Numerical Simulation of Different Coal Combustion in Two Tiny-Oil Ignition Burners With Oxygen-Enriched

2012 ◽  
Author(s):  
Yongsheng Zhang ◽  
Haisu Wu ◽  
Xueqi Liu ◽  
Chenn Qian Zhou ◽  
Zhongguang Fu
Keyword(s):  
Numerical Simulation ◽  
High Temperature ◽  
Coal Combustion ◽  
Bituminous Coal ◽  
The Other ◽  
Temperature Zone ◽  
Heating Value ◽  
Oxygen Burner ◽  
High Volatility ◽  
Simulation Results

Two tiny-oil ignition combustion burners with oxygen-enriched were studied in this paper. One is adding oxygen directly into primary air, and the other is adding oxygen by extra adding-oxygen tube. The bituminous coal, the lignite, and the meager coal, are simulated in these burners. By comparing the two different combustion characteristics, the simulation results show that, for bituminous coal, the high temperature zone congregates in the first directly added oxygen burner, while, for the meager coal, it is difficult to burn in the first directly added oxygen burner. As to the lignite, because of its characteristics of high volatility and low heating value, the first directly added oxygen burner provide oxygen timely for its high volatile, its flame combust more quickly and directly.

Numerical Simulation of Temperature for Al2O3 Ceramics during Micro-Detonation of Arc Strike Machining

2012 ◽  
Vol 429 ◽  
pp. 3-8
Author(s):  
Xin Li Tian ◽  
Ke Ling Lin ◽  
Bao Guo Zhang ◽  
Chun Fang Xue ◽  
Jian Quan Wang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
High Temperature ◽  
Theoretical Model ◽  
Pulse Width ◽  
Processing Parameters ◽  
Ansys Software ◽  
Temperature Zone ◽  
Simulation Results ◽  
Element Theory

A theoretical model of temperature for Al2O3ceramics during micro-detonation of arc strike machining was established. Based on finite element theory, the temperature of Al2O3ceramics during micro-detonation of arc strike machining was simulated with the aid of Ansys software, combined with the actual processing, the width and depth of cavity impacted by micro-detonation were calculated. The simulation results show that the highest temperature of Al2O3ceramics is over 13435 °C in a given processing parameters, while the high-temperature zone is quite small. With the increase of pulse width and electricity, the temperature within the machined zone increases rapidly, but the outside area kept a low temperature; and with the increase of nozzle radius, the diameter to depth ratio of the distribution of temperature is increasing gradually. The data gained from the simulation is proved to be accordant with the data gained from experiments.

Modeling Recrystallization for 3D Multi-Pass Forming Processes

2007 ◽  
Vol 558-559 ◽  
pp. 1201-1206 ◽  
Author(s):  
Mihaela Teodorescu ◽  
Patrice Lasne ◽  
Roland E. Logé
Keyword(s):  
Numerical Simulation ◽  
Grain Size ◽  
Present Model ◽  
Static Recrystallization ◽  
Volume Fraction ◽  
The Other ◽  
Finite Element Code ◽  
3D Numerical Simulation ◽  
Fraction Distribution ◽  
Simulation Results

The present work concerns the simulation of metallurgical evolutions in 3D multi-pass forming processes. In this context, the analyzed problem is twofold. One point refers to the management of the microstructure evolution during each pass or each inter-pass period and the other point concerns the management of the multi-pass aspects (different grain categories, data structure). In this framework, a model is developed and deals with both aspects. The model considers the microstructure as a composite made of a given (discretized) number of phases which have their own specific properties. The grain size distribution and the recrystallized volume fraction distribution of the different phases evolve continuously during a pass or inter-pass period. With this approach it is possible to deal with the heterogeneity of the microstructure and its evolution in multi-pass conditions. Both dynamic and static recrystallization phenomena are taken into account, with typical Avrami-type equations. The present model is implemented in the Finite Element code FORGE2005®. 3D numerical simulation results for a multi-pass process are presented.

The Proposal of Wall Thickness Management Criteria of T-Pipes

2012 ◽  
Author(s):  
Kiyoharu Tsunokawa ◽  
Taku Ohira ◽  
Naoki Miura ◽  
Yasumi Kitajima ◽  
Daisuke Yoshimura
Keyword(s):  
Numerical Simulation ◽  
Wall Thickness ◽  
Parametric Study ◽  
The Other ◽  
Wall Thinning ◽  
Study Results ◽  
Simulation Results ◽  
Design Construction

Although the reinforcement for openings is checked in accordance with design / construction standard when thinning was observed in T-pipes, this evaluation becomes too conservative or requires much time and effort. This paper describes additional parametric study results and proposes a guideline for thickness management of wall thinning T-pipes. On the other papers related to this project, the experiment and numerical simulation results are reported. This paper referred these results and performed further investigation.

Numerical Simulation of High-Temperature Air Direct-Ignition of Pulverized Coal

2005 ◽  
Author(s):  
Z. Z. Kang ◽  
B. M. Sun ◽  
Y. H. Guo ◽  
W. Zhang ◽  
H. Q. Wei
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
High Temperature ◽  
Simulation Method ◽  
Pulverized Coal ◽  
Inlet Velocity ◽  
Operation Optimization ◽  
Structure Improvement ◽  
Simulation Results ◽  
Direct Ignition

Numerical simulation method is employed in this article to investigate various high-temperature air direct-ignition processes of pulverized coal (PC). Several important factors are analyzed, which are the inlet velocity of primary air flow, PC concentration and the velocity and temperature of high temperature air. The flow, combustion and heat transfer in high temperature air oil-free ignition burner can also be obtained from the simulation results, which are in accordance with the experimental data. The research provides guidance for structure improvement and operation optimization of burner.

