A Procedure to Predict Solid Particle Erosion in Elbows and Tees

1995 ◽  
Vol 117 (1) ◽  
pp. 45-52 ◽  
Author(s):  
S. A. Shirazi ◽  
J. R. Shadley ◽  
B. S. McLaury ◽  
E. F. Rybicki
Keyword(s):  
Experimental Data ◽  
Impact Velocity ◽  
Erosion Rate ◽  
Operating Conditions ◽  
Fluid Viscosity ◽  
Erosion Rates ◽  
Sand Particles ◽  
Liquid Flows ◽  
The Impact ◽  
Sand Size

A semi-empirical procedure has been developed for predicting erosion rates in pipe geometries, such as elbows and tees. The procedure can be used to estimate safe operating conditions and velocities in oil and gas production where sand is present. In the proposed procedure, a concept is introduced that allows determination of erosion rate for different pipe geometries. In the procedure, based on empirical observations, the erosion rate is related to the impact velocity of sand particles on a pipe fitting wall. A simplified particle tracking model is developed and is used to estimate the impact velocity of sand particles moving in a stagnation region near the pipe wall. A new concept of equivalent stagnation length allows the simplified procedure to be applicable to actual pipe geometries. The “equivalent stagnation regions” of an elbow and a tee geometry of different sizes are obtained from experimental data for small pipe diameters, and a computational model is used to extend the procedure to larger pipe diameters. Currently, the prediction method applies to mild steel and accounts for the effects of sand size, shape, and density; fluid density, viscosity, and flow speed; and pipe size and shape. The proposed method has been verified for gas and liquid flows through several comparisons with experimental data reported in the literature. The results of the model accurately predict the effects of sand size and fluid viscosity observed in the experiments. Furthermore, predicted erosion rates showed good agreement with experimental data for gas, liquid, and gas-liquid flows in several 50.8-mm (2-in.) elbows and tees.

scholarly journals Experimental Evaluation of Erosion of Gunmetal under Asymmetrical Shaped Sand Particle

2015 ◽  
Vol 2015 ◽  
pp. 1-31 ◽  
Author(s):  
Mohammad Asaduzzaman Chowdhury ◽  
Uttam Kumar Debnath ◽  
Dewan Muhammad Nuruzzaman ◽  
Md. Monirul Islam
Keyword(s):  
Impact Velocity ◽  
Wear Behavior ◽  
Maximum Level ◽  
Impact Angle ◽  
Operating Conditions ◽  
Silica Sand ◽  
Sand Particle ◽  
Damage Propagation ◽  
Erosion Efficiency ◽  
The Impact

The erosion characteristics of gunmetal have been evaluated practically at different operating conditions. Asymmetrical silica sand (SiO2) is taken into account as erodent within range of 300–600 μm. The impact velocity within 30–50 m/sec, impact angle 15–900, and stand off distance 15–25 mm are inspected as other relevant operating test conditions. The maximum level of erosion is obtained at impact angle 15° which indicates the ductile manner of the tested gunmetal. The higher the impact velocity, the higher the erosion rate as almost linear fashion is observed. Mass loss of gunmetal reduces with the increase of stand-off distance. A dimensional analysis, erosion efficiency (η), and relationship between friction and erosion indicate the prominent correlation. The test results are designated using Taguchi’s and ANOVA concept.S/Nratio indicates that there are 1.72% deviations that are estimated between predicted and experimental results. To elaborately analyze the results, ANN and GMDH methods are mentioned. After erosion process of tested composite, the damage propagation on surfaces is examined using SEM for the confirmation of possible nature of wear behavior. The elemental composition of eroded test samples at varying percentage of gunmetal is analyzed by EDX analysis.

scholarly journals Экспериментальное и теоретическое исследование высокоскоростного проникания длинных стержневых ударников в песок

2022 ◽  
Vol 92 (3) ◽  
pp. 392
Author(s):  
С.И. Герасимов ◽  
Ю.Ф. Травов ◽  
А.Г. Иоилев ◽  
В.В. Писецкий ◽  
Н.Н. Травова ◽  
...  
Keyword(s):  
Experimental Data ◽  
Critical Velocity ◽  
Impact Velocity ◽  
Material Properties ◽  
Tungsten Heavy Alloy ◽  
30Khgsa Steel ◽  
Long Rod ◽  
The Impact ◽  
Hardening Coefficient ◽  
Penetration Coefficient

