Liquid droplet impingement erosion pdf

Numerical study on liquid droplet impingement erosion in bwrs article pdf available in transactions of the american nuclear society 101. Simulation of droplet impingement on a solid surface by. Corrosionpedia what is a liquid impingement erosion test. Most of what is known about liquid drop impacts with a solid surface has been derived from highspeed photographs,l 2 fig. Experiments on liquid droplet impingement erosion on a rough. In both, the damage is associated with repeated, smallscale, highintensity pressure pulses acting on the solid surface. Integrated super computational prediction of liquid droplet. Request pdf the effect of liquid film on liquid droplet impingement erosion in the present paper, the pipewall thinning due to liquid droplet impingement erosion is studied experimentally by. Liquid droplet erosion for the assessment of the erosion resistance of a material it is necessary to verify the dependence on the peripheral velocity and droplet size. K wood 1university of southampton, highfield, southampton, so17 1bj, united kingdom ac. Mechanical components such as steam turbine blades may experience heavy damage when subjected to repeated impingement of liquid droplets.

Erosion model the nondimensional erosion rate vm due to the liquid droplet impingement erosion for pure aluminum can be formulated by the following equation considering the in. The physics of droplet impingement are related not. Numerical analysis of damping effect of liquid film on. Peak erosion rate was found at small relative groove roughness. Water droplet erosion wde is a result of repetitive highspeed water droplet impacts on solid surfaces which generate impulsive pressure 1. However, there are differences, since the continuous jet produces stagnation pressure, whereas the discrete impacts in water droplet erosion produce much higher shockwave pressures. Jan 08, 2019 impingement corrosion and cavitation are mechanically occurring degradations.

Since ldie locally occurs, it is difficult to detect the damaged area. This is most beneficial to service environments wherein solid areas are subjected to repetitive impacts by jets or liquid drops. Pdf on nov 3, 2009, rui li and others published numerical study on liquid droplet impingement erosion in bwrs find, read and cite all the research you need on researchgate. Formation of the erosive wear of austenitic steel under multicycle droplet impingement impact has been studied. Liquid droplet surface impact interactions droplet and target shockwave behavior.

The influence of material hardness on liquid droplet. It has been shown that, with an existing relief on the steel surface, the bubble cavitation becomes the predominant wear factor under droplet impingement erosion. One of the parameters influencing the liquid impingement erosion remarkably is droplet size. Formation of the erosive wear of austenitic steel under multicycle dropletimpingement impact has been studied.

Droplet diameter measurements for the prediction of liquid. Liquid droplet impingement erosion on groove roughness. Pdf numerical study on liquid droplet impingement erosion. Droplet impingement on solid surfaces is of great importance to inkjet printing 1, spraycooling 2, 3, combustion 4, and coating processes 5. The ldi phenomenon is highly damped out by the influence of the liquid film. Development of a ldie prediction theory in the condition. An evaluation system for liquid droplet impingement erosion ldi has been developed to predict the ldi location and the wall thinning rate. Simulation of droplet impingement on a solid surface by the level set method junling hu1, ruoxu jia1, kaitak wan2, xingguo xiong3 1department of mechanical engineering, university of bridgeport, bridgeport, ct 06604 usa 2department of mechanical engineering, northeastern university, boston, ma 02115 usa 3department of electrical and computer engineering. Development of evaluation system of liquid droplet impingement. Evaluation methods for corrosion damage of components in. Similarly, cavitation, as a special case of impingement corrosion, is caused by the collapse of gas bubbles in a liquid near a solid surface.

Obviously the most important technical application in this area is the spray cooling of hot surfaces and the impingement of. It provides simulated impingement conditions between high speed rotating blades and liquid droplets for erosion studies. In the actual pipe wall which numerous droplets always impinge, it is predicted that both a liquid lm exists on a pipe wall surface and, on the other hand, this surface is also eroded by repeated droplet impingement. Pdf the bent pipe wall thinning phenomenon has been often found at the. Influence of impact speed on water droplet erosion of tial. The results from previous studies and knowledge are organized and the ldi evaluation system that involves the 1. It was designed based on the astm international g73 standard. In this paper, threedimensional numerical simulations are conducted for a bent pipe.

Liquid droplet impingement erosion ldi is defined as an erosion phenomenon caused by highspeed droplet attack in a steam flow. Liquid droplet impingement ldi erosion could be regarded to be one of the. This impact wear phenomenon seen in highspeed moving. The conditions for development of the bubble cavitation as well as its mechanisms. Effect of droplet diameter on liquid impingement erosion. Integrated super computational prediction of liquid. Serious damages are possibly caused by high speed droplet impingement on a material surface. Standard test method for liquid impingement erosion using. Erosion in steam and condensate piping is not limited to the abovementioned erosion caused by liquid droplet impingement ldi or high velocity disentrained condensate. A liquid impingement erosion test is a technique for assessing the erosion resistance of certain materials. This experiment allows the evaluation of erosion rate of solid materials due to the impingement of. We found that the volume loss per droplet increases with the 4. Pdf study on pipe wastage mechanism by liquid droplet. Determination of erosion ratios and the dependence on input parameters an energetic method that takes into account the plastic deformations and the plastic work performed upon the solid can be used to calculate the erosion ratios.

