Concentration Distribution Research of a Special DC Pulverized Coal Burner and Resistance Analysis

2012 ◽  
Author(s):  
Mo Yang ◽  
Chunsun Guo ◽  
Yuwen Zhang ◽  
Zhangyang Kang
Keyword(s):  
Gas Phase ◽  
Solid Phase ◽  
Pulverized Coal ◽  
Discrete Phase Model ◽  
Bias Effect ◽  
Two Phase ◽  
Discrete Phase ◽  
High Concentrations ◽  
Moderate Resistance ◽  
Pulverized Coal Burner

In this paper, a direct current (DC) anti-bias burner has been numerically simulated. This kind burner is combination of bias block and elbow bend and its bias block is located behind the bend. Effects of the bias block’s angle and location on coal distribution in the burner export are investigated. Euler-Lagrange approach is employed to study the gas-solid two-phase flow. The gas-phase is simulated using the RNG k-ε model and solid-phase is modeled using the discrete phase model (DPM). The results show that, installing a bias block behind the elbow can achieve a uniform distribution in outlet and the high concentrations region non-adherent. Relative to the location, the bias block angle changes is the main reason of generating resistance. When α = 25° L = 150mm, the distribution of pulverized coal of the burner outlet is the most uniform and the resistance is not large, which could satisfy the good anti-bias effect and moderate resistance loss at the same time.

Concentration Distribution Research of a Special DC Pulverized Coal Burner

2011 ◽  
Author(s):  
Mo Yang ◽  
Chunsun Guo ◽  
Yuwen Zhang ◽  
Zhangyang Kang
Keyword(s):  
Concentration Distribution ◽  
Solid Phase ◽  
Pulverized Coal ◽  
Phase Model ◽  
Discrete Phase Model ◽  
Lagrange Method ◽  
Two Phase ◽  
Discrete Phase ◽  
Special Distribution ◽  
Pulverized Coal Burner

There is a burner which bias block is located in different place compared with other pulverized coal burners. This special DC pulverized coal burner is used to achieve uniform distribution of the export concentration. By numerical method, this article has studied the concentration of this special distribution burner and analyzed internal characteristics. In order to research the effect of bias block in concentration distribution, this special distribution burner has been compared with the structure having no bias block. Euler-Lagrange method and discrete phase model (DPM) are employed to study the gas-solid two phase flow. Solid-phase is simulated in discrete phase model (DPM) and gas-phase in separation vortex (DES).

scholarly journals Effect of sand particles on flow structure of free jet from a nozzle

2019 ◽  
Vol 13 (3) ◽  
pp. 5542-5561
Author(s):  
M. J. Al-Dulaimi ◽  
F. A. Hamad ◽  
A. A. Abdul Rasool ◽  
K. A. Ameen
Keyword(s):  
Numerical Simulation ◽  
Mass Flow ◽  
Phase Measurement ◽  
Solid Phase ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Natural Sand ◽  
Free Jet ◽  
Discrete Phase ◽  
Sand Particles

The Characteristics of single and two- phase flow from a circular turbulent free jet from a nozzle of 10 mm diameter were investigated experimentally and numerically. The measurements were conducted for ReJ = 10007 - 31561. The velocity was measured at location from the nozzle y/D (0-8) in axial and radial directions. The two phase measurement were done by using natural construction sand as a solid phase of sizes (220,350,550) µm and loading ratios (mass flow ratio of sand to mass flow rate of air) in the range (0.18-1.38). Two phase air velocity of jet showed that the introducing of natural sand particles gives lower jet velocity attributed to momentum transfer to particles. The smaller particle size leads to lower values of velocity. The velocity found to be decreased with loading ratio increase. The numerical simulation was performed for single and two phase jet flow. RNG K-ε turbulence model was used to simulate the flow of fluid and the discrete phase model to simulate the particles flow. The results form numerical simulation showed a good agreement with experimental results.  

Numerical Simulation of Two-Phase Flow inside and outside a Swirl Nozzle for Dispersing Superfine Powder

2012 ◽  
Vol 505 ◽  
pp. 170-174
Author(s):  
Wei Dong Shi ◽  
Liang Zhang ◽  
Hai Yan He ◽  
Jiang Hai Liu ◽  
Liang Chen
Keyword(s):  
Total Pressure ◽  
Concentration Distribution ◽  
Gas Flow ◽  
Reynolds Stress Model ◽  
Phase Flow ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Discrete Phase ◽  
Particle Group ◽  
Nozzle Structure

