Particle Mass Flow Rate Research Articles

Particle erosion in 90-Degree elbow pipe of pneumatic conveying System: Simulation and validation

In this paper, a new comprehensive numerical model is proposed to investigate the particle erosion behaviors (PEBs) in 90-degree elbow pipe (90° EP) of pigsty feed pneumatic conveying system (PFPCS) for gas–solid two-phase flow (GSPF). Calculations of the Re-normalisation group (RNG) k-ε equation, pipeline heat transfer (PHT) equation, and particle tracking (PT) equation are coupled and solved in our model via computational fluid dynamics and discrete phase model (CFD-DPM). Notably, temperature effect, which is the thermophoretic force (FT) is considered and verified for enhancing the prediction accuracy of the erosion rate (η) in this model. Subsequently, this model is used to analyze the η influence of various factors, such as the impact angle (θ), the particle mass flow rate (mp), the particle injection velocity (v), the particle shape factor (κp), the particle diameter (Dp), on the performance of 90° EP of PFPCS. Simultaneously, a visual experimental system for temperature and pressure drop gradient of 90° EP is established for verification. The prediction results via our proposed erosion model are remarkably close to the experimental values by calculating, evaluating and comparing eight kinds of previous erosion models. Furthermore, ηmax increases as the surface temperature of (Text) increases, revealing the interaction between thermophoretic forces, gravity, and fluid drag. Moreover, ηmax initially decreases with the increase of Dp, and then increases when Dp is from 50 μm to 1000 μm, and ηmax increases linearly with the increase of mp. In addition, ηmax first increases with the increase of κp, and then decreases, and ηmax is 1.18 mg·m−2·s−1 at Text = 25℃, κp = 0.8. Therefore, this study provides a theoretical basis and high-performance numerical model for developing a real-time data transmission software, which forms a health monitoring system with the components of PFPCS.

Virginia Tech Optical Inlet Sensor for Particle Detection: Rolls Royce M250 Turboshaft Demonstration

Abstract Propulsion systems are exposed to environmental ingestion hazards that can cause significant damage and decrease performance. Particles are ingested in a wide range of flight environments that can cause immediate engine failure or long-term damage. An accurate measurement technique has been developed to quantify particle ingestion and aid engine health monitoring. This sensor utilizes scattering and extinction techniques along with machine learning models to measure particle characteristics based on a robust and versatile library. The capabilities of this sensor have been demonstrated using solid quartz particles on the Rolls-Royce M250-C20B particle ingestion turboshaft test engine. To the authors' knowledge, this work presents the first demonstration and validation of optical solid particle sensing in a turbine engine. CSPEC sand (Mil-E-5007C) was ingested for the validation test at two different feed rates using a sand feeder. The sand concentrations were 45 mg/m3 and 22 mg/m3. The sensor outputs the particle characteristics of aspect ratio (AR), size distribution (σ), Sauter mean diameter (D32), and the particle mass flowrate. The Sauter mean diameter and mass flowrate of ingested sand were calculated using the machine learning model outputs and validated by independent measurements. The sensor produced a 0.1 g/min RMS error compared to the validation measurement.

Improvement of combustion performance with novel vortex generators in the powder-fueled ramjets

Combustion performance of powder-fueled ramjets depends mainly on the combustor configurations. In this study, three combustors with various vortex generators are put forward firstly in powder-fueled ramjets. The comparison between three novel and the basic configurations is conducted and analyzed by transient numerical simulation. It can be proved that three configurations with various vortex generators have positive effects on the gas-particle phases flow field, mass fractions of products and combustion efficiency. The scheme of tapped vortex generator has best gas-particle flow temperature distribution and most mass fraction of products, meaning more transfer and consumption of powdered fuel. The oxygen content in the scheme of tapped vortex generator, being only 60% of that in basic scheme, also proves the conclusion. Moreover, this configuration also has most mass flow rate of Aluminum gas, products and most particles resided in the combustor, which is 2.25 times than the basic combustor.