Results of computations with the use of improved modified Alekseevskii-Tate theory (IMATT) are compared to experimental data on high-velocity penetration of long rod projectiles into sand in the impact velocity range of V0=0.5-3.5 km/s. Projectiles were made of three different metals: M1 copper, WNZh tungsten heavy alloy and 30KhGSA steel. The value of hardening coefficient k in the linear dependence of the projectile material yield on pressure could be determined using IMATT and experimental data on dependence of differential penetration coefficient K on the penetration velocity. At penetration in regime of the hydrodynamic erosion of projectile, differential penetration coefficient K could be approximated just by dependence on the ratio of the impact velocity of penetration to the value of the critical velocity, above which the projectile deforms plastically during penetration. The values of the critical velocity may differ for specific projectile material properties as well as the density and the humidity of sand.

Impact of Turbine Center Frame Wakes on Downstream Rows in Heavy-Duty Low-Pressure Turbine

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Sara Biagiotti ◽  
Juri Bellucci ◽  
Michele Marconcini ◽  
Andrea Arnone ◽  
Gino Baldi ◽  
...  
Keyword(s):  
Experimental Data ◽  
Low Pressure ◽  
Numerical Approach ◽  
Forced Response ◽  
Operating Conditions ◽  
Response Analysis ◽  
Test Case ◽  
Low Pressure Turbine ◽  
Harmonic Content ◽  
The Impact

Abstract In this work, the effects of turbine center frame (TCF) wakes on the aeromechanical behavior of the downstream low-pressure turbine (LPT) blades are numerically investigated and compared with the experimental data. A small industrial gas turbine has been selected as a test case, composed of a TCF followed by the two low-pressure stages and a turbine rear frame (TRF) before the exhaust plenum. Full annulus unsteady computations of the whole low-pressure module have been performed. Two operating conditions, full (100%) and partial (50%) load, have been investigated with the aim of highlighting the impact of TCF wakes convection and diffusion through the downstream rows. Attention was paid to the harmonic content of rotors’ blades. The results show a slower decay of the wakes through the downstream rows in off-design conditions compared with the design point. The analysis of the rotors’ frequency spectrum reveals that moving from design to off-design conditions, the effect of the TCF does not change significantly. The harmonic contribution of all turbine components has been extracted, highlighting the effect of statoric parts on the last LPT blade. The TCF harmonic content remains the most relevant from an aeromechanic point of view as per experimental evidence, and it is considered for an forced response analysis (FRA) on the last LPT blade itself. Finally, aerodynamic and aeromechanic predictions have been compared with the experimental data to validate the numerical approach. Some general design solutions aimed at mitigating the TCF wakes impact are discussed.

Impact of Turbine Center Frame Wakes on Downstream Rows in Heavy Duty Low Pressure Turbine

2019 ◽  
Author(s):  
Sara Biagiotti ◽  
Juri Bellucci ◽  
Michele Marconcini ◽  
Andrea Arnone ◽  
Gino Baldi ◽  
...  
Keyword(s):  
Experimental Data ◽  
Low Pressure ◽  
Forced Response ◽  
Point Of View ◽  
Operating Conditions ◽  
Response Analysis ◽  
Low Pressure Turbine ◽  
Harmonic Content ◽  
Partial Load ◽  
The Impact

Abstract In this work, the effects of Turbine Center Frame (TCF) wakes on the aeromechanical behavior of the downstream Low Pressure Turbine (LPT) blades are numerically investigated and compared with experimental data. A small industrial gas turbine has been selected as a test case, composed of a TCF followed by the two low pressure stages and a Turbine Rear Frame (TRF) before the exhaust plenum. Full annulus unsteady computations of the whole low-pressure module have been performed. Two operating conditions, full (100%) and partial (50%) load, have been investigated with the aim of highlighting the impact of TCF wakes convection and diffusion through the downstream rows. Attention was paid to the harmonic content of rotors’ blades. From an aerodynamic point of view, the results show a slower decay of the wakes through the downstream rows in off-design conditions as compared to the design point. The wakes generated by the struts at partial load persist throughout the domain outlet, while they are chopped and circumferentially transported by the rotors motion. This is due to the strong incidence variation at which the TCF works, which induces the growth of wide regions of separated flow on the rear part of the struts. Nevertheless, the analysis of the rotors’ frequency spectrum reveals that moving from design to off-design conditions, the effect of the TCF does not change significantly, thanks to the filtering action of the first LPT stage movable Nozzle Guide Vane (NGV). From unsteady calculations the harmonic contribution of all turbine components has been extracted, highlighting the effect of statoric parts on the last LPT blade. Anyhow the TCF harmonic content remains the most relevant from an aeromechanic point of view as per experimental evidence, and it is considered for a Forced Response Analysis (FRA) on the last LPT blade itself. Finally, aerodynamic and aeromechanic predictions have been compared with the experimental data to validate the numerical approach. In the last part of this paper some general design solutions, that can help mitigation of the TCF wakes impact, are discussed.