In this paper, a swirl nozzle is established to disperse superfine powder aerodynamically. And Reynolds stress model (RSM) is adopted to simulate the strongly swirling, compressible and transonic gas flow in the nozzle and its rear. Combined with discrete phase model (DPM), the concentration distribution of particle group in size of 2.5μm is studied. The simulated results show that, the distribution of swirl strength is determined basically by the nozzle structure, while the total pressure has little effect on it; compared with an irrotational nozzle, the swirl nozzle could achieve a better dispersing effect for superfine powder.

scholarly journals Prediction of Horizontal Pneumatic Conveying of Large Coal Particles Using Discrete Phase Model

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Daolong Yang ◽  
Ge Li ◽  
Yanxiang Wang ◽  
Qingkai Wang ◽  
Jianping Li ◽  
...  
Keyword(s):  
Simulation Method ◽  
Phase Model ◽  
Pneumatic Conveying ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Coal Particles ◽  
Large Particles ◽  
Discrete Phase ◽  
Field Velocity ◽  
Conveying System

The pneumatic conveying focusing on gas-solid two-phase flow plays an important role in a conveying system. Previous work has been conducted in the fields of small particles, where the size was less than 5 mm; however, there are few studies regarding large sizes (>5 mm). In order to predict the horizontal pneumatic conveying of large coal particles, the coupling methods based on the Euler–Lagrange approach and discrete phase model (DPM) have been used for the simulated research. Compared with the experimental results under the same working condition, the particle trajectory obtained by simulation is similar to the particle distribution at the same position in the experiment, and it turns out that the simulation method is feasible for the horizontal pneumatic conveying of large particles. Multifactor simulations are also carried out to analyse the effects of particle size, flow field velocity, solid-gas rate, and pipe diameter on the wall abrasion during horizontal pneumatic conveying, which provides simulation reference and design guide for pneumatic conveying of large particles.

Study of the Effects of Shearer’ Kinematic Parameters on on-Way Distribution of Dust on Coal Face

2011 ◽  
Vol 127 ◽  
pp. 400-405
Author(s):  
Xiao Huo Li ◽  
Shu Ming Liu ◽  
Zhi Long Huang ◽  
Wei Du
Keyword(s):  
Rotational Speed ◽  
Dust Concentration ◽  
Discrete Phase Model ◽  
Kinematic Parameters ◽  
Coal Face ◽  
Two Phase ◽  
Concentration Maximum ◽  
Discrete Phase ◽  
And Migration ◽  
Kinematical Parameters

In order to research the effects of shearer’ kinematical parameters on on-way distribution of dust on coal face, according to the theory of suspension gas-solid two-phase flow and the theory of cutting dust formation, mathematical model of on-way dust concentration was established, methods of determining parameters were given, dust migration was simulated by using the discrete phase model (DPM) in FLUENT, on-way distribution regularity of dust was found. According to calculation of the quantity of cutting dust at different hauling speed and different rotational speed of drum, dust migration was simulated and migration regularity was showed as follows: dust concentration of every point on a coal face increased as hauling speed decreased or rotational speed increased. In addition, with rotational speed increased, the position of concentration maximum moved a little along downwind.

Numerical Simulations of Combustion and Decomposition Processes in Precalciner with Two Different Heights of Raw Meal Inlets

2012 ◽  
Vol 268-270 ◽  
pp. 477-482
Author(s):  
Shu Xia Mei ◽  
Jun Lin Xie ◽  
Feng He ◽  
Ming Fang Jin
Keyword(s):  
Coordinate System ◽  
Numerical Simulations ◽  
Decomposition Rate ◽  
Transport Model ◽  
Solid Phase ◽  
Equation Model ◽  
Discrete Phase Model ◽  
Decomposition Processes ◽  
Discrete Phase ◽  
Lagrange Coordinate

To reduce energy consumption, numerical simulations of combustion and decomposition processes in a precalciner were carried out with two different heights of raw meal inlets. In Euler coordinate system the gas phase is expressed with k-ε two-equation model, in Lagrange coordinate system the solid phase is expressed with discrete phase model (DPM), the chemical reaction is expressed with species transport model, and the radiation is expressed with P1 radiation model. The results show that when the raw meal inlets are near the jetting coal pipes, there is much better dispersing condition of CaCO3 but a much poorer coal combustion condition, resulting in a much higher CaCO3 decomposition rate but a lower coal burn-off rate than that when the raw meal inlets are far away from the jetting coal pipes. It is advised to install both the two heights of raw meal inlets in order to obtain not only high CaCO3 decomposition rate but also high coal burn-off rate.

