Numerical Simulation of Furnace Combustion Characteristic in HTAC

2011 ◽  
Vol 84-85 ◽  
pp. 274-278
Author(s):  
Tao Du ◽  
Li Sheng Ji ◽  
Guang Yi Gao
Keyword(s):  
Radiative Heat ◽  
Combustion Process ◽  
Concentration Field ◽  
Calorific Value ◽  
Combustion Characteristic ◽  
Combustion Model ◽  
Discrete Ordinates ◽  
Transfer Model ◽  
Field Temperature ◽  
Fluent Software

In this thesis, in the double preheating system of air and gas, the high temperature air combustion process of low calorific value gas, in which the FLUENT software is used as the calculating tool and furnace model as the object, is numerically simulated by use of the k-ε turbulent two-way model, the PDF combustion model, discrete-ordinates-method radiative heat transfer model and the modified NOX -generation thermal model. Get the flow field, temperature field and concentration field inside the furnace in different times.

scholarly journals Assessment of radiative heat transfer impact on a temperature distribution inside a real industrial swirled furnace

2020 ◽  
Vol 24 (6 Part A) ◽  
pp. 3663-3672
Author(s):  
Filip Juric ◽  
Milan Vujanovic ◽  
Marija Zivic ◽  
Mario Holik ◽  
Xuebin Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Temperature Distribution ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Combustion Process ◽  
Combustion Model ◽  
Discrete Ordinates ◽  
Participating Media ◽  
Combustion Systems

Combustion systems will continue to share a portion in energy sectors along the cur-rent energy transition, and therefore the attention is still given to the further improvements of their energy efficiency. Modern research and development processes of combustion systems are improbable without the usage of predictive numerical tools such as CFD. The radiative heat transfer in participating media is modelled in this work with discrete transfer radiative method (DTRM) and discrete ordinates method (DOM) by finite volume discretisation, in order to predict heat transfer inside combustion chamber accurately. The DTRM trace the rays in different directions from each face of the generated mesh. At the same time, DOM is described with the angle discretisation, where for each spatial angle the radiative transport equation needs to be solved. In combination with the steady combustion model in AVL FIRE? CFD code, both models are applied for computation of temperature distribution in a real oil-fired industrial furnace for which the experimental results are available. For calculation of the absorption coefficient in both models weighted sum of grey gasses model is used. The focus of this work is to estimate radiative heat transfer with DTRM and DOM models and to validate obtained results against experimental data and calculations without radiative heat transfer, where approximately 25% higher temperatures are achieved. The validation results showed good agreement with the experimental data with a better prediction of the DOM model in the temperature trend near the furnace outlet. Both radiation modelling approaches show capability for the computation of radiative heat transfer in participating media on a complex validation case of the combustion process in oil-fired furnace.

Parameter Based Combustion Model for Large Prechamber Gas Engines

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Jianguo Zhu ◽  
Andreas Wimmer ◽  
Eduard Schneßl ◽  
Hubert Winter ◽  
Franz Chmela
Keyword(s):  
Computing Time ◽  
Combustion Process ◽  
Combustion Model ◽  
Operating Parameters ◽  
Transfer Model ◽  
Boost Pressure ◽  
Considerable Difficulty ◽  
Single Cylinder ◽  
Simulation And Optimization ◽  
Short Computing Time

Challenging requirements for modern large engines regarding power output, fuel consumption, and emissions can only be achieved with carefully adapted combustion systems. With the improvement of simulation methods simulation work is playing a more and more important role for the engine development. Due to their simplicity and short computing time, one-dimensional and zero-dimensional calculation methods are widely applied for the engine cycle simulation and optimization. While the gas dynamic processes in the intake and exhaust systems can already be simulated with sufficient precision, it still represents a considerable difficulty to predict the combustion process exactly. In this contribution, an empirical combustion model for large prechamber gas engines is presented, which was evolved based on measurements on a single cylinder research engine using the design of experiment method. The combustion process in prechamber gas engines is investigated and reproduced successfully by means of a double-vibe function. The mathematical relationship between the engine operating parameters and the parameters of the double-vibe function was determined as a transfer model on the base of comprehensive measurements. The effects of engine operating parameters, e.g., boost pressure, charge temperature, ignition timing, and air/fuel ratio on the combustion process are taken into account in the transfer model. After adding modification functions, the model can be applied to gas engines operated with various gas fuels taking into account the actual air humidity. Comprehensive verifications were conducted on a single-cylinder engine as well as on full-scale engines. With the combination of the combustion model and a gas exchange simulation model the engine performance has been predicted satisfactorily. Due to the simple phenomenological structure of the model, a user-friendly model application and a short computing time is achieved.

