scholarly journals Effect of the Preheating Inlet Air on the G222 Fuel Combustion

2019 ◽  
Vol 3 (2) ◽  
pp. 29
Author(s):  
Mohammed El Hadi Attia
Keyword(s):  
Numerical Simulation ◽  
Carbon Monoxide ◽  
Axial Velocity ◽  
Mass Fraction ◽  
Three Dimensional ◽  
Special Treatment ◽  
Inlet Temperature ◽  
Governing Equations ◽  
Characteristic Parameters ◽  
Air Inlet

In this paper, a numerical simulation is developed to study the preheating effect of the air in a three-dimensional cylindrical combustion chamber using the FLUENT-CFD code. Particularly, we are interested on the calculation of the characteristic parameters such as the axial velocity, the temperature and the mass fraction of carbon monoxide. This study consists of a special treatment of mathematical models. The considered approaches resolve the governing equations of system. The main objective of this work is to study the behavior of the parameters considered previously during the variation of the air inlet temperature. The obtained results show that the variation of the inlet temperature presents a direct effect on the considered parameters. 

scholarly journals Evaporation Characteristics of Spray in a Lean Premixed-Prevaporization Combustor for a 100 KW Automotive Ceramic Gas Turbine

1994 ◽  
Author(s):  
Youichlrou Ohkubo ◽  
Yoshinorl Idota ◽  
Yoshihiro Nomura
Keyword(s):  
Gas Turbine ◽  
Mass Fraction ◽  
Liquid Fuel ◽  
Three Dimensional ◽  
Flame Stabilization ◽  
Fuel Spray ◽  
Inlet Temperature ◽  
Lean Combustion ◽  
Swirl Chamber ◽  
Lean Premixed

Spray characteristics of liquid fuel air-assisted atomizers developed for a lean premixed-prevaporization combustor were evaluated under two kinds of conditions: in still air under non-evaporation conditions at atmospheric pressure and in a prevaporization-premixing tube under evaporation conditions with a running gas turbine. The non-evaporated mass fraction of fuel spray was measured using a phase Doppler particle analyzer in the prevaporization-premixing tube, in which the inlet temperature ranged from 873K to 1173K. The evaporation of the fuel spray in the tube is mainly controlled by its atomization and distribution. The NOx emission characteristics measured with a combustor test rig were evaluated with three-dimensional numerical simulations. A low non-evaporated mass fraction of less than 10% was effective in reducing the exhausted NOx from lean premixed-prevaporization combustion to about 1/6 times smaller than that from lean diffusion (spray) combustion. The flow patterns in the combustor are established by a swirl chamber in fuel-air preparation tube, and affect the flame stabilization of lean combustion.

scholarly journals Three-dimensional numerical simulation of a turbulent flow around an obstacle

2020 ◽  
Vol 307 ◽  
pp. 01006
Author(s):  
Benahmed Lamia ◽  
Aliane Khaled ◽  
Z. Sari Hassoun
Keyword(s):  
Numerical Simulation ◽  
Velocity Field ◽  
Kinetic Energy ◽  
Three Dimensional ◽  
Governing Equations ◽  
Ansys Cfx ◽  
Recirculation Zones ◽  
Rectangular Obstacle ◽  
Volume Method ◽  
Calculation Code

In this work we study the influence of the inclined shape of the lover and downstream edge of a rectangular obstacle. We analyze the dimensions of the recirculation zones, the velocity field, the kinetic energy and the pressure. A three-dimensional study was conducted using the ansys cfx calculation code. The turbulence model k-ԑ is used to model turbulence, and the governing equations are resolved by the finite volume method.

scholarly journals The Effects of Air Preheating and Fuel/Air Inlet Diameter on the Characteristics of Vortex Flame

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Mostafa Khaleghi ◽  
S. E. Hosseini ◽  
M. A. Wahid ◽  
H. A. Mohammed
Keyword(s):  
Flame Temperature ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Flame Stability ◽  
Constant Mass ◽  
Governing Equations ◽  
Pollutant Formation ◽  
First Order ◽  
Air Inlet ◽  
Energy Equations

The effects of fuel/air inlet diameter as well as air preheating on the flame stability, temperature distribution, pollutant formation, and combustion characteristics of a lab-scaled asymmetric vortex flame have been investigated. A three-dimensional steady-state finite volume solver has been used to solve the governing and energy equations. The solver uses a first-order upwind scheme to discretize the governing equations in the space. The semi-implicit method for pressure linked equations has been applied to couple the pressure to the velocity terms. Several turbulence models were applied to predict the flame temperature and it was found thatk-εRNG has given the best results in accordance with the experimental results. The results reveal that the inlet air diameter can enhance the thermal properties and reduce theNOxemission while the inlet fuel diameter has less significant impact. Increasing diameters are accompanied with a pressure drop. It was found that preheating the air and fuel would significantly affect the flame temperature andNOxemission with constant mass flow rate.