Performance Optimization of Underwater Crushing Unit Based on AHP

An underwater crushing unit loaded on the underwater cleaning robot was intended to handle marine biofouling that adhered to the surface of the ship and the dam, and a prototype was initially built. A Computational Fluid Dynamics–Discrete Element Model (CFD-DEM) was created to boost the prototype’s crushing performance, and its rationale was validated by contrasting the simulation results with the results of experimental tests. Accordingly, the primary influences on crushing performance and the laws governing their influence were investigated. The Analytical Hierarchy Process (AHP) method was then used to establish a prediction model for the comprehensive evaluation indicator of crushing performance. The AHP was used, in this case, because of its ability to generate the weight of indicators. The prediction model was a quadratic polynomial function with the rotational speed, the normal velocity component at the outlet of the propeller, the mass flow rate of the particles at the inlet of the unit, and the thickness of the bushing as independent variables. The prediction model fitting effect met the requirements after the test. The primary elements influencing the underwater crushing unit’s performance were optimized using the prediction model. The average accumulation speed of particles in the crushing unit was reduced by 59.05%, and the mass flow rate of particles at the outlet was reduced by 11.93%. The maximum wear height of the bushing was reduced by 33.36%. The specific power was up 20.88%, and the overall crushing performance was up 9.87% when compared to before optimization.

Experimental results for a MW-scale fluidized particle-in-tube solar receiver in its first test campaign

To advance the development of particle-driven technologies, this study presents experimental results of a megawatt-scale solar receiver installed atop the Themis Solar Tower (France). The whole experimental loop and the solar flux distribution at the receiver aperture are described with the associated instrumentation. The solar receiver is composed of forty 4-meter long metallic tubes, and the irradiated part size is 3 m high and 2.6 m wide. The facility was operated at partial load with a maximum solar power of approximately 800 kW with a particle mass flow rate ranging from 2148 kg/h to 12456 kg/h. The tube wall temperature distribution is presented along with a particle temperature increase that reached 400 °C. The dynamic behavior of the solar loop is detailed, in particular the starting phase. The thermal efficiency of the solar receiver ranges from 35 to 63%. An assessment of the lessons learned during this experimental campaign is offered.

Flow irreversibility versus wear of elbow-reducer connection with gas-solid two-phase flow: A numerical study via CFD-DEM coupling method

In industry sectors, such as power, petroleum, and natural gas production, many fluids contain solid particles in gas/liquid-solid two-phase flows. Thus, resistance and wall erosion, which mainly occur at pipe resistance components, such as elbows and reducers, should be considered in the design of conveying pipelines. To examine the interaction of two resistance components, the flow irreversibility versus wear of an elbow-reducer connection with a gas–solid two-phase flow were studied via the CFD–DEM coupling method. The studied connection structures include a reducer at the elbow downstream with distances of 0, 1, and 3 pipe diameters, and a reducer at the elbow upstream with distances of 0, 1, and 3 pipe diameters. Results show that turbulence and wall entropy generation are main reasons for the total entropy generation and flow irreversibility, which are mainly distributed in the interior wall of the elbow and the pipe. The reducer located downstream of the elbow has a good inhibition effect on the fluid with a separation phenomenon. The total entropy generation and maximum erosion rate for the elbow-reducer connections are lower than that for the reducer-elbow connections. Moreover, influences of solid particle mass flow rate and particle size on partial entropy generations, including mean, turbulent, and wall entropy generations, and wall erosion were comparatively analyzed. The simulation results can provide a reference for the design of pipelines to reduce energy consumption and pipeline wear.

Square Cyclone Separator: Performance Analysis Optimization and Operating Condition Variations Using CFD-DPM and Taguchi Method

The square cyclone separator is an efficient separation device for high-temperature gas within Circulating Fluidized Bed (CFB) boilers. Additionally, other operating factors such as particle loading and gas velocity are frequently thought to have considerable influence on fluid flow in gas cyclones, making parameter optimization essential. Finding the most suitable operating configuration can be challenging because of a fundamental understanding of the operating principles, which has yet to be taken into consideration in the literature. The gas flow inside a square cyclone was analyzed using Computational Fluid Dynamics (CFD) for investigating parameters including particle mass flow rate, inlet velocity, inlet temperature, and turbulent intensity in this research. The Taguchi method was utilized as a Design of Experiment (DoE) methodology to maximize separation efficiency. The Analysis of Variance (ANOVA) was conducted to evaluate the relative contribution of each parameter to the performance of the gas cyclone, while the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations were solved using the Eulerian-Lagrangian approach to represent particle movement. Also, Discrete Random Walk (DRW) was incorporated to account for velocity fluctuation. According to a Taguchi analysis, particle mass flow rate is the parameter that has the least impact on cyclone performance, whereas inlet velocity has the most contribution. From the different range of factors examined here, it is proved that the optimal levels of factors for inlet velocity, inlet temperature, particle mass flow rate, and turbulent intensity are, respectively, 20 m/s, 300 K, 180 g/min, and 4%.

