Numerical calculations for two-phase jet flow of a mixture of pulverized-coal and gas

1985 ◽  
Vol 1 (1) ◽  
pp. 37-48
Author(s):  
Guo Bentie ◽  
Fan Zhengqiao ◽  
Zhang Benzhao ◽  
Ding Jianmin
Keyword(s):  
Jet Flow ◽  
Pulverized Coal ◽  
Numerical Calculations ◽  
Two Phase

A HOMOGENEOUS NON-EQUILIBRIUM TWO-PHASE CRITICAL FLOW MODEL FOR THE ANALYSIS OF SUPERSONIC JET FLOW

1990 ◽  
Author(s):  
S. Dickman ◽  
Ezra Elias ◽  
S. Kaizerman ◽  
E. Wacholder ◽  
S. Olek
Keyword(s):  
Flow Model ◽  
Supersonic Jet ◽  
Jet Flow ◽  
Critical Flow ◽  
Two Phase ◽  
Non Equilibrium

Numerical Study on the Erosion Characteristics of U-Type Bend for Gas Solid Flow

2017 ◽  
Author(s):  
Yu Wang ◽  
Qi He ◽  
Ming Liu ◽  
Weixiong Chen ◽  
Junjie Yan
Keyword(s):  
Particle Size ◽  
Erosion Rate ◽  
Loading Rate ◽  
Pipe Wall ◽  
Numerical Study ◽  
Pulverized Coal ◽  
Mass Loading ◽  
Two Phase ◽  
Inlet Velocity ◽  
Pipe System

In pulverized coal-fired plant, the U-type bend is commonly used in flue gas and pulverized coal pipe system to due to the constraints of outer space. And gas-solid two-phase flow exists in these pipelines. The erosion of the pipe has significant effect on the safety and reliability of pipelines. In present paper, the erosion characteristics of U-type bend were investigated through CFD (Computational Fluid Dynamics) method. The wear distribution on the pipe wall was obtained. And the particle flow characteristics in U-type bend were analyzed. The influence of inlet velocity, mass loading rate and particle size on the erosion rate was studied as well. Result suggested that the maximum erosion rate increases exponentially with the increase of inlet velocity. And maximum erosion rate increases linearly with the increasing mass loading rate. Increasing particle size can aggravate the wear on the pipe wall.

Numerical Solution of the Two-Phase Stefan Problem in the Enthalpy Formulation with Smoothing the Coefficients

2021 ◽  
pp. 4-23
Author(s):  
V.I. Vasilyev ◽  
M.V. Vasilyeva ◽  
S.P. Stepanov ◽  
N.I. Sidnyaev ◽  
O.I. Matveeva ◽  
...  
Keyword(s):  
Numerical Solution ◽  
Stefan Problem ◽  
Large Diameter ◽  
Discontinuous Coefficients ◽  
Numerical Calculations ◽  
Smooth Functions ◽  
Two Phase ◽  
Time Layer ◽  
Dirac Delta ◽  
Selection Of

To simulate heat transfer processes with phase transitions, the classical enthalpy model of Stefan is used, accompanied by phase transformations of the medium with absorption and release of latent heat of a change in the state of aggregation. The paper introduces a solution to the two-phase Stefan problem for a one-dimensional quasilinear second-order parabolic equation with discontinuous coefficients. A method for smearing the Dirac delta function using the smoothing of discontinuous coefficients by smooth functions is proposed. The method is based on the use of the integral of errors and the Gaussian normal distribution with an automated selection of the value of the interval of their smoothing by the desired function (temperature). The discontinuous coefficients are replaced by bounded smooth temperature functions. For the numerical solution, the finite difference method and the finite element method with an automated selection of the smearing and smoothing parameters for the coefficients at each time layer are used. The results of numerical calculations are compared with the solution of Stefan’s two-phase self-similar problem --- with a mathematical model of the formation of the ice cover of the reservoir. Numerical simulation of the thawing effect of installing additional piles on the existing pile field is carried out. The temperature on the day surface of the base of the structure is set with account for the amplitude of air temperature fluctuations, taken from the data of the Yakutsk meteorological station. The study presents the results of numerical calculations for concrete piles installed in the summer in large-diameter drilled wells using cement-sand mortars with a temperature of 25 °С. The distributions of soil temperature are obtained for different points in time

