Search results

Simulation investigation on Structural Parameter of Hot Air Igniter of Biomass Cui Yongzhang1,2,a *, Tang Mingtian1,b, Zhang Linhua1,2,c, Gao Peng1,d, Zhang Guokai1,e, 1.
Key Laboratory of Building Renewable Energy Utilization Technologies, Shandong Jianzhu University, Ministry of Education, Jinan 250101, China acyz@sdjzu.edu.cn, btangmt91@163.com, czhth0015@sdjzu.edu.cn, d13705319853@126.com, e13964060604@163.com Keywords: Hot air, igniter, biomass, pellet Abstract: In view of rich resources of corn stalks, cotton stalks forming pellets hot ignition performance, using CFD numerical simulation analysis to study the key parameters of electric ignition such as the surface ignition temperature, air velocity, air flow distribution ratio of influence of hot air outlet temperature.
In this paper, using CFD to simulate key parameters of electrically heated hot air ignition, provide the basis for straw biomass pellet fuel ignition.
Inside and outside circulation area ratio , Ainner/Aouter Keep Ainner constant ,by changing the outside area Aouter by increasing the diameter of igniter to get a different Ainner/Aouter , the simulation results under the same Vair are shown in figure 5 and 6.In figure 5，with the increasing of Ainner/Aouter ,the outlet temperature of hot air first increase then decrease ,thus the best Ainner/Aouter is between 1.8 to 2.2 .
Conclusions Through the numerical simulation of the structural parameters of hot air igniter and the ignition experiments to obtain the following conclusions: 1) Improving the heating surface temperature , reducing the air velocity and convective heat transfer coefficient of the external tube could significantly increase the hot air temperature ,and reduce the ignition timing .Therefore the temperature of the hot air should not be below 450℃ 2) The circulation area of internal and external of igniter ratio should be controlled between 1.8-2.2 to ensure the best air flow ratio.

CFD Analysis of Temperature Imbalance in Full Scale Tangentially Fired Coal Boiler Siti Sarah Ain Fadhila, Hasril Hasini and Mohd Nasharuddin Mohd Jaafar Universiti Tenaga Nasional, Jalan IKRAM-UNITEN, 43000 Kajang, Selangor, Malaysia asitisarah@uniten.edu.my, Keyword: coal, tangentially fired, temperature imbalance, computational fluid dynamics Abstract: Tangentially fired boilers are widely used in generating electricity power due to its advantage of distributing heat evenly to all furnace walls.
Currently, most of the existing studies concentrated on analysing the temperature imbalance at furnace exit and simulations are done at design condition.
Fig. 1: Front view of furnace with air and fuel arrangement Fig. 2: Tangential fired arrangement Mesh Generation Mesh generation is important in order to have a good quality of simulation.
Boosroh: Analysis of Flow and Temperature Distribution in a Full Scale Utility Boiler Using CFD, Proceeding of ICEE 2009 3rd International Conference on Energy and Environment, Malacca.(2009)

S.Som[5] and the others proposed a new primary atomization model that is KH-ACT model which considered influence of aerodynamic effects, turbulent and cavitation and numerical simulation results were closer to those from the test;Berg[6] used three-dimension model to simulation two-phase flow in nozzles and coupled the data at the nozzle outlet from simulations with primary atomization model considering of cavitation.At present, study of primary atomization is far from enough,with both experimental way and numerical simulation.In this paper,the turbulence and cavitation in nozzle flow were coupled to simulate spray and different primary atomization model were analyized and evaluated though numerical simulation with them and then influence factors on primary atomization were analyized.
Fig. 1 Grid calculation Initial and boundary conditions of Spray simulation are as table 1: Table 1 Parameter sign unit number Cylinder pressure P Pa 374755 Cylinder sir density kg /m3 1.19 Cylinder temperature T K 340.6 Turbulence kinetic energy TKE m 2/s2 30 Turbulence length scales TLS m 0.0075 Start crank angle ° 360 End crank angle ° 397 Nozzle diameter D m 1.95×10-4 Injection mass M kg 2.76×10-5 Three-dimension CFD model of cavitating and turbulent flow in the nozzle There are six symmetrical holes of the nozzle and one half of the hole was selected for simulation,so the sector zone of 30 degree of the nozzle was selected for generating grid,as shown in Fig.2.
In the future the following several aspects of primary atomization will be paid more attention to :(1) advanced visualization experiment devices must be used to get the detailed structure of intalt liquid core in primary atomization.(2) new precise primary break-up model which consider aerodynamic effects, turbulence and cavitation must be setup and be input to CFD spray models for getting more actual spray simulation.
Coupled simulations of nozzle flow, primary fuel jet break-up and spray Formation, J.
Vertical porous nozzle internal hole two phase flow of three dimensional numerical simulation analysis [J ] .