scholarly journals Characteristics of Woody Cutting Waste Briquette with Paper Waste Pulp as Binder

2020 ◽  
Vol 190 ◽  
pp. 00030
Author(s):  
Qurrotin Ayunina Maulida Okta Arifianti ◽  
Azmi Alvian Gabriel ◽  
Syarif Hidayatulloh ◽  
Kuntum Khoiro Ummatin
Keyword(s):  
Moisture Content ◽  
Ignition Time ◽  
Combustion Process ◽  
Calorific Value ◽  
Volatile Matter ◽  
Proximate Analysis ◽  
Hydraulic Press ◽  
Combustion Characteristic ◽  
Paper Waste ◽  
Iron Mold

The current research aimed to increase the calorific value of woody cutting waste briquette with paper waste pulp as binder. There were three different binder variation used in this study, they are 5 %, 10 %, and 15 %. To create a briquette, a cylindrical iron mold with diameter of 3.5 cm and height of 3 cm and a hydraulic press with 2 t power were applied. The physical characteristics of the combination woody waste briquette and paper waste pulp, such as moisture content, ash content, volatile matter and carbon fix were examined using proximate analysis. The calorific value of briquetted fuel was tested by bomb calorimeter. The combustion test was performed to determine the combustion characteristic of briquettes, for example initial ignition time, temperature distribution, and combustion process duration. The general result shows that the calorific value of briquette stood in the range of 4 876 kCal kg–1 to 4 993 kCal kg–1. The maximum moisture content of briquette was 5.32 %. The longest burning time was 105 min.

Parameter Based Combustion Model for Large Pre-Chamber Gas Engines

2009 ◽  
Author(s):  
Jianguo Zhu ◽  
Andreas Wimmer ◽  
Eduard Schneßl ◽  
Hubert Winter ◽  
Franz Chmela
Keyword(s):  
Computing Time ◽  
Combustion Process ◽  
Combustion Model ◽  
Operating Parameters ◽  
Transfer Model ◽  
Boost Pressure ◽  
Single Cylinder ◽  
Simulation And Optimization ◽  
Short Computing Time ◽  
Chamber Gas

Challenging requirements for modern large engines regarding power output, fuel consumption and emissions can only be achieved with carefully adapted combustion systems. With the improvement of simulation methods simulation work is playing a more and more important role for the engine development. Due to their simplicity and short computing time, one-dimensional and zero-dimensional calculation methods are widely applied for the engine cycle simulation and optimization. While the gas dynamic processes in the intake and exhaust system can already be simulated with sufficient precision, it still represents a considerable difficulty to predict the combustion process exactly. In this contribution, an empirical combustion model for large pre-chamber gas engines is presented, which was evolved based on measurements on a single cylinder research engine using the DOE (Design of Experiments) method. The combustion process in pre-chamber gas engines is investigated and reproduced successfully by means of a Double-Vibe function. The mathematical relationship between the engine operating parameters and the parameters of the Double-Vibe function was determined as a transfer model on the base of comprehensive measurements. The effects of engine operating parameters e.g. boost pressure, charge temperature, ignition timing, air/fuel ratio on the combustion process are taken into account in the transfer model. After adding modification functions, the model can be applied to gas engines operated with various gas fuels taking into account the actual air humidity. Comprehensive verifications were conducted on a single cylinder engine as well as on full scale engines. With the combination of the combustion model and a gas exchange simulation model the engine performance has been predicted satisfactorily. Due to the simple phenomenological structure of the model, a user-friendly model application and a short computing time is achieved.