Erosion-corrosion of an Aluminum Alloy in Two Phase Jet Flow

1994 ◽  
Vol 43 (4) ◽  
pp. 194-199 ◽  
Author(s):  
Hiroshi Nanjo ◽  
Norio Sanada ◽  
Kazuo Koike
Keyword(s):  
Aluminum Alloy ◽  
Jet Flow ◽  
Two Phase ◽  
Erosion Corrosion

scholarly journals EFFECT OF PARTICLE CONCENTRATION ON TURBULENCE CHARACTERISTICS OF 2-D SOLID-LIQUID TWO-PHASE JET FLOW

1998 ◽  
Vol 42 ◽  
pp. 1177-1182
Author(s):  
Yasuo NIHEI ◽  
Kazuo NADAOKA ◽  
Noriyasu NAKAMURA
Keyword(s):  
Particle Concentration ◽  
Jet Flow ◽  
Two Phase ◽  
Turbulence Characteristics ◽  
Solid Liquid

STUDY OF FLOW STRUCTURE IN THE AERATION TANK INDUCED BY TWO PHASE JET FLOW(Multiphase Flow)

2005 ◽  
Vol 2005 (0) ◽  
pp. 229-234
Author(s):  
Kosuke Ode ◽  
Toshihiro Ohmae ◽  
Kenji Yoshida ◽  
Isao Kataoka
Keyword(s):  
Multiphase Flow ◽  
Flow Structure ◽  
Jet Flow ◽  
Aeration Tank ◽  
Two Phase

scholarly journals Reply to “Comments on ‘MSE minus CAPE is the True Conserved Variable for an Adiabatically Lifted Parcel’”

2016 ◽  
Vol 73 (6) ◽  
pp. 2577-2583
Author(s):  
David M. Romps
Keyword(s):  
Triple Point ◽  
Specific Energy ◽  
Liquid Water ◽  
Thermodynamic System ◽  
Numerical Calculations ◽  
Two Phase ◽  
Point Temperature ◽  
Dry Air ◽  
Temperature And Pressure ◽  
Triple Point Temperature

Abstract A standard convention in moist thermodynamics, adopted by D. M. Romps and others, is to set the specific energy and entropy of dry air and liquid water to zero at the triple-point temperature and pressure. P. Marquet claims that this convention leads to physically incorrect results. To support this claim, Marquet presents numerical calculations of a lifted parcel. It is shown here that the claim is false and that the numerical calculations of Marquet are in error. In the context of a simple two-phase thermodynamic system, an analysis is presented here of the freedoms one has to choose additive constants in the definitions of energy and entropy. Many other misconceptions are corrected as well.

scholarly journals Comparison of different CFD software performances in the case of an incompressible air flow through a straight conical diffuser

2017 ◽  
Vol 21 (suppl. 3) ◽  
pp. 863-874
Author(s):  
Djordje Novkovic ◽  
Jela Burazer ◽  
Aleksandar Cocic
Keyword(s):  
Mathematical Modeling ◽  
Technological Development ◽  
Pulverized Coal ◽  
Thermal Engineering ◽  
Two Phase ◽  
Greenhouse Gases Emissions ◽  
Numerical Studies ◽  
Fluid Jets ◽  
History Of ◽  
Flow Through