Influence of vortical flow induced by a wall-mounted short cylinder with a streamlined front side on a horizontal air–solid two-phase flow

To induce large oscillations of air flow and suspend particles easily near the particle supply point in a low air velocity region of horizontal air-solid two-phase flow, a short cylinder model with a streamlined front side (refer to streamlined model) is proposed and is fixed on the bottom or top of the pipe in front of the particle feed. The streamlined front side of the model is designed to reduce the flow resistance, and the rectangular rear section of the model generates wake vortical flow so as to induce large airflow oscillation. The test tube consists of a horizontal pipe having an inner diameter of 80 mm and a length of 5 m. Spherical polyethylene particles with an average diameter of 2.3 mm and density of 978 kg/m3 were used as the test solid particles. Average air velocities and particle mass flow rates ranged from 9 to 16 m/s and 0.11 to 0.51 kg/s, respectively. Compared with the non-model air-solid two-phase flow, the streamlined model has reduced the pressure drop, critical and minimum conveying air velocities, power consumption, and additional pressure drop. This model achieved the highest reduction rate with a minimum air velocity of approximately 6% and an additional pressure loss of approximately 37.5%. According to particle image velocimetry measurement of air-solid two-phase flow, the time-averaged particle velocity and fluctuating particle velocity generated by the streamlined model are larger than those in the non-model flow, so even low air velocities can easily convey particles.

Hydraulic and Anti-clogging Performance Evaluation of a Novel Cylindrical Drip Emitter using CFD Techniques

An inline cylindrical drip emitter of 4 Lh-1 design flow rate is developed incorporating favourable geometric features against the physical clogging. The emitter model, with one-outlet and two-outlet variants, was tested for its hydraulic and anti-physical-clogging performance using Ansys Fluent 2022 software. The simulated flow rate of 3.988 and 3.992 Lh-1 is found to be very close to the design flow rate. The emitter exponent values of 0.4351 and 0.4406 for the one-outlet and two-outlet variants, respectively, are found to be within the stipulated limit of 0.5 by Bureau of India Standards (BIS) guidelines. The discrete particle modelling (DPM) simulation revealed that 100% of the particles entering the inlets of the emitter variants are escaping within an average residence time of 0.3779-1.036 s for the one-outlet variant and 0.2044-1.005 s for the two-outlet variant. The average residence time increased with increase in the particle size from 0.1 µm to 100 µm, however the same is not affected by the mass flow rate of particles. Overall, the novel cylindrical emitter developed is found to be satisfactory in its hydraulic and anti-physical-clogging performance. Index Terms: CFD, DPM, Ansys fluent, Drip Emitter, Anti- clogging, SST, k-ω Turbulence Model.

Study on the Influence of Different Factors on Pneumatic Conveying in Horizontal Pipe

Aiming at the problems of high energy consumption and particle breakage in the pneumatic conveying process of large-scale breeding enterprises, in this paper, based on the theoretical calculated value of particle suspension velocity, a computational fluid model and a discrete element model are established based on computational fluid dynamics (CFD) and discrete element method (DEM). Then, through the numerical simulation of gas-solid two-phase flow, the influence of four factors of conveying wind speed, particle mass flow rate, pipe diameter, and particle size on the velocity distribution of particles in a horizontal pipe, dynamic pressure change in the pipe, pressure drop in the pipe, and solid mass concentration are studied. The results show that the k-ε turbulence model can better simulate the movement of gas-solid two-phase flow, and through the analysis of the simulation, the influence of four different factors on the conveying characteristics is obtained, which provides a scientific basis for the construction of the conveying line.

Textile multifilament biomaterials: surface modification by N2 jet particle projection towards improved topography

Foreign Body Reaction (FBR) is a critical issue when polyester textiles are used as medical implants to perform hernia repair, stenosed artery replacement or aneurysm pathology treatment. Whatever the application, the natural porosity of textile materials tends to induce exaggerated biological tissue in-growth after implantation. This mechanism can prevent the implant from remaining flexible and should be limited. It has been shown in literature that one potential strategy to limit the FBR process is to increase the surface roughness of the implanted material, as fibroblasts proliferate slowlier on irregular surfaces. The purpose of this study was to investigate the potential of modifying the topography of textile surfaces using a particle projection technology. A supercritical N2 jet was used to spray corundum particles on multi-filament PET woven surfaces. The impact of the particles created local filament ruptures on the treated surfaces towards hairiness increase. The influence of the jet projection parameters such as pressure, standoff distance (SoD), particle size and mass flow rate on the textile surface roughness was investigated. Two constructions were considered for comparison purpose (plain weave constructions characterized by 34 and 28 weft yarns/cm). The results show that under certain projection conditions, particles can generate a layer of frayed fibers on the textile surface. It comes out that regular hairiness is obtained on the sample surface with following set up adjustment parameters: pressure of 900 bars, SoD of 400 mm and a particle mass flow rate of 0.6 g/s. The interaction of the treated surfaces with mesenchymal stem cells (MSC) was then assessed in vitro in order to identify how hairiness may modify the adhesion (at 24 h) and the proliferation (at 72 h) of the seeded cells. The results show that the obtained hairiness of treated textile surfaces helps limiting cell proliferation in contrast to non-treated surfaces.