Numerical Simulation of Oscillating Heat Pipe Heat Exchanger

2010 ◽  
Vol 6 (1) ◽  
Author(s):  
Benyin Chai ◽  
Min Shao ◽  
Xuanyou Li ◽  
Shenjie Zhou ◽  
Yongchun Shi
Keyword(s):  
Numerical Simulation ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Pipe ◽  
High Efficiency ◽  
Inlet Temperature ◽  
Oscillating Heat Pipe ◽  
Air Inlet ◽  
Hot Air ◽  
Pipe Heat

Oscillating heat pipe is a new type high efficiency heat-transfer element. Its development and design attract increasing attention. This paper describes a numerical simulation for investigating on the flow and heat exchange performance of an oscillating heat pipe heat exchanger. The influences of the arrangement of heat pipe, the inlet temperature and the flux of hot air were explored. The results show that the heat exchange of staggered arrangement is more efficient than the aligned one. The influence of temperature difference on the heat exchanger by hot air flux is more than hot air inlet temperature.

Numerical Simulation of Buoyancy Affected Turbulent Air Flow in a Room

2006 ◽  
Author(s):  
A. Nouri-Borujerdi ◽  
A. Fathi-Gishnegani
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
System Performance ◽  
Turbulence Modeling ◽  
Air Flow ◽  
Three Dimensional ◽  
Governing Equations ◽  
Single Room ◽  
Turbulent Air Flow ◽  
Radiator System

In this paper a three-dimensional steady state incompressible turbulent air flow is considered in a large single room. The buoyancy affected turbulent air flow is simulated by solving governing equations numerically. The turbulence modeling includes both k–ε and zero-equation models and their results are compared to the experimental data. The paper reviews several aspects such as displacement of radiator system performance, temperature and flow field distribution and comfort. The results show that the best temperature distribution and comfort obtain when radiator is installed under the window and its height be equal to or greater than that of the window.

Three-dimensional numerical simulation of air flow and fiber dynamic in carding region in carding machine

2019 ◽  
Vol 89 (19-20) ◽  
pp. 3916-3926
Author(s):  
Shanshan He ◽  
Longdi Cheng ◽  
Wenliang Xue ◽  
Zhong Lu ◽  
Liguo Chen
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Finite Element ◽  
Flow Field ◽  
Axial Velocity ◽  
Three Dimensional ◽  
Tangential Velocity ◽  
Element Model ◽  
Mechanical Analysis ◽  
Field Simulation

Regular cylinder metallic card clothing has a limited carding efficiency. As a result of the limited dimensions, any measurement between the cylinder and flat area is difficult to make. In this study, an approach is first proposed to simulate the flow field and a fiber finite-element model on the moving surface of the teeth and produce a new design of misaligned-teeth card clothing, with the aim of improving the carding efficiency. A comparison is made between regular and misaligned-teeth card clothing types with respect to flow field simulation and fiber mechanical properties. The results show that the force resulting from the tangential velocity between the cylinder and flat is as great as 1.86 × 10−3 N, sufficient to pull fiber out of tufts, and that the tangential velocity (from 3880 to 2500 mm/s) plays a major role in this area, as opposed to the axial velocity (from 0 to 190 mm/s). Through this comparison, the misalignment design can result in a different tangential velocity distribution from that of traditional card clothing, which helps fibers between two lines of teeth move into neighboring lines of teeth, thereby increasing the likelihood that fibers will be carded. For fiber mechanical analysis, different air forces are loaded on fibers. This comparison shows that for fibers in the channel, the misalignment can help fibers move toward the teeth. Therefore, this misaligned-teeth card clothing is thought to prove more effective in practice.

Experimental and Numerical Investigations of Subcooled Boiling Heat Transfer in a Small-Diameter Tube

2020 ◽  
Vol 12 (6) ◽  
Author(s):  
Makoto Shibahara ◽  
Qiusheng Liu ◽  
Koichi Hata ◽  
Katsuya Fukuda
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Flux ◽  
Boiling Heat Transfer ◽  
Fluid Model ◽  
Three Dimensional ◽  
Small Diameter ◽  
Inlet Temperature ◽  
Simple Method ◽  
Subcooled Water

Abstract The boiling heat transfer for subcooled water flowing in a small-diameter tube was investigated experimentally and numerically. In the experiment, a platinum tube was used as an experimental tube (d = 1.0–2.0 mm) to conduct joule heating by direct current. The heat generation rate of the tube was controlled with an exponential function. The numerical simulation of boiling heat transfer for subcooled water flowing in the small-diameter tube was conducted using the commercial computational fluid dynamics (CFD) code, phoenics ver. 2013. The small-diameter tube was modeled in the simulation. As the boundary condition, the measured heat flux was given at the inner wall. The inlet temperature ranged from 302 to 312 K. The flow velocities of d = 1.0 mm and d = 2.0 mm were 9.29 m/s and 2.34 m/s, respectively. The three-dimensional analysis was carried out from non-boiling to the critical heat flux (CHF). Governing equations were discretized using the finite volume method in the phoenics. The semi-implicit method for pressure linked equation (SIMPLE) method was applied in the numerical simulation. For modeling boiling phenomena in the tube, the Eulerian–Eulerian two-fluid model was adopted using the interphase slip algorithm of phoenics. The surface temperature difference increased as the heat flux increased in the experiment. The numerical simulation predicted the experimental data well. When the heat flux of the experiment reached the CHF point, the predicted value of the heat transfer coefficient was approximately 3.5% lower than that of the experiment.