Paper gives a review of the most important results of turbulence research achieved by the Laboratory for Thermal Engineering and Energy at the Vinca Insitute of Nuclear Sciences. Paper presents detailed overview of the history of the scientific research provided in the laboratory, from the beginning in the mid-60s to today, pointing out the main reasons initiating the investigations in this field. After the first period, which was mainly devoted to the research of the structure of the turbulence, since the beginning of the 80s, research is mainly oriented to the flows at high temperatures including chemical reactions and to the development and improvement of differential mathematical models as a modern and very efficient tool in the technological development. This research significantly contributed to the development of pulverized coal burners, plasma-chemical reactors, and optimization of pulverized coal fired boilers operating parameters and prediction of the greenhouse gases emissions. Most recent period includes experimental and numerical studies of the coherent structures in turbulent fluid jets, mathematical modeling of various turbulent thermal flow processes including two-phase turbulent flow in the multiphase heat exchangers and mathematical modeling of the atmospheric boundary layer.

scholarly journals Numerical simulation of the effect of different NaCl concent on boiler flame combustion process

2021 ◽  
Vol 2108 (1) ◽  
pp. 012097
Author(s):  
Zhihai Cheng ◽  
Jiahao Wang ◽  
Xinhai Han
Keyword(s):  
Alkali Metal ◽  
Radiation Heat Transfer ◽  
Combustion Process ◽  
Pulverized Coal ◽  
Combustion Model ◽  
Two Phase ◽  
Combustion Region ◽  
Zhundong Coal ◽  
High Alkali ◽  
Factsage Software

Abstract Zhundong coal has been widely concerned because of its high alkali metal content, which brings great danger to the combustion of boiler. Therefore, it is extremely necessary to study the laws and characteristics of alkali metal influencing combustion in the burning process of zhundong coal. A gas-solid two-phase flow combustion model of pulverized coal containing NaCl was established by using Fluent software and FactSage software in a hot experimental combustion furnace. The influence of different NaCl content in pulverized coal on pulverized coal combustion process was discussed. The results show that with the increase of NaCl content in pulverized coal from 0 to 1% and 2%, the flame center temperature in the furnace increases about 80°C and 120°C under the same coal content, so it can be concluded that the increase of NaCl content can promote the combustion process of pulverized coal in the furnace. At the same time, it can be calculated that, with the increase of NaCl content, the flame range of the combustion region inside the furnace increases by 1/3. Because NaCl is decomposed by heat during combustion to help combustion, and the radiation heat transfer increases, the flame radiation range inside the furnace will increase.

scholarly journals Numerical analysis of the flue gas-coal particles mixture flow in burner's distribution channels with regulation shutters at the TPP Nikola Tesla - A1 utility boiler

2010 ◽  
Vol 14 (2) ◽  
pp. 505-520 ◽  
Author(s):  
Nikola Zivkovic ◽  
Dejan Cvetinovic ◽  
Milic Eric ◽  
Zoran Markovic
Keyword(s):  
Flue Gas ◽  
Concentration Distribution ◽  
Distribution Channels ◽  
Pulverized Coal ◽  
Two Phase ◽  
Mixture Flow ◽  
Outlet Cross Section ◽  
Plasma Torches ◽  
Coal Particles ◽  
Nikola Tesla

Pulverized coal particles concentration distribution across the burner's distribution channels, especially where plasma torches are installed, is one of the key issues for efficient implementation of plasma system for liquid fuel free combustion support at the pulverized coal fired boilers. The possibility of pulverized coal particles concentration increase at the lower burner channels of TPP Nikola Tesla - A1 boiler using regulation shutters is analyzed experimentally and numerically. Subject of present work is two-phase flue gas-particles mixture flow in burner's distribution channels with regulation shutters installed at the TPP Nikola Tesla - A1 boiler. Aim of this work is to optimize position of implemented system of shutters to achieve desired concentration and velocity distribution in channels with plasma torches, using numerical modelling. Experimental investigation was performed for the verification of proposed mathematical model for the prediction of the analyzed two-phase flow. Based on verified model, numerical parametric analysis was done. Obtained results of gas phase velocity field, coal particles concentration field, velocity and concentration profiles clearly show the dependence between shutters position and the coal particles mass flow rate and concentration distribution at the outlet cross-section of the burner's distribution channels. According to the numerical optimization results suitable modification of the shutter system is proposed.

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