Adaptive Wiebe Function Parameters for a Port-Fuel Injected Hydrogen-Fueled Engine

2019 ◽  
Author(s):  
Shah Saud Alam ◽  
Christopher Depcik
Keyword(s):  
Experimental Data ◽  
Mass Fraction ◽  
Internal Combustion Engines ◽  
Operating Conditions ◽  
High Mass ◽  
Parameter Determination ◽  
Complete Combustion ◽  
Burn Rate ◽  
The Impact ◽  
Wiebe Function

Abstract Current unmanned aerial vehicle (UAV) propulsion technologies includes hydrogen fuel cells, battery systems, and internal combustion engines (ICE). However, relying on a single propulsion technology might result in a limited operational range. This can be mitigated by utilizing a hybrid configuration involving a battery pack and an ICE or a fuel cell for charging. Due to its significant weight advantage and high mass-specific energy content, hydrogen (H2) is an ideal fuel for both power plant options. However, use of H2 with an ICE requires precise operational control through combustion process simulation with the predictive approximation of the mass fraction burned profile. In this area, the relatively simple single-Wiebe function is widely deployed for a variety of different fuels, as well as combustion regimes. In general, the description of the single-Wiebe function includes the extent of complete combustion (a), magnitude of the maximum burn rate (m), and combustion duration (θd). However, the literature often provides values for these parameters without necessarily relating them to operational characteristics that can influence ICE power. As a result, it is critical to correlate the burn rate of the fuel to ICE operating parameters, such as the engine compression ratio, inlet pressure, mean piston speed, exhaust gas recirculation level, equivalence ratio, and spark timing. Therefore, in an attempt to physically define these parameters, this effort performs a sensitivity analysis using linear regression (least squares method) to assess the impact of engine operating conditions on the Wiebe function in comparison to experimental data for port-fuel injected hydrogen ICEs. The result is a model that can estimate the values of a, m, and θd in combination with a relatively high coefficient of determination (R2) when compared to the experimental mass fraction burned profiles. Finally, others can expand this methodology to any experimental data for engine and fuel-specific Wiebe parameter determination.

Benchmark Study of CFD-Based Prediction Accuracy of the Models Evaluating Particle and Droplet Induced Erosion for Engineering Applications

2020 ◽  
Author(s):  
Shaoxiang Qian ◽  
Shinichiro Kanamaru
Keyword(s):  
Experimental Data ◽  
Prediction Accuracy ◽  
Erosion Rate ◽  
Solid Particles ◽  
Experimental Results ◽  
Liquid Droplets ◽  
Counter Measures ◽  
Erosion Rates ◽  
Benchmark Study ◽  
Erosion Models

Abstract The particles (including solid particles and liquid droplets) existing in multi-phase flow in process plants can cause erosion due to flow turbulence, and thus, result in pipe wall thinning. Hence, it is important to evaluate erosion rate for determining design margin and finding counter-measures. Many models have been proposed for predicting particles induced erosion rate, but there is significant disparity in their prediction accuracy. The present study aims to verify prediction accuracy of some major erosion models utilizing the published experimental data, for applications to engineering. CFD benchmark study was conducted for three different piping geometries to investigate prediction accuracy of solid particle induced erosion rates for five major erosion models. CFD results show that the erosion rates predicted by Grant & Tabakoff model are closest to the experimental results with acceptable prediction accuracy for applications to engineering. Also, CFD benchmark study was also performed to verify the prediction accuracy of droplet induced erosion rates for three erosion models, utilizing the published experimental data. CFD results show that the erosion rates predicted by Haugen model for all the water impingement velocities are closest to the experimental results with acceptable prediction accuracy for applications to engineering.