Numerical study of particle deposition characteristics in a new type of reinforced pipe

When the heat exchanger is working, the medium often contains small impurity particles. Some particles will form dirt in the tubeline during operation, thus increasing energy consumption. This paper presents a new type of reinforced heat exchange tube. The Lagrange model and User-defined Function (UDF) in FLUENT software are used to compile the particle deposition judgment conditions, establish the particle ablation model, and study the effects of inlet flow rate, inlet temperature and particle size on the particle deposition characteristics of straight, twisted and new tubes. The liquid results showed that when the inlet flow rate is 0.6 m/s, the inlet cooling water temperature is 27 °C, the outer wall temperature is 78 °C, the wall roughness is 0.05 mm, and the particle size is 1 μm. When the particle mass flow rate is 0.0005 kg/s, the particle deposition rate in the new tube reaches the minimum value of 30.1% at 19.2 h These data showed that the structure of the new tubeline will not only cause the fluid to rotate, but also cause the fluid to expand and contract, thus increasing the turbulence. The new enhanced heat exchange tube has excellent performance in inhibiting particle deposition.

Particle mass flow determination in dust-laden supersonic flows by means of simultaneous application of optical measurement techniques

Particle mass flow rate and particle mass concentration are key parameters for describing two-phase flows, especially for particle-induced heating augmentation analysis. This work addresses the question of how accurate particle mass flow rate can be determined with three non-intrusive measurement approaches, based on shadowgraphy, particle tracking velocimetry (PTV), and scattered light intensity, in supersonic flows. In terms of shadowgraphy and PTV, the particle mass flow rate was determined by measuring individual particle characteristics, namely particle size, velocity, and density, as well as the measurement volume. The presented shadowgraphy procedure is based on the commercial LaVision DaVis software and additional shadowgraphy corrections. Multiple tests were conducted in the experimental test facility GBK of DLR with varying flow conditions, at a Mach number of 2.1, unit Reynolds number (Re∞) ranging from 5e7 1/m to 1.5e8 1/m, total temperature (T0) ranging from 303 to 544 K, and particle materials, namely Al2O3, MgO, and SiO2, in the size range of 1 to 60 µm. Particle size distributions of Al2O3 and MgO particles could be reproduced with shadowgraphy quite well, while the PTV procedure resulted in non-similar distributions. Pycnometer measurements indicated MgO particle density to be significantly lower than reference values. A DaVis parameter variation analysis resulted in a particle mass flow rate uncertainty of shadowgraphy of up to 30%. The particle mass flow rate uncertainty of PTV is approx. 76%, and the respective uncertainty of scaled PTV and scattered light intensity approach is 28%. The particle mass flow rate, measured with shadowgraphy, is 58% higher than those of the semi-axisymmetric scattered light intensity approach, which can be explained by a higher particle concentration at the injection plane.

Experimental and simulation analysis of erosion law of crude gas production channel in underground coal gasification production wellhead

In underground coal gasification, crude gas carrying coal ash and cinder has a serious significant erosion effect on the gas extraction area of a wellhead device. To study the erosion of the wellhead device, based on the gas-solid two-phase flow theory, this study uses the discrete phase model to describe the kinematics and trajectories of discrete solid particles and uses the Reynolds-averaged Navier-Stokes equation to calculate the fluid dynamics of the continuous phase. This study determines the main erosion position and the maximum erosion angle range of the wellhead device through numerical analysis, as well as the influence of the changes in solid particle size, particle mass flow rate, and crude gas flow rate on the erosion rate, and predicts the service lifetime of the small four-way and side valve I. The gas-solid erosion experiment verified the maximum erosion angle of the wellhead device. The experimental results were consistent with the numerical analysis results. This study also proposes an optimization method of surfacing to reduce the erosion of gas-solid two-phase flow on wellhead devices. The results show that the inner walls of the small four-way and side valve I are the most eroded. Factors such as particle size, particle mass flow rate, and crude gas flow rate have a greater impact on the erosion rate of the device, and the particle size has the greatest impact. Surfacing the severely eroded area of the wellhead device can effectively reduce the erosion and wear of the wellhead device caused by the gas-solid two-phase flow. This study provides guidance for the reasonable prediction and effective protection of severe erosion areas of wellhead devices.

