduce the material loss. Selective, local hardening of the blade leading edges is the preferred solution for new apparatus Siemens steam turbines. A high protection effect combined with high process stability can be ensured with this Siemens hardening technique. Furthermore the heat input and therewith the geometrical change potential is relatively low. The process is flexible and can be adapted to different blade sizes and the required size of the hardened zones. Siemens collected many years of positive operational experience with this protection measure. State of the art turbine blades often have to be developed with precipitation hardening steels and/or a shroud design to fulfill the high operational requirements. A controlled hardening of the inlet edges of such steam turbine blades is difficult if not impossible with conventional methods like flame hardening. The Siemens steam turbine factory in Muelheim, Germany installed a fully automated laser treatment facility equipped with two co-operating robots and two 6 kW high power diode laser to enable the in-house hardening of such blades. Several blade designs from power generation and industrial turbines were successfully laser treated within the first year in operation. This paper describes generally the setup of the laser treatment facility and the application for low pressure steam turbine blades made of precipitation hardening steels and blades with shroud design, including the post laser heat treatments.

Download Full-text

HVOF coating and surface treatment for enhancing droplet erosion resistance of steam turbine blades

Wear ◽

10.1016/s0043-1648(03)00253-9 ◽

2003 ◽

Vol 254 (7-8) ◽

pp. 652-667 ◽

Cited By ~ 64

Author(s):

B.S. Mann ◽

Vivek Arya

Keyword(s):

Surface Treatment ◽

Steam Turbine ◽

Erosion Resistance ◽

Turbine Blades ◽

Hvof Coating ◽

Steam Turbine Blades

Download Full-text

An Improved Test Facility for Studying Deposit Fouling on Steam Turbine Blades

Volume 8: Microturbines, Turbochargers and Small Turbomachines; Steam Turbines ◽

10.1115/gt2016-57575 ◽

2016 ◽

Author(s):

Alan R. May Estebaranz ◽

Richard J. Williams ◽

Simon I. Hogg ◽

Philip W. Dyer

Keyword(s):

Turbine Blades ◽

Steam Pressure ◽

Reactor Vessel ◽

Test Facility ◽

Test Results ◽

Steam Turbines ◽

Steam Power ◽

Scale Test ◽

Steam Turbine Blades ◽

Asme Paper

A laboratory scale test facility has been developed to investigate deposition in steam turbines under conditions that are representative of those in steam power generation cycles. The facility is an advanced two-reactor vessel test arrangement, which is a more flexible and more accurately controllable refinement to the single reactor vessel test arrangement described previously in ASME Paper No. GT2014-25517 [1]. The commissioning of the new test facility is described in this paper, together with the results from a series of tests over a range of steam conditions, which show the effect of steam conditions (particularly steam pressure) on the amount and type of deposits obtained. Comparisons are made between the test results and feedback/experience of copper fouling in real machines.

Download Full-text

Diagnostics and monitoring of the operating condition of steam-turbine blades

Power Technology and Engineering ◽

10.1007/s10749-007-0054-8 ◽

2007 ◽

Vol 41 (5) ◽

pp. 295-301

Author(s):

A. I. Danilin ◽

S. I. Adamov ◽

A. Zh. Chernyavskii ◽

M. I. Serpokrylov

Keyword(s):

Steam Turbine ◽

Turbine Blades ◽

Operating Condition ◽

Steam Turbine Blades

Download Full-text

Water-droplet erosion behavior of high-velocity oxygen-fuel-sprayed coatings for steam turbine blades

Corrosion Reviews ◽

10.1515/corrrev-2021-0049 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Dingjun Li ◽

Peng Jiang ◽

Fan Sun ◽

Xiaohu Yuan ◽

Jianpu Zhang ◽

...

Keyword(s):

Steam Turbine ◽

Water Droplet ◽

Erosion Resistance ◽

Turbine Blades ◽

Impingement Angle ◽

Erosion Behavior ◽

Water Droplet Erosion ◽

Steam Turbine Blades ◽

Oxygen Fuel ◽

Sprayed Coatings

Abstract The water-droplet erosion of low-pressure steam turbine blades under wet steam environments can alter the vibration characteristics of the blade, and lead to its premature failure. Using high-velocity oxygen-fuel (HVOF) sprayed water-droplet erosion resistant coating is beneficial in preventing the erosion failure, while the erosion behavior of such coatings is still not revealed so far. Here, we examined the water-droplet erosion resistance of Cr3C2–25NiCr and WC–10Co–4Cr HVOF sprayed coatings using a pulsed water jet device with different impingement angles. Combined with microscopic characterization, indentation, and adhesion tests, we found that: (1) both of the coatings exhibited a similar three-stage erosion behavior, from the formation of discrete erosion surface cavities and continuous grooves to the broadening and deepening of the groove, (2) the erosion rate accelerates with the increasing impingement angle of the water jet; besides, the impingement angle had a nonlinear effect on the cumulative mass loss, and 30° sample exhibited the smallest mass loss per unit area (3) an improvement in the interfacial adhesion strength, fracture toughness, and hardness of the coating enhanced the water-droplet erosion resistance. These results provide guidance pertaining to the engineering application of water erosion protective coatings on steam turbine blades.

Download Full-text

An Optimization Design Platform for Fir-Tree Root and Groove for Steam Turbine

Volume 8: Microturbines, Turbochargers, and Small Turbomachines; Steam Turbines ◽

10.1115/gt2018-76595 ◽

2018 ◽

Author(s):

Deqi Yu ◽

Xiaojun Zhang ◽

Jiandao Yang ◽

Kai Cheng ◽

Weilin Shu ◽

...

Keyword(s):

Stress Concentration ◽

Steam Turbine ◽

Gas Turbines ◽

High Speed ◽

Optimization Design ◽

Turbine Blades ◽

Local Stress ◽

Optimization Method ◽

Steam Turbines ◽

Geometry Configuration

Fir-tree root and groove profiles are widely used in gas turbine and steam turbine. Normally, the fir-tree root and groove are characterized with straight line, arc or even elliptic fillet and splines, then the parameters of these features were defined as design variables to perform root profile optimization. In ultra-long blades of CCPP and nuclear steam turbines and high-speed blades of industrial steam turbine blades, both the root and groove strength are the key challenges during the design process. Especially, in industrial steam turbines, the geometry of blade is very small but the operation velocity is very high and the blade suffers stress concentration severely. In this paper, two methods for geometry configuration and relevant optimization programs are described. The first one is feature-based using straight lines and arcs to configure the fir-tree root and groove geometry and genetic algorithm for optimization. This method is quite fit for wholly new root and groove design. And the second local optimization method is based on B-splines to configure the geometry where the local stress concentration occurs and the relevant optimization algorithm is used for optimization. Also, several cases are studied as comparison by using the optimization design platform. It can be used not only in steam turbines but also in gas turbines.

Download Full-text