A Fully Non-Adiabatic Flamelet Generated Manifold Model for High Fidelity Modeling of Turbulent Combustion in Gas Turbine Like Conditions

2020 ◽  
Author(s):  
Rakesh Yadav ◽  
Ishan Verma ◽  
Abhijit Modak ◽  
Shaoping Li
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Turbulent Combustion ◽  
Gas Turbines ◽  
Turbulent Flame ◽  
Operating Conditions ◽  
High Fidelity ◽  
Mixture Density ◽  
Flamelet Generated Manifold ◽  
The Impact

Abstract Flamelet Generated Manifold (FGM) has proven to be an efficient approach to model turbulent combustion across different regimes of combustion. The manifolds are generally created by solving laminar premixed or opposed flow configurations. Gas turbine combustors often involve many strong non-adiabatic events such as multiple temperature boundaries, quenching from cooling and effusion holes, conjugate heat transfer, soot radiation interaction, phase change from spray and the modulation of inlet conditions. The adiabatic assumption of the underlying flamelet generation in the FGM is, therefore, prone to errors in the prediction of flame speed, liner temperatures, and pollutant formation. In this work, a novel approach to generate fully non-adiabatic manifold is proposed and validated. The FGM manifold is created using a series of non-adiabatic flamelets, each flamelet is solved in one-dimensional physical space. The non-adiabatic flamelets are generated with an optimal combination of freely propagating and burner stabilized flames. This hybrid method of the flamelet configuration allows modeling large heat gain and loss without encountering any unrealistic temperature in the flamelet solution. Such fully non-adiabatic flamelets are then convoluted to generate a five-dimensional Non-adiabatic Flamelet Generated Manifold (NFGM) Probability Density Function (PDF.). The average properties such as temperature, mixture density, species concentration, rate of reaction, etc. from PDF are then coupled with the CFD solution. The non-adiabatic flamelets and corresponding NFGM is implemented into ANSYS Fluent software version 2020R1. This approach is validated first for canonical cases, followed by gas turbine like conditions of swirl stabilized methane fueled turbulent flame, developed at DLR Stuttgart as the PRECCINSTA combustor. The experimental data for this combustor is available for multiple operating conditions. A stable operating point (φ = 0.83, P = 30 kW) is chosen. The proposed nonadiabatic NFGM is used with Stress blended eddy simulation (SBES). The current NFGM-SBES results are compared with experimental data as well as the previously published works. The impact of modeling heat release in flamelet is used to analyze the M-shape versus V-shape flame transition and the peaks of the carbon monoxide in mixing shear layers. The findings from the current work, in terms of accuracy, validity and best practices while modeling NFGM-SBES are discussed and summarized. The improved results of NFGM compared to adiabatic FGM are encouraging and provides a potential high-fidelity tool for accurate, yet efficient modeling of turbulent combustion inside gas turbines.

Design and Performance of Slurry Erosion Tester

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
A. Abouel-Kasem ◽  
Y. M. Abd-elrhman ◽  
K. M. Emara ◽  
S. M. Ahmed
Keyword(s):  
Impact Velocity ◽  
Erosion Rate ◽  
Sample Surface ◽  
Erosion Process ◽  
Impingement Angle ◽  
Slurry Erosion ◽  
Erosion Test ◽  
And Performance ◽  
Paint Removal ◽  
The Impact

A slurry whirling arm erosion test ring was constructed and a series of erosion tests and post-erosion analysis were carried out using a paint erosion indication technique. The pattern of the paint removal presented a highly visual and accelerated map for the erosion process and its behavior. Also, the erosion rate of paint removal was investigated under a number of erosion variables. It was observed that the rebounding of the erodent particles from the sample surface play an important role in developing erosion for this tester. The erosion pattern showed that the effect of the rebound particles depends on the impact velocity and impingement angle. It was also observed that the erosion behavior of paint as a function of impingement angle, impact velocity, and erosion time was similar to that reported in literature for engineering materials. The slurry whirling arm erosion tester seems to be promising for simulating the slurry process in real cases.

