Numerical Study on High Temperature Air Combustion in U-Type Tube

2008 ◽  
Author(s):  
Xing Li ◽  
Li Jia ◽  
Tiantian Zhang ◽  
Lixin Yang
Keyword(s):  
High Temperature ◽  
Natural Gas ◽  
Combustion Chamber ◽  
Numerical Study ◽  
Maximum Temperature ◽  
No Emission ◽  
High Temperature Air Combustion ◽  
Average Temperature ◽  
Combustion Technology ◽  
Type Tube

In this paper, the combustion characteristics of natural gas with high-temperature air combustion technology in a U-type combustion chamber were investigated by the numerical method. The results of the CFD-based mathematical modeling of rated condition were compared with experimental data including the maximum temperature, average temperature and NO emission. The research indicates that the combustion can be well simulated using the suggested numerical model. The temperature distribution, velocity distribution in the combustion chamber and NO emission were attained. In addition, the effects of some parameters such as oxygen concentration, excessive air ratio and combustion air temperature were discussed in detail. It provided primarily theoretic basis for further study of natural gas high temperature air combustion.

Influence of Preheated Air Temperature on High Temperature Air Combustion in Furnace with Swirling Burner: a Modeling Study

2011 ◽  
Vol 354-355 ◽  
pp. 315-318
Author(s):  
Ya Xin Su ◽  
Wen Hui Wang
Keyword(s):  
High Temperature ◽  
Natural Gas ◽  
Air Temperature ◽  
Beta Function ◽  
Reynolds Stress Model ◽  
Combustion Model ◽  
Discrete Ordinates ◽  
No Emission ◽  
High Temperature Air Combustion ◽  
Gas Combustion

The high temperature air combustion performance of natural gas in an industrial furnace with a swirling burner was numerically modeled. A Beta function PDF (Probability Density Function) combustion model was selected to simulate the gas combustion combined with the Reynolds Stress Model (RSM) to simulate the turbulent flow. The radiation was simulated by a Discrete Ordinates method. The NO chemistry was simulated by thermal NO model. The simulation was performed at inlet air oxygen fraction 8% and the total air excess ratio 1.1 for natural gas. The effect of preheated air temperature on NO emission, temperature, O2 and CO distribution in the furnace was investigated. Results showed that thermal NO emission increased when the preheated air temperature increased from 1073 K to 1473K. When the preheated air temperature increased, both of the maximum and averaged temperature in the furnace increased. The oxygen was consumed by the formation of thermal NO at higher inlet air temperature and the fuel was not fully burnt out.

Numerical Study on NO Mechanism during High Temperature Air Combustion of Natural Gas

2012 ◽  
Vol 190-191 ◽  
pp. 609-614
Author(s):  
Ya Xin Su ◽  
Cui Wu Chen
Keyword(s):  
High Temperature ◽  
Natural Gas ◽  
No Reduction ◽  
Numerical Study ◽  
Combustion Process ◽  
Combustion Model ◽  
Small Contribution ◽  
High Temperature Air Combustion ◽  
Intermediate Model ◽  
No Formation

A full nitric oxide mechanism including thermal NO, prompt NO, N2O intermediate model and NO reduction model through reburning was used to calculate the NO formation during high temperature air combustion of natural gas in industrial furnace. The turbulent transportation was simulated by Reynolds stress model (RSM) and a modified Eddy-Break-Up (EBU) combustion model was applied to model the combustion process. A three-step reaction scheme of the natural gas combustion reaction was considered. Experimental data from published literature was adopted to validate the present models. Numerical results showed that thermal NO formation mechanism and reburning NO reduction mechanism were the dominant NO models. Reburning NO reduction could not be ignored. Prompt NO gave a small contribution to NO emission and the N2O intermediate model for NO formation was of little importance.

scholarly journals Mathematical modeling of a swirling jet in applications to low-emission combustion of low-grade fuels