Effect of particle mass concentration on erosion characteristics of self-priming pump

2021 ◽  
pp. 095440622110007
Author(s):  
Wenqi Zhang ◽  
Shuai Yang ◽  
Dazhuan Wu ◽  
Jiegang Mou
Keyword(s):  
Structural Damage ◽  
Leading Edge ◽  
Discrete Phase Model ◽  
Suction Surface ◽  
Two Phase ◽  
Lower Velocity ◽  
Damage And Failure ◽  
Discrete Phase ◽  
Flow Medium ◽  
Solid Liquid

The self-priming pump is widely used in conveying the solid-liquid two-phase flow medium. The particles in the medium erode the components, leading to structural damage and failure. The computational fluid dynamics (CFD) model of the 65ZW30-20 self-priming pump is built to study erosion characteristics and mechanisms. FLUENT, along with the Discrete Phase Model and Oka erosion model, is applied for the numerical simulation. The particle distribution, impact times and velocity, and trajectories are taken into consideration to investigate the erosion characteristics in each component. The results show that with the increase of the particle concentration, the head and efficiency decreases gradually. The volute wall and blade leading edge are the most vulnerable regions to erosion, because of a large number of impact times and high impact velocity. Also, the particles impact the front gap wall for fewer times and the hub with lower velocity, which leads to a slighter erosion. Besides, the particle trajectories indicate that some particles impact the blade suction surface and the paraxial area of the shroud, rendering considerable erosion.

Simulation of an Aero-Engine Bearing Compartment Using Two-Way Transition Between Lagrangian Droplets and a Three-Dimensional Eulerian Liquid Film

2019 ◽  
Author(s):  
Jean-Sebastien Dick ◽  
Vivek Kumar ◽  
Pravin Nakod ◽  
Federico Montanari
Keyword(s):  
Liquid Film ◽  
Fluid Model ◽  
Three Dimensional ◽  
Mesh Size ◽  
Liquid Structure ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Aero Engine ◽  
Discrete Phase ◽  
Modeling Strategy

Abstract This paper presents a new hybrid two-phase flow numerical model. It uses the Discrete Phase Model (DPM) and the Volume of Fluid model (VoF) to study the interaction between air, oil droplets and films in a bearing compartment. It allows transition from a trackable Lagrangian particle, such as a droplet, into a continuous liquid structure in a Eulerian frame of reference. The transition can also be performed in the opposite direction, where a continuous liquid structure can be converted back into a trackable particle if specific requirements are met. The method is designated as DPM-VoF-DPM throughout this paper. Test cases capturing the impingement of a droplet in a liquid film are performed to assess its effectiveness. The simulation of a simplified bearing compartment is compared with measurements and results obtained using a standard VoF modeling approach. Mechanisms which are usually modeled such as droplet splashing, film separation, and droplet stripping, can now be physically captured with reduced computing resources by allowing transition from continuous liquid structures to discrete parcels. The employed modeling strategy allows for high resolution of the oil film at the walls and tracking of the droplets while minimizing mesh size and computing needs. Current results suggest that the proposed DPM-VoF-DPM method can be an efficient and accurate tool for locating air and oil in aero-engine transmission systems.

Co-Combustion of Pulverized Coal and Biomass in Fluidized Bed of Furnace

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Mitianiec Wladyslaw
Keyword(s):  
Open Source ◽  
Gas Phase ◽  
Flow Rate ◽  
Combustion Process ◽  
Theoretical Description ◽  
Pulverized Coal ◽  
Numerical Code ◽  
Two Phase ◽  
Inlet Flow Rate ◽  
Combustion Processes

Combustion processes of two fuels, pulverized coal and biomass, in furnaces take place at steady state. Combustion of condensed fuels involves one-way interfacial flux due to phenomena in the condensed phase (evaporation or pyrolysis) and reciprocal ones (heterogeneous combustion and gasification). Many of the species injected in the gas phase are later involved in gas phase combustion. This paper presents results of combustion process of two-phase charge contained coal and wetted biomass, where the carrier was the air with given flow rate. The furnace has three inlets with assumed inlet flow rate of coal, biomass, and air, and combustion process takes place in the furnace fluidized space. The simulation of such combustion process was carried out by numerical code of open source computational fluid dynamics (CFD) program code_saturne. For both fuels, the moist biomass with following mass contents: C = 53%, H = 5.8%, O = 37.62%, ash = 3.6, and mean diameter of molecules equal to 0.0008 m and pulverized coal with following mass contents: C = 76.65%, H = 5.16%, O = 9.9%, ash = 6.21%, and mean molecule diameter 0.000025 m were used. Devolatilization process with kinetic reactions was taken into account. Distribution of the main combustion product in furnace space is presented with disappearance of the molecules of fuels. This paper presents theoretical description of the two-phase charge, specification of the thermodynamic state of the charge in inlet boundaries and furnace space, and thermal parameters of solid fuel molecules obtained from the open source postprocessor paraview.

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