Formulation and Experimental Validation of a New Erosion Flow Model

2016 ◽  
Author(s):  
Rebecca Owston ◽  
Dalton McKeon
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Empirical Data ◽  
Erosion Rate ◽  
Numerical Models ◽  
Experimental Testing ◽  
Fluid Viscosity ◽  
New Model ◽  
Functional Relationships ◽  
Material Hardness

In the present work, a multivariable study has been conducted to systematically evaluate the effects of impact angle, material hardness, flow rate, sand concentration, particle size, and fluid viscosity on erosion. Experimental testing consisted of a submerged sand slurry jet impacting a flat plate in different orientations. Weight loss data, as well as profilometer surface scans have been collected on coupons to fully define the erosion. Empirical data trends were evaluated to provide insights into functional relationships between erosion rate and the parameters varied in the study. Interestingly, it was determined that scaling of experimental testing with regard to proppant concentration could be accomplished, since erosion rate normalized by the mass of sand impacting the eroded surface proved to be a constant. A total of five existing computational erosion models were evaluated against experimental data for both qualitative and quantitative performance. Results indicate that two models achieve relatively good comparison with experimental data without the need for case-specific tuning of model constants. This suggests that the use of these numerical models for erosion prediction in scenarios where tuning is not possible (due to lack of time/data), may still provide a reasonable estimate for the rate of material loss on equipment. As the culmination of experimental testing and computational benchmarking efforts, a new erosion model was also formulated. This model was based on both the experimental results and behavioral observations from existing submodels. The new model explicitly included contributions to erosion from the following variables: impact velocity, particle size, material hardness, and angle of impact. Improvement in simulated erosion rate agreement with empirical data was observed for all cases over existing submodels. However, those cases with higher particle diameters benefited the most. Using the new model, error compared to experiments was below 50% for all cases except one.

Design Improvement of a Generic Catofin Reactor Air Outlet Header to Reduce the Erosion Using Computational Fluid Dynamic CFD

2021 ◽  
Author(s):  
Ajay Singh Parihar ◽  
Philippe Thomas Lott
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Impact Velocity ◽  
Material Removal ◽  
Erosion Rate ◽  
Oil And Gas ◽  
Solid Particles ◽  
Economic Losses ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact

Abstract Objectives/Scope The objective of the current work is to study the erosion inside the air outlet header of a generic catofin reactors which are used to produce the propylene. During the regular maintenance cycle of these plants, it was found that at several places in the air outlet header region erosion and material removal were reported. Methods, Procedures, Process Erosion wear is the loss of material due to repeated impact of solid particles on a surface and causes major economic losses across diverse industries such as oil and gas, hydraulic transportation, and chemical processes. Erosion severely damages flow passages, valves and pipe fittings, leading to higher replacement costs as well as the loss of valuable production time. For example, some oil and gas fittings can fail after just 30 minutes of operation due to high erosion rates. Engineers need to quickly evaluate the erosion on dozens of design variations to find ways of stretching the part's lifespan in order to reduce costs and maximize process up-time. Erosion is a complex phenomenon that depends on many parameters. Particle parameters can include the following: Particle shape or angularity, particle size and erodent particle hardness. Flow parameters, on the other hand, have a stronger effect on erosion as it determines particle concentration, particle impact angle, and impact velocity. Other parameters affecting erosion are properties of target surface, i.e. surface hardness and multiphase effects Progress in understanding the erosion due to solid particles has been achieved by the use of computational fluid dynamics (CFD). CFD allows the accurate modelling of fluid flow and particle trajectory through pipelines and bends. Once the impact velocity and angle of the particles colliding against the surface are calculated, empirical correlations to quantify the erosion rate can be implemented. Computational Fluid Dynamics (CFD) methodology was used to understand the cause of material removal and further perform design iterations to come up with new design to reduce the erosion drastically. Results, Observations, Conclusions Many design iterations were performed in virtual environment by performing CFD simulations to understand the flow physics as well as impact of various parameters affecting erosion rate inside air outlet header. Each design modification and its impact on erosion rate is compared with base design to check the effectiveness of modification. Finally, with the help of simulation, three better designs were identified, which reduces the erosion drastically. Novel/Additive Information With the help of CFD simulation, one can test various design modifications as well as find a solution in less time and with less cost as compared to cost associated with inspections and repair.

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