CFD-DEM simulation of distribution and agglomeration characteristics of bendable chain-like biomass particles in a fluidized bed reactor

Biomass is gradually perceived as an important carbon neutral and renewable energy source. Generally, the pretreatment dehydration of non-spherical biomass particles is a crucial process in biomass production. The effectiveness of moisture removal, however, is directly affected by the fluidization characteristics of particles in drying facilities. In this article, the distribution and agglomeration characteristics of chain-like biomass particles in a fluidized bed were studied according to the coupled model through the computational fluid dynamics-discrete element method. Based on the special structural feature of filamentous biomass particles, a new three-dimensional model of bendable chain-like particle was established. The effects of gas superficial velocity and mass flow rate of biomass particle on the distribution and agglomeration characteristics of chain-like biomass particles were experimentally and numerically investigated. The results demonstrated that the chain-like biomass particles were more likely to agglomerate near the wall and corners due to wall effects, with a maximum of 0.11 % of the volume fraction. The distribution of particle concentration showed an inverted C-shape at the lower cross section. Also, the velocity of biomass particles presented as an open downward parabolic distribution in the radial direction and reached a maximum at the central region. The maximum cluster area of chain-like biomass particles was 73.43 cm2 under the condition of ug = 5.71 m/s, appearing in the corners and bottom of the fluidized bed. The band-like clusters transformed into irregular triangular clusters gradually with the increase of the gas velocity. As the particle mass flow rate increased, the particle clusters became larger and extended upward along the tube wall. The results will provide valuable information on the mixing processes of non-spherical particles, as well as guidance for the development and optimization of multi-phase drying plants.

ОЦЕНКА ЭФФЕКТИВНОСТИ СЕПАРАТОРА С СООСНО РАСПОЛОЖЕННЫМИ ТРУБАМИ ПРИОБЕСПЫЛИВАНИИ ГАЗОВЫХ ВЫБРОСОВ ПРИ РАЗЛИЧНОМ УГЛЕ РАСКРЫТИЯ ПРЯМОУГОЛЬНЫХ ЩЕЛЕЙ

An important task in dedusting gas emissions at chemical industry enterprises is to achieve high efficiency. A complex of devices is used for this. Large particles are removed from gases in coarse cleaning devices. Fine particles are removed from gases in fine cleaning devices. However, fine filters are quickly clogged, which leads to an increase in hydraulic resistance and, in some cases, to a decrease in efficiency. An urgent task is to increase their service life and increase efficiency. For this purpose, the paper proposes the design of a separator with coaxially arranged pipes, which is proposed to be installed in front of fine filters. The aim of this work is to numerically investigate the effect of the angle of opening of rectangular slits on the efficiency and hydraulic resistance of a separator with coaxially arranged pipes. The article presents the design of the separator. The principle of operation is described. During numerical calculations, the inlet velocity of the gas flow was set at the inlet of the device, which varied from 3 to 10 m/s, and the mass flow rate of particles was 5 g/s. The particle density varied from 1000 to 3000 kg/m3. The particle diameter varied from 1 to 15 microns. The opening angle of the slits varied from 16 to 24 °. During the calculations, the following main conclusions were made: the structure of vortices in the inter-tube space determines the degree of efficiency of a separator with coaxially arranged pipes, with the angle of opening of rectangular slits α = 20 °, the maximum separation efficiency of fine particles up to 10 microns in size from a dusty stream is equal to an average of 40.3%, the separation efficiency of fine particles from a dusty stream is achieved. the flow rate increases with an increase in the input gas velocity and particle density, because they are easier to dislodge from the swirling gas, the pressure loss in the separator with coaxially arranged pipes is no more than 626 Pa.