Three-dimensional model and computational fluid dynamical (CFD) model for flow filed analysis are established.
Fig.1 Structure of ordinary-gear-train based screen pipe Computational Fluid Dynamics (CFD) of the Screen Pipe Structural Parameters of Screen Pipe.
Fig. 2 Geometric model Fig. 3 Mesh of the blades Fig. 4 Mesh of the screen pipe CFD Analysis.
CFD analysis is based on the conservation of mass, momentum and energy.
The simulation of the flow field discloses the mechanism of the dynamical-filtering screen pipe. 2.

Based on the case, this paper introduced a CFD method to heat the diesel fuel to reduce fuel viscosity and surface tension, expecting to explore the in-cylinder combustion process and emissions generation, so that the atomization effect of fuel spray and combustion in diesel could be improved.
Use CFD to elaborate the effects on emission and combustion process by using high temperature fuel.
Simulation of the combustion process begins from 120°CA before top dead centre to 120° CA after TDC.
Optimization of a simplified sub-model for NO emission prediction by CFD in large 4-stroke marine diesel engines [J].
[4] Yan Ping, Feng Mingzhi,Ping Tao,et al.Simulation research on effect of nozzle parameters on combustion and emissions for HPCR marine diesel engine[J].

Modelling Approach The modelling CFD includes three stage which is pre-processing, solver and post processing using ANSYS-CFX 14.
As the real geometry for CO2 leakage model has a very high dimension, it will require a high number of meshes and long simulation time.
Results and Discussion The base case model has been simulated for simulation time 50 days, 100 days, 300 days, 500 days, and 1000 days using transient analysis.
To predict the potential of CO2 leakage, the simulation results has been plotted into logarithmic graph with a yearly timescale.
The CFD result also being compared with experiment data from Barlet Gouedard supercritical CO2 and saturated data [3] and Kutchko saturated brine [2].

In the process ANSYS2FLOTRAN CFD program is applied.
All sides of the chamber keep radiating heat. 3.Finite element method ANSYS-FLOTRAN CFD is an advanced tool used to analyze the two and three dimensional flowing fields[2].
It usually includes three steps as follows: model building, loads applying and equation solving. 3.1model building (1) Analysis type choice:Choose the analysis function of ANSYS-FLOTRAN CFD
Fig.7 shows the change curve of actually metrical bridge voltage ∆U with acceleration. 0.0 0.1 0.2 0.3 0.4 0.5 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 a/(g) B v0/(v) Fig.7 Relation between outputt voltage of sensor and acceleration 6.Conclusions Using the finite element method and ANSYS-FLOTRAN CFD program,the temperature field is calculated in different acceleration.The calculation results and analysis results show: (1) The temperature difference between two thermistors changes with the acceleration change
[2] Guoqiang Wang, Numerical simulation and practice on ANSYS [M], Xi'an: Northwest Industry University Press, 1999. 221

China 2State Key Laboratory of Automotive simulation and Control, Jilin University Changchun, R.P.
Today CFD is an important tool for engineers in the automotive industry.
Then solid - liquid coupled heat transfer analysis is done by using CFD software FLUENT.
Basic research of engine coolant flow three-dimensional numerical simulation [J].
[4] Okumura, CFD Simulation by Automatically Generated Tetrahedral and Prismatic Grid for Engine Intake Duct and Coolant Flow in Three Days [C].SAE 2000-01-0294.

To achieve the objectives, computational fluid dynamics (CFD) and the Ansys CFD® software were used.
Consisting of 337,360 hexahedral elements, the computational mesh was built using the Ansys ICEM CFD® software.
Experimental and simulation of a novel hydrocyclone-tubular membrane as overflow pipe.
Lead/air separation process using cyclonic separator: modeling and simulation.
Computational Fluid Dynamics Simulation of Membrane Separation Processes.

This ensures the correctness of simulation.
For the similarity in structure of V-cone and double-cones studied in paper, the author based on formula form of V-cone expansibility factor and amounts of experiments, doping out the expansibility factor rule of the double-cones meter by CFD.
Numerical Simulation Research Structure and Modeling.
Fig.7 Comparison expansibility factor of the double-cones with other flow-meters Summary The paper conducts a mass of numerical simulation on the double-cones meter with β as 0.4, {TTP}12289 0.5, {TTP}12289 0.6, {TTP}12289 0.7, {TTP}12289 0.8 and 0.9 by CFD, obtaining a prediction formula of the expansibility factor, what’s more, comparing it with other flow-meters.
Experimental Study and Computational Simulation on the Double-cones Flow-meter[J].