Modeling and Simulation of a Stand-Alone Hydrogen Photovoltaic Fuel Cell Hybrid System

2014 ◽  
pp. 829-859
Author(s):  
M.T. Benmessaoud ◽  
A. Boudghene Stambouli ◽  
M. Tioursi
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Power Generation ◽  
High Temperature ◽  
Fuel Cell ◽  
Hydrogen Generation ◽  
Storage System ◽  
Storage Unit ◽  
Pv Array ◽  
Simulation Results

In this Chapter, a hybrid Photovoltaic-Fuel Cell (PV-FC) generation system employing an electrolyser for hydrogen generation is designed and simulated. The system is applicable for remote areas or isolated loads. This system has been simulated via a developed general dynamic mathematical model which analytically describes the electric subsystems. Some interesting simulation results are presented in this chapter. Specific attention is paid to the investigation of the dynamic analysis of the photovoltaic, fuel cell, and electrolyser system at the connection. The objective of this study is to evaluate the performance of an autonomous stationary power generation and thermal coupling a PV array and a storage system for hydrogen, consisting of an electrolyser, a storage unit of gas, and a fuel cell of high temperature. Hydrogen is the only means that stores electricity. Stationary applications of a few kilowatts are evaluated by numerical simulation in MATLAB/SIMULINK.

Numerical Simulations on Assembly Modifications for Annular Casing of One Centrifugal Pump

2012 ◽  
Vol 516-517 ◽  
pp. 966-969
Author(s):  
Yi Zhang Fan ◽  
Zhi Gang Zuo ◽  
Shu Hong Liu ◽  
Yu Jun Sha ◽  
Yu Lin Wu
Keyword(s):  
Numerical Simulation ◽  
High Pressure ◽  
High Temperature ◽  
Numerical Simulations ◽  
Centrifugal Pump ◽  
Radial Force ◽  
Hydraulic Efficiency ◽  
Centrifugal Pumps ◽  
Safety Factors ◽  
Simulation Results

Centrifugal pumps adopt annular casings instead of volute casings when working in high temperature and high pressure conditions, which results in conservative safety factors in sacrifice of hydraulic efficiency. This paper presents numerical simulations on two assembly modification methods for one annular casing imitating the volute casing to improve hydraulic performance. Method one was the eccentric axis method. Method two was the extended vane method. Numerical simulation results, given by CFX, showed that both the two method could increase the hydraulic efficiency and head while rise in radial force was small.

Origin of Leakage Currents in ZnO Based Varistor Ceramics with Al(NO3)3 Dopant

2010 ◽  
Vol 434-435 ◽  
pp. 386-388 ◽  
Author(s):  
Jun Hu ◽  
Wang Chen Long ◽  
Jin Liang He ◽  
Jun Liu ◽  
Feng Chao Luo
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Electrical Properties ◽  
Grain Boundaries ◽  
The Other ◽  
Leakage Currents ◽  
Donor Density ◽  
Zno Varistor ◽  
Zno Varistors ◽  
Simulation Results

The additive of Al(NO3)3 has been doped into ZnO varistors in order to reduce their residual voltages. However, the leakage currents of samples always increase at the same time. Generally, it is recognized that some of doped Al3+ ions enter the ZnO grains and reduce their resistivity, which results in lower residual voltages of varistor samples. On the other hand, the remnant Al3+ ions appear in the grain boundaries and also reduce their resistivity, which results in larger leakage currents. In this paper, the electrical properties of ZnO varistor samples with various amounts of Al(NO3)3 dopant were measured. The experimental data are compared with the numerical simulation results, which reveals that the increased leakage currents of ZnO varistors with Al(NO3)3 dopant are not only due to the decreased resistivity of grain boundaries, but also the increased donor density of ZnO grains.

Modeling and Simulation of a Stand-Alone Hydrogen Photovoltaic Fuel Cell Hybrid System

2017 ◽  
pp. 545-580 ◽  
Author(s):  
M.T. Benmessaoud ◽  
A. Boudghene Stambouli ◽  
M. Tioursi
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Power Generation ◽  
High Temperature ◽  
Fuel Cell ◽  
Hydrogen Generation ◽  
Storage System ◽  
Storage Unit ◽  
Pv Array ◽  
Simulation Results

In this Chapter, a hybrid Photovoltaic-Fuel Cell (PV-FC) generation system employing an electrolyser for hydrogen generation is designed and simulated. The system is applicable for remote areas or isolated loads. This system has been simulated via a developed general dynamic mathematical model which analytically describes the electric subsystems. Some interesting simulation results are presented in this chapter. Specific attention is paid to the investigation of the dynamic analysis of the photovoltaic, fuel cell, and electrolyser system at the connection. The objective of this study is to evaluate the performance of an autonomous stationary power generation and thermal coupling a PV array and a storage system for hydrogen, consisting of an electrolyser, a storage unit of gas, and a fuel cell of high temperature. Hydrogen is the only means that stores electricity. Stationary applications of a few kilowatts are evaluated by numerical simulation in MATLAB/SIMULINK.

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