Experimental characterization of extreme temperature granular flows for solar thermal energy transport and storage

High-temperature, dense granular flows along an inclined plane were considered for solar thermal energy transport and storage with sintered bauxite particles. A series of experiments was performed for particle inlet temperatures of ∼ 200, 400, 600, and 800 °C to understand the mechanisms of granular flows at extreme temperatures. Mass flow rates were measured using a load cell and free-surface velocities were measured and computed using particle image velocimetry. Surface temperatures were measured using infrared cameras. A significant decrease in steady-state particle mass flow rate was observed with increasing temperature due to changing flow properties. A decrease in bulk particle free-surface velocities was observed at higher temperatures. Free-surface velocity measurement error between experiments were within 20% of the average. The particle surface temperatures decreased from inlet to outlet with larger gradients at higher temperatures observed due to increasing convection and radiative heat losses. A decrease in temperature was observed along the side walls due to a decrease in particle velocities. • Refractory granular media enable high temperature solar thermal energy storage. • Granular flow experiments on inclined plane explored at elevated temperatures. • Significant changes in flow behavior observed at elevated temperatures. • Larger heat loss to surroundings observed at side walls due to decrease in velocity.

GPU-Accelerated infrared signature analysis model based on the Reverse Monte Carlo method

High-fidelity scene simulations are now possible thanks to advancements in computer technology. A fast analysis model for target infrared signature was developed by using the Graphics Processor Unit (GPU) device. The Malkmus statistical narrow band model is used to calculate the gas band-averaged transmittance. Mie scattering theory is used to calculate the particle scattering parameters, and based on the assumption that particles scatter light independently, the albedo and phase functions of the participating media are determined. The Reverse Monte Carlo method (RMCM) is used to complete the radiative transfer. Finally, a GPU device is used to accelerate the ray tracing process and achieve fast calculation of radiation. The calculation results show that the fast analysis model with high accuracy, and compared to Central Processing Unit (CPU) serial programs, the computational performance is greatly improved, with an acceleration ratio of more than 60. The thread block size has a significant impact on the occupancy and acceleration ratio, and the highest computational performance is obtained with the thread block size of 128. The scattering will reduce the acceleration ratio of the fast analysis model, and the performance will be reduced as the particle mass flow rate increases.

A comprehensive evaluation of the anti-erosion characteristics of several new structural elbows in the pneumatic conveying system

The anti-erosion design of elbows is a critical issue, which is directly related to the life of the pipeline. To improve the anti-erosion characteristics of elbows, three types of elbow structure with circumferentially distributed bionic transverse grooves, bionic ribs, and a single rib on the inner wall are proposed. The forms of the grooves or ribs in each type of structure described are selected as square or triangular shapes. The anti-erosion performances of the proposed three types of structures under different working conditions are evaluated using a numerical simulation method. The results show that all types of structures have certain anti-erosion properties because they can change the particle trajectory and affect the flow in the near-wall region. The shape of the grooves or ribs has a significant effect on the anti-erosion properties. The structure with triangular grooves or ribs shows better erosion resistance than the structure with square grooves or ribs, due to lower impact frequency between the particles and the wall. Among several structures, the triangle single rib has the best erosion resistance at 20°, and the maximum erosion rate is 47% lower than that of the ordinary elbow. The bionic triangle transverse grooves structure ranks second, followed by the bionic triangle ribs structure, the bionic square transverse grooves, and the bionic square ribs, respectively. With changes in velocities and particle mass flow rates, the order of erosion resistance does not vary. The conclusion provides a new concept for optimizing the design of erosion-resistant elbows. • Three new types of anti-erosion elbow structures are proposed. • Three types of anti-erosion elbow structures were evaluated comprehensively. • The triangular single rib has the best erosion resistance at 20°which increases 47%. • The single rib is resistant to erosion only before 35°.

Numerical Investigation on Particle Erosion Characteristics of the Elbow Pipe in Gas-Steam Ejection Power System

In gas-steam ejection power systems, the Al2O3 particles in combustion products can cause severe erosion on the downstream elbow pipe. To calculate the particle erosion, a modelling approach is developed by combining a discrete phase model with a flow-thermal coupling model and introducing wall temperature parameters into the erosion model. Furthermore, the influence of particle size, total temperature and pressure, and particle mass flow rate was investigated. The results show that high temperature erosion depth can be expressed as the product of the time integral of temperature factor and the erosion rate at room temperature and is 1.63–3.57 times that at room temperature under different particle sizes. With the increase of particle size, the maximum erosion position tends to the inlet of the bend, and its value increases first and then decreases with the peak value 0.418 mm at particle diameter of 100 µm. The decrease in total temperature and total pressure reduces the erosion rate by reducing the particle velocity. The particle mass flow rate affects the gas-particle flow which, may cause the erosion to change greatly, especially when particle diameter is below 40 µm.