2021 ◽  
Vol 23 (3) ◽  
pp. 308-317
Author(s):  
Usama J. Mizher ◽  
Peter A. Velmisov
Keyword(s):  
Carbon Dioxide ◽  
Natural Gas ◽  
Combustion Chamber ◽  
Negative Impact ◽  
Numerical Study ◽  
Combustion Process ◽  
Theoretical Data ◽  
Modern Society ◽  
Low Grade ◽  
Similar Solutions

Abstract. The search for new solutions in the field of energy, preventing negative impact on the environment, is one of the priority tasks for modern society. Natural gas occupies a stable position in the demand of the UES of Russia for fossil fuel. Biogas is a possible alternative fuel from organic waste. Biogas has an increased content of carbon dioxide, which affects the speed of flame propagation, and a lower content of methane, which reduces its heat of combustion. However, the combined combustion of natural gas and biogas, provided that the mixture of fuel and oxidizer is well mixed, can, on the one hand, reduce the maximum adiabatic temperature in the combustion chamber of power boilers at TPPs, and, on the other, increase the stability of biogas combustion. For the combined combustion of natural gas and biogas in operating power boilers, it is necessary to reconstruct the existing burners. For a high-quality reconstruction of burners capable of providing stable and low-toxic combustion of fuel, it is important to have theoretical data on the combustion effect of combustion of combinations of organic fuels on the temperature distribution in the combustion zone and on its maximum value. In this paper, self-similar solutions of the energy equation for axisymmetric motion of a liquid (gas) in a model of a viscous incompressible medium are obtained. Basing on them, a stationary temperature field in swirling jets is constructed. A set of programs based on the ANSYS Fluent software solver has been developed for modeling and researching of thermal and gas-dynamic processes in the combustion chamber. On the basis of the k - ϵ (realizable) turbulence model, the combustion process of a swirling fuel-air mixture is simulated. The results of an analytical and numerical study of the temperature and carbon dioxide distribution in the jet are presented.

Numerical study of steady natural convection in a liquefied natural gas cylindrical storage tank equipped with baffles

2019 ◽  
Vol 234 (5) ◽  
pp. 709-721 ◽  
Author(s):  
Mohamed Haddar ◽  
Moez Hammami ◽  
Mounir Baccar
Keyword(s):  
Rayleigh Number ◽  
Natural Gas ◽  
Lateral Surface ◽  
Storage Tank ◽  
Cooling System ◽  
Numerical Study ◽  
Gas Storage ◽  
Liquefied Natural Gas ◽  
Natural Gas Storage ◽  
Average Temperature

In this paper, a study of cooling system for a liquefied natural gas storage tank is conducted. Our objective is to remedy the heat ingress to the liquefied natural gas from the environment using baffles toward limiting temperature elevation in the tank, and then the Boil-off Gas (BOG) formation. A specific code based on the finite volume method is developed to supply a fine knowledge of the hydrodynamic and thermal liquefied natural gas characteristics in the cylindrical tank heated from bottom and lateral surfaces. The effect of the number, position and dimension of baffles, on the flow structure and thermal behavior, has been analyzed. According to our simulation results, the baffles should be placed at the top of tank nearby the lateral wall as the liquefied natural gas dimensionless average temperature can be reduced by 36%. The installation of four rectangular baffles, equally spaced around the perimeter of the tank, gives better homogenization of the temperature field and decreases the average temperature by about 44% in order to limit BOG formation. Finally, two correlations of the Nusselt number are established for the flat rectangular baffle plates and the lateral surface of the cylindrical liquefied natural gas storage tank as a function of the Rayleigh number, as well as the baffle number. Scaling of these correlations with the Rayleigh number gives exponents of 0.25 and 0.18 for lateral surface and baffle, respectively, which are in good agreement with literature.

206 Improvement Performance of Stoker-type Incinerator by Applying the High-temperature Air Combustion Technology

2014 ◽  
Vol 2014.24 (0) ◽  
pp. 62-65
Author(s):  
Tomohiro DENDA ◽  
Takashi NAKAYAMA ◽  
Norihito UETAKE ◽  
Eri WATANABE ◽  
Takao KITAGAWA
Keyword(s):  
High Temperature ◽  
High Temperature Air Combustion ◽  
Combustion Technology
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