Numerical Simulation of Three-Dimensional Supercritical Water Flows in Hydrothermal Synthesis Reactors With Arbitrary Geometry

2015 ◽  
Author(s):  
Takashi Furusawa ◽  
Shibo Qi ◽  
Satoru Yamamoto
Keyword(s):  
Numerical Simulation ◽  
Hydrothermal Synthesis ◽  
Flow Reactor ◽  
Rapid Change ◽  
Three Dimensional ◽  
Inlet Temperature ◽  
Buoyancy Effect ◽  
Arbitrary Geometry ◽  
Counter Flow ◽  
Water Flows

Numerical simulations of mixing flows of supercritical (SC) water and water liquid in a 3-D T-shaped circular pipe and a 3-D cross pipe are conducted using the numerical method developed by our group. The 3-D geometry is generated by Building-Cube Method (BCM) with the stepwise wall treatment. Numerical results of mixing flows in the two pipes are compared and the effect of the inlet temperature is evaluated. In the T-shaped circular reactor, the mixing is periodic and a vortex is observed at the mixing point. The mixing form certainly depends on the SC water temperature. In the counter flow reactor, the SC water flow becomes unsteady and is mixed with water liquid asymmetrically due to the rapid change of thermophysical properties and the buoyancy effect.

Numerical Simulation and Optimization of Air Distribution in Large Space

2014 ◽  
Vol 1070-1072 ◽  
pp. 2021-2026
Author(s):  
Ze Hang Du ◽  
Chun Hua Liu ◽  
Guang Zhou
Keyword(s):  
Numerical Simulation ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Large Space ◽  
Air Conditioning System ◽  
Simulation And Optimization ◽  
Air Inlet ◽  
Air Supply ◽  
Dimensional Distribution ◽  
Air Speed

In recent years, people pay increasing attention to the issue whether indoor air conditioning system can meet the requirements of thermal comfort under the circumstance of good air quality and reduce energy consumption. FLUENT, commercial computational fluid dynamics software is used to simulate the three-dimensional distribution of temperature and velocity in the subject hotel atrium. The turbulence model modified by buoyancy was used to solve equations. The SIMPLE scheme was used for numerical discrimination. Distribution of temperature, velocity on some typical section and the atrium space can be obtained; the result of numerical simulation can be visualized by post-processing module of FLUENT and TECPLOT software. The influence to the air flow distribution is simulated and calculated by the elements of different rates, angle, and height of the air supply flow. As for the specified case of the project, an optimized solution is obtained, that is supply air speed 6 m/s, angle 15°, air inlet height 7.5m, air temperature 291K.

The Effects of Pressure on Gas Turbine Combustor Performance: An Investigation via Numerical Simulation

2006 ◽  
Author(s):  
Yufeng Cui ◽  
Gang Xu ◽  
Bin Yu ◽  
Chaoqun Nie ◽  
Weiguang Huang
Keyword(s):  
Numerical Simulation ◽  
Gas Turbine ◽  
Radiation Heat Transfer ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Operating Pressure ◽  
Gas Turbine Combustor ◽  
Flamelet Model ◽  
Air Inlet ◽  
Operation Pressure

Performance tests of a gas turbine combustor are usually conducted at atmospheric or medium pressure which is quite different from its real operating condition. The effects of pressure on the performance of a gas turbine combustor for burning medium-heating-value syngas are researched by numerical simulation in this paper. The geometry of the combustor is modeled by coupling all its components including nozzle, combustor liner and sealant tube. In the simulation a laminar flamelet model and P-1 radiation model are adopted. The numerical results show that at the same fuel and air inlet temperature and the same equivalence ratio, the operation pressure has less effect on the flow fields, but its effect on the temperature distribution is obvious. Both the highest temperature in the combustor and the outlet temperature increase with increasing operating pressure because of the weakening of the dissociation of the H2O, CO2 and so on. Moreover, as pressure increases, the concentration of H2O and CO2 in the combustor increase, and so to does the absorption coefficient and the emissivity of gas inside the liner. As a result, the radiation heat transfer between the gas and the combustion liner wall is enhanced, and the wall temperature of the liner increases. The NOx emissions of the combustor are also distinctly higher at high pressure than at low pressure.

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