Sensitivity Analysis of a FGR Industrial Furnace for NOx Emission Using Frequency Domain Method

2005 ◽  
Vol 129 (2) ◽  
pp. 134-143 ◽  
Author(s):  
Qing Jiang ◽  
Chao Zhang ◽  
Jin Jiang
Keyword(s):  
Frequency Domain ◽  
Mixture Fraction ◽  
Combustion Process ◽  
Nox Emission ◽  
Moment Closure ◽  
Combustion Model ◽  
Frequency Domain Method ◽  
Transfer Model ◽  
Industrial Furnace ◽  
Nitric Oxides

Preliminary study has shown that the flue gas recirculation (FGR) is one of the effective ways to reduce the nitric oxides (NOx) emission in industrial furnaces. The sensitivity of the NOx emission from a FGR industrial furnace to the change in three major furnace input variables—inlet combustion air mass flow rate, inlet combustion air temperature, and pressure head of the FGR fan—is investigated numerically in this study. The investigation is carried out in frequency domain by superimposing sinusoidal signals of different frequencies on to the furnace control inputs around the design operating condition, and observing the frequency responses. The results obtained in this study can be used in the design of active combustion control systems to reduce NOx emission. The numerical simulation of the turbulent non-premixed combustion process in the furnace is conducted using a moment closure method with the assumed β probability density function for the mixture fraction. The combustion model is derived based on the assumption of instantaneous full chemical equilibrium. The discrete transfer radiation model is chosen as the radiation heat transfer model, and the weighted-sum-of-gray-gases model is used to calculate the absorption coefficient.

scholarly journals STUDI PERBANDINGAN SIMULASI PROSES PEMBAKARAN BATUBARA DAN VINASSE METODE NON-PREMIX COMBUSTION MODEL

Konversi ◽  
2015 ◽  
Vol 4 (1) ◽  
pp. 25
Author(s):  
Bayu Triwibowo ◽  
Abdul Halim ◽  
Annie Mufyda Rahmatika
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Combustion Process ◽  
Two Dimensions ◽  
Combustion Characteristic ◽  
Combustion Model ◽  
Premix Combustion ◽  
Computational Fluid Dynamics Cfd ◽  
Dynamics Method

Abstrak-Vinasse merupakan limbah dari industri gula dengan debit yang sangat besar sehingga harus diolah dengan berbagai metode. Salah satu alternatif metode yang dapat digunakan adalah pembakaran. Pembakaran merupakan reaksi kimia yang memproduksi panas dan dapat digunakan sebagai suplai energi untuk proses selanjutnya. Berdasarkan analisis proksimat dan ultimat, vinasse memiliki karakteristik yang hampir sama dengan batubara setelah mengalami proses evaporasi. Penelitian ini mempelajari perbandingan dari karakteristik pembakaran antara batubara dan vinasse sebagai bahan bakar yang dilihat dari aspek distribusi temperatur, distribusi spesies, dan vektor kecepatan. Proses pembakaran dijalankan dengan metode computational fluid dynamics (CFD) khususnya model pembakaran non-premix. Geometri dari ruang bakar yang digunakan adalah 84 x 5,2 m dengan kualitas ortogonal mesh yang digunakan mendekati 1 dan bentuk cell segiempat 100 persen. Simulasi pembakaran dijalankan dengan geometri 2D (dua dimensi) dengan udara sebagai oksidator. Hasil dari simulasi menunjukkan bahwa vinasse memiliki potensi untuk digunakan sebagai bahan bakar alternatif karena lebih cepat terbakar dibandingkan dengan batubara serta karakteristik lain yang sedikit berbeda. Kata kunci : pembakaran, vinasse, batubara, CFD, non-premix Abstract-Vinasse as a sugarcane waste has large amount of debit that must be treated through various methods. One of the methods is combustion. Combustion is a chemical reaction that produced heat which is can be used as energy supply for further process. Vinasse according to proxymate and ultimate analysis has characteristic similar to coal after being evaporated. This paper is studied about the comparassion of combustion characteristic between vinasse and coal as a fuel in terms of temperature distribution, species distribution, and velocity vector. Combustion process conducted with computational fluid dynamics method especially non-premix combustion model. The geometry of furnace is 84 m x 5.2 m with the orthogonal quality of mesh is close to 1 and 100 percent of quad cells. The simulation of combustion process conducted in 2D (two dimensions) with air as oxydizer. The results of the simulation shows that vinasse were very potential to use as a fuel with quicker combustion compared to coal but with slightly different characteristic. Keywords : Combustion, vinasse, coal, CFD, non-premix

