scholarly journals Research on the Influence of Euro VI Diesel Engine Assembly Consistency on NOx Emissions

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5335
Author(s):  
Wei Yan ◽  
Tengyao Dou ◽  
Jinbo Wang ◽  
Na Mei ◽  
Guoxiang Li
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Combustion Chamber ◽  
Nox Emission ◽  
Combustion Model ◽  
Nox Emissions ◽  
Assembly Tolerance ◽  
Nozzle Extension ◽  
Assembly Tolerance Variation ◽  