scholarly journals Experimental Investigation of the Water Erosion Resistance of Turbine Blade Materials at Different Impact Angle

Author(s):  
Z. Y. Zhang ◽  
Y. H. Xie ◽  
D. Zhang
2018 ◽  
Vol 238 ◽  
pp. 04007
Author(s):  
Zheyuan Zhang ◽  
Yonghui Xie ◽  
Di Zhang

An experimental system to assess the water erosion resistance of the steam turbine blade material was built. It can conduct the test of the blade material water erosion resistance characteristic with different water jet diameter and different impact velocity. The experimental investigation of the water erosion resistance characteristics of the blade materials with different surface treatment processes are carried out. By weighing the specimens of each stage, the curves of mass loss with time are obtained. The 2D metal micrograph, 3D surface topography and cross section pit curves are achieved with a laser 3D microscopy. The results reveal the characteristics of the specimens at all stages during the experiment. A method was proposed that the water erosion resistance characteristic can be evaluated by the volume loss based on the pit cross section size, which solves the problem that it's difficult to compare the masses with different material densities or coating densities. The experimental study in this paper has great value for the turbine blade material selection in the steam stages and surface protection technology.


Author(s):  
Roger W. Moss ◽  
Roger W. Ainsworth ◽  
Tom Garside

Measurements of turbine blade surface heat transfer in a transient rotor facility are compared with predictions and equivalent cascade data. The rotating measurements involved both forwards and reverse rotation (wake free) experiments. The use of thin-film gauges in the Oxford Rotor Facility provides both time-mean heat transfer levels and the unsteady time history. The time-mean level is not significantly affected by turbulence in the wake; this contrasts with the cascade response to freestream turbulence and simulated wake passing. Heat transfer predictions show the extent to which such phenomena are successfully modelled by a time-steady code. The accurate prediction of transition is seen to be crucial if useful predictions are to be obtained.


Author(s):  
GholamHossein Maleki ◽  
Ali Reza Davari ◽  
Mohammad Reza Soltani

An extensive experimental investigation was conducted to study the effects of Dielectric Barrier Discharge (DBD), on the flow field of an airfoil at low Reynolds number. The DBD was mounted near the leading edge of a section of a wind turbine blade. It is believed that DBD can postpone the separation point on the airfoil by injecting momentum to the flow. The effects of steady actuations on the velocity profiles in the wake region have been investigated. The tests were performed at α = 4 to 36 degrees i.e. from low to deep stall angles of attack regions. Both surface pressure distribution and wake profile show remarkable improvement at high angles of attack, beyond the static stall angle of the airfoil when the plasma actuation was implemented. The drag calculated from the wake momentum deficit has further shown the favorable role of the plasma actuators to control the flow over the airfoil at incidences beyond the static stall angle of attack of this airfoil. The results demonstrated that DBD has been able to postpone the stall onset significantly. It has been observed that the best performance for the plasma actuation for this airfoil is in the deep stall angles of attack range. However, below and near the static stall angles of attack, plasma augmentation was pointed out to have a negligible improvement in the aerodynamic behavior.


Author(s):  
Jian Pu ◽  
Zhaoqing Ke ◽  
Jianhua Wang ◽  
Lei Wang ◽  
Hongde You

This paper presents an experimental investigation on the characteristics of the fluid flow within an entire coolant channel of a low pressure (LP) turbine blade. The serpentine channel, which keeps realistic blade geometry, consists of three passes connected by a 180° sharp bend and a semi-round bend, 2 tip exits and 25 trailing edge exits. The mean velocity fields within several typical cross sections were captured using a particle image velocimetry (PIV) system. Pressure and flow rate at each exit were determined through the measurements of local static pressure and volume flow rate. To optimize the design of LP turbine blade coolant channels, the effect of tip ejection ratio (ER) from 180° sharp bend on the flow characteristics in the coolant channel were experimentally investigated at a series of inlet Reynolds numbers from 25,000 to 50,000. A complex flow pattern, which is different from the previous investigations conducted by a simplified square or rectangular two-pass U-channel, is exhibited from the PIV results. This experimental investigation indicated that: a) in the main flow direction, the regions of separation bubble and flow impingement increase in size with a decrease of the ER; b) the shape, intensity and position of the secondary vortices are changed by the ER; c) the mass flow ratio of each exit to inlet is not sensitive to the inlet Reynolds number; d) the increase of the ER reduces the mass flow ratio through each trailing edge exit to the extent of about 23–28% of the ER = 0 reference under the condition that the tip exit located at 180° bend is full open; e) the pressure drop through the entire coolant channel decreases with an increase in the ER and inlet Reynolds number, and a reduction about 35–40% of the non-dimensional pressure drop is observed at different inlet Reynolds numbers, under the condition that the tip exit located at 180° bend is full open.


Author(s):  
Fang Li ◽  
Shunsen Wang ◽  
Juan Di ◽  
Zhenping Feng

Abstract In order to study the effect of initial surface roughness on water droplet erosion resistance of last stage blade substrate of steam turbine, eight 17-4PH samples were grounded and velvet polished by different mesh metallographic sandpaper to establish sample with different initial surface roughness. The water droplet erosion experiments were carried out in the highspeed jet water erosion experiment system, and the mass and micro-morphology of each sample were measured by using precision electronic balance and ultra-depth of field microscope respectively at each experimental stage, and the measurement of water erosion trace width and maximum water erosion depth were also completed at the same time. On the basis of experiments, LS-DYNA was used for numerical simulation to verify the reliability of experimental results again. Results show that the smoother the initial surface of sample, then the smaller the mass loss, the stronger its water erosion resistance. On the contrary, the rougher the initial surface of sample, the more severe the surface irregularity, the more times the water droplets concentrated at the lowest point of pit when water droplets flow laterally after impact is completed, thus accelerating the formation of initial crack and lateral expansion, the poorer the water erosion resistance of sample. At same water erosion time, the smoother the sample surface, the later the complete erosion trace appear, the narrower the water erosion trace width. However, the maximum water erosion depth of sample is not affected by the initial surface roughness. The numerical simulation results are in good agreement with the experimental results.


2021 ◽  
Vol 871 ◽  
pp. 112-124
Author(s):  
Zheng Zheng Yang ◽  
Jian Zhang ◽  
Xin Hai Yu

In this study, one novel WC/Ni flexible cloth coatings were prepared to enhance the abrasion and erosion resistances and meanwhile to accommodate the complicated component surfaces. Neither precipitation of WC particle nor pores or cracks were detected in the coating. The scarification extent of WC particle decreased with the increase in the WC content. With the abrasion mechanism of three body abrasive wear, the WC/Ni coating with 59.8 wt.% WC (WC/Ni-59.8 wt.%) showed the best abrasion resistance with the wear rate of 0.3% of 304 stainless steel. At 30° of impact angle, the WC/Ni-59.8 wt. % exhibited a superior erosion resistance to that of WC coating developed by high velocity oxygen fuel (HVOF). The application potential of WC/Ni flexible cloth coating for the commercial components was testified by developing the coating on a ball valve disc.


2020 ◽  
Vol 117 ◽  
pp. 104809
Author(s):  
Mahmood Sameezadeh ◽  
Sasan Hasanlou ◽  
Hossein Zafari ◽  
Majid Vaseghi

2021 ◽  
Vol 182 ◽  
pp. 116156
Author(s):  
Mingeon Kim ◽  
Dong Hwan Shin ◽  
Jin Sub Kim ◽  
Bong Jae Lee ◽  
Jungho Lee

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