A Sensitivity Study of NOx Emission to the Change in the Input Variables of a FGR Industrial Furnace

2003 ◽  
Author(s):  
Q. Jiang ◽  
C. Zhang ◽  
J. Jiang
Keyword(s):  
Dynamic Models ◽  
Mixture Fraction ◽  
Combustion Process ◽  
Sensitivity Study ◽  
Nox Emission ◽  
Moment Closure ◽  
Combustion Model ◽  
Transfer Model ◽  
Nitric Oxides ◽  
Input Variables

Preliminary study has shown that the flue gas recirculation (FGR) is one of the effective ways to reduce the Nitric Oxides (NOx) emission in industrial furnaces. The research reported in this paper concentrates mainly on the development of dynamic models suitable for on-line and real-time feedback control to reduce the NOx emission in industrial furnaces with FGR. To construct an appropriate dynamic model, the relationship between the NOx emission and the furnace input variables, such as the inlet combustion air mass flow rate, inlet combustion air temperature, and the pressure head of the FGR fan, has been investigated. A moment closure method with the assumed β probability density function (PDF) for the mixture fraction is used to model the turbulent non-premixed combustion process in the furnace. The combustion model is derived based on the assumption of instantaneous full chemical equilibrium. The discrete transfer radiation model is chosen as the radiation heat transfer model, and the weighted-sum-of-gray-gases model is used to calculate the absorption coefficient.

Combustion Performance and NO Emission in Industrial Furnace under Preheated Air Condition with Different Excess Air Ratio

2011 ◽  
Vol 402 ◽  
pp. 463-466
Author(s):  
Ya Xin Su ◽  
Wen Hui Wang
Keyword(s):  
Natural Gas ◽  
Beta Function ◽  
Combustion Process ◽  
Combustion Model ◽  
Discrete Ordinates ◽  
Industrial Furnace ◽  
No Emission ◽  
Gas Combustion ◽  
Combustion Performance ◽  
Excess Air

The effect of excess air ratio on combustion performance in an industrial furnace with a swirling burner was numerically modeled. The simulation was carried out at inlet oxygen fraction of 8% and a preheated air temperature of 1273 K for natural gas. The gas combustion process was calculated by a Beta function PDF (Probability Density Function) combustion model. The transportation of the turbulent flow in the furnace was modeled by Reynolds Stress Model (RSM). The radiation was simulated by a Discrete Ordinates method. The NO chemistry was simulated by thermal NO model. The effect of excess air ratio on NO emission, temperature, O2 and CO distribution in the furnace was investigated. Results showed that thermal NO emission increased from about 5 ppm to 70 ppm when the excess air ratio increased from 1.05 to 1.25. The burnout of natural gas was improved at increased excess air ratio, i.e., CO emission decreased. The maximum and average temperature in furnace did not change much at different excess air ratio. When the excess air ration is 1.1, both good burnout of fuel and low thermal NO emission (<15 ppm) were achieved.

Computation of Radiative Heat Transfer in a Cylindrical Enclosure

1996 ◽  
Author(s):  
Huiyu Fu ◽  
Ali Veshagh
Keyword(s):  
Heat Transfer ◽  
Absorption Coefficient ◽  
Combustion Chamber ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Gas Absorption ◽  
Combustion Model ◽  
Integration Scheme ◽  
Transfer Model ◽  
Zone Method

Abstract A radiative heat transfer model for cylindrical enclosure in which the gas and temperature are axi-symmetrically distributed was developed using the zone method of analysis. A rigorous numerical integration scheme was devised to calculate various types of direct exchange areas between different zones. The radiative heat transfer between gas zones and that between gas zones and surface zones could therefore be computed accurately based upon distributions of gas temperature and absorption coefficient. This radiation model was used to compute the radiative heat transfer in a diesel engine combustion chamber. Extensive soot data obtained via a sampling valve were used to calculate the gas absorption coefficient. An attempt was also made to allow for the radiation from the non-luminous gases, i.e. carbon dioxide and water vapour. Temperature distribution was obtained from a multi-zone combustion model. Results showed that the radiative heat transfer to the combustion chamber walls was negligible during the early stage of combustion, but represented a significant part of the total heat transfer when it reached its peak value. The results also showed the importance of radiative heat transfer between the various gas zones in the combustion chamber.

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