The water droplet erosion test was performed using a rotating disk erosion rig with controlled conditions. Head diameter of liquid jet 3 mm water droplet erosion has some similarities to continuous jet impingement jetcutting. The precise failure mechanisms in the solid have been shown to differ. Using fullfield measurements to improve understanding of water droplet erosion of aeroengine fan blades c. In august 2008, the header pipe in the high pressure feedwater heater vent system leaked at a korean nuclear power plant. Liquid droplet impingement ldi erosion could be regarded to be one of the major causes of unexpected troubles occasionally occurred in the inner bent pipe surface. Comparison of cavitation erosion rate with liquid impingement. Observations of droplet impingement on a ceramic porous. Ldie is the phenomenon that the material is damaged by the impact pressure when liquid droplets impinge on the material surface. The liquid droplet impingement erosion is experimentally studied using the highspeed conical spray under the condition that the circular specimen is smaller than the spray diameter. The impact of a 9 mm steel ball, accelerated by a gasgun, is used to produce the liquid slug. This article focuses on the core nature of erosion by liquid impingement, due to the greater appreciation of the distinctions between the different forms of erosion.

Erosion mechanism was examined on single groove roughness. Liquid droplet impingement erosion was studied on rough surface. Development of evaluation system for liquid droplet. Liquid droplet impingement ldi erosion is closely related to the pipe wall thinning by aged deterioration in actual work of the nuclear power plant. Understanding wallthinning erosion of pipelines in nuclear or steam power plants is critically important for predicting and preventing human and material accidents. Liquid droplet impingement erosion was numerically and experimentally studied on groove rough surface. Attenuation of wallthinning rate in deep erosion by liquid droplet impingement droplet generation during liquid jet impingement onto a horizontal plate effective parameters for erosion caused by water droplet impingement and applications to surface treatment technology. Erosion in steam and condensate piping tlv a steam.

In particular, wear of pipe material by liquid droplet impingement ldi erosion in piping system of nuclear power plant is becoming great problem in recent years because of high aging operation 1. Analytical consideration of liquid droplet impingement on. The factors affecting liquid droplet impingement erosion include flow velocity, droplet size, impact angle and so on. After cutting the pipe during refueling outage, it was identified that the leak was. A cavitating liquid jet apparatus based on astm g495 was used for liquid droplet impingement erosion tests. Erosion rate increased with increasing sandpaper roughness. Nasa techaical manordum 83352 a comprehensive analysis of cavitation and liquid impingement erosion data uasala83352 a ccflprebiieife pispli5is cf rezzbc30 cavflaiicr abd liquic iceiegepebl eicsici lata basa 18 p rc boze ac 1 cscl 1lf uncl ae 6326 c7ttl p. In order to evaluate the erosion damage quantitatively, a highspeed erosion test rig utilizing water droplets was used to study the erosion resistance of 12cr steel, cobalt base alloy and titanium alloy. Experiments on liquid droplet impingement erosion on a rough surface the influence of material hardness on liquid droplet impingement erosion attenuation of wallthinning rate in deep erosion by liquid droplet impingement.

Numerical analysis of liquid droplet impingement on rough. In addition, epri 112657, revision ba, revised riskinformed inservice inspection evaluation procedure, includes erosion cavitation in the same flow sensitive. The maximum pressure at the groove bottom suffers from the influence of the groove roughness. In this study, the effect of droplet size on liquid impingement erosion was studied for pure aluminum and lowcarbon steel s15c. In this study, the effect of droplet size on liquid impingement erosion was studied for pure aluminum and lowcarbon. Ti64 substrate isotropic material response to the impact pressure generated by the droplet impingement resolving the stress components in the solid substrate in elastic mode compare the peak stress component with critical material threshold 4. A welldesigned liquid impingement test is to be preferred for elastomers, coatings, and brittle materials, for which size effects may be quite important. Pdf computational fluid dynamics study of liquid droplet. Evaluation of erosion by liquid droplet impingement for. One of the main causes of pipe wall thinning phenomenon of power generation facilities is the liquid droplet impingement erosion ldie.

Critical consideration on wall thinning rate by liquid droplet. Jul 09, 2010 an evaluation system for liquid droplet impingement erosion ldi has been developed to predict the ldi location and the wall thinning rate. Pipe wall thinning due to ldi is sometimes observed in a steam. In this study, the effect of droplet size on liquid impingement erosion was studied for pure aluminum. Numerical study on liquid droplet impingement erosion in bwrs. Liquid droplet impingement erosion ldi is defined as an erosion phenomenon caused by highspeed droplet attack in a wet steam flow. Effect of impact angle on liquid droplet impingement erosion. Numerical case study on the ldie degradation occurred in. Study of fluidstructure interaction in liquid droplet impingement phenomena 151 4. Numerical case study on the ldie degradation occurred in the. Sep 22, 2015 water droplet erosion wde is a result of repetitive highspeed water droplet impacts on solid surfaces which generate impulsive pressure 1. Experiments on liquid droplet impingement erosion by high. There are two phenomena which are the major contributors to impingement damage.

Regularities of steel wear under the impact of discrete. An experimental study on the droplet erosion durability of. Some researchers found a strong increase in erosion with droplet size and the others found a weak dependence. In the present paper, liquid droplet impingement erosion is studied by using a highspeed spray. The erosion model expresses the relationship between the erosion rate and the droplet parameters, which is normally known as the droplet velocity. Liquid droplet impingement erosion occurs at the elbows in steam pipes where droplets impinge at high speed. For current superhydrophobic coating droplet erosion experiment, the impact velocity is extremely low no more than 20ms compared with previous metal erosion studies. Liquid droplet erosion is one of major concerns in the design of modern large fossil steam turbines because it causes serious operational problems such as performance degradation and reduction of service life. The release of the droplet was detected by placing an optical interrupter approximately 5 mm. It is well known that the ldie progress is classified into three stages. The effect of droplet size has been studied since 1927. Condensate recovery piping in particular can be susceptible to erosion from improperly handled flash steam that occurs in the discharge stream. Numerical analysis of droplet impingement using the moving.

Regarding the effect of the impact angle on liquid droplet impingement erosion, fyall et al. The ordering of the materials and their shields as to the erosion resistance may vary depending on the impact velocity and droplet diameter variation. Water droplet erosion of stainless steel steam turbine blades. However, most of the published research on this wear. A calculation methodology proposed for liquid droplet. Demonstration of a sample rotating apparatus that would be used as part of the standard test method for liquid impingement erosion astm g73. Study on pipe wastage mechanism by liquid droplet impingement erosion ii measurement of erosion rate. May 24, 2017 droplet impingement on solid surfaces is of great importance to inkjet printing 1, spraycooling 2, 3, combustion 4, and coating processes 5. Liquid impingement erosion1 friction, lubrication, and. Investigations of droplet impingement on cold surfaces. It has been shown that, with an existing relief on the steel surface, the bubble cavitation becomes the predominant wear factor under dropletimpingement erosion. The erosion rate in the terminal stage of liquid droplet impingement erosion is evaluated from the experimental data. Numerical analysis of droplet impingement using the moving particle semiimplicit method jinbiao xiong, seiichi koshizuka and mikio sakai the university of tokyo, 731 hongo bunkyoku, tokyo 18656, japan received july 2, 2009 and accepted in revised form december 18, 2009. Therefore, it is possible to prevent the occurrence of liquid impingement erosion by operating power plants at low.

Development of evaluation system of liquid droplet. The flow rate was low enough to allow a drop let to form at the needfe tip and detach under its own weight. Reduction in droplet size or particle diameter 39 4. Feb 01, 2017 demonstration of a sample rotating apparatus that would be used as part of the standard test method for liquid impingement erosion astm g73.

Erosion initiates from bottom of groove at large relative roughness. Using fullfield measurements to improve understanding of. Erosion liquid droplet surface impact interactions droplet and target shockwave behavior cavitation erosion model dularet al, 2006 collapse of cavitation cloud. The effect of liquid film on liquid droplet impingement erosion. Any equipment components directly exposed to fluid flow above a certain velocity can suffer impingement erosion. Because ldi usually occurs very locally and is difficult to detect, prediction of ldi location is required for the safety of the plant. The advantages of a liquid impingement test are that droplet or jet sizes and impact velocities can be selected and it can simulate more closely a specific liquid impingement environment. Flashing, liquid droplet impingement, and solid particle erosion in nuclear power plant piping systems. The characteristics of liquid droplet diameter are investigated for the prediction of liquid droplet impingement erosion ldi occurring in a power plant. The analysis of pipe wall thinning phenomenon is a critical issue for the safety and to increase the operation rate of power plants. Since the main factors causing ldi are fluidrelated factors such as droplet velocity and diameter, it is possible to predict the location of ldi attack if the local flow conditions such as. Impingement corrosion and cavitation are mechanically occurring degradations.

This technique has been instrumental in developing understanding of wde and used successfully for over 50 years 4, 7. In order to estimate the erosion rate due to liquid droplet impingement ldi erosion, the erosion model has to be established. An erosion model has been used to analyze the erosion behavior of cocr alloy coated steam turbine blades of composite material. The conditions for development of the bubble cavitation as well as its mechanisms and the regularities of its influence. Wall thinning of pipelines in power plants occurs mainly by flow acceleration corrosion fac, cavitation erosion ce, and liquid droplet impingement erosion lie. Experiments on liquid droplet impingement erosion on a. Request pdf the effect of liquid film on liquid droplet impingement erosion in the present paper, the pipewall thinning due to liquid droplet impingement erosion. Computational fluid dynamics study of liquid droplet.

Oct 03, 20 droplet size range of 50 m elastic solid modeling. Observations of droplet impingement on a ceramic porous surface 2379 fro. Regularities of steel wear under the impact of discrete water. The magnetite is formed by controlling the water chemistry and the temperature of fluid inside the facility. Comprehensive analysis cavitation and liquid impingement. The impact load increases in proportion with the first to second power of the velocity and the erosion rate with the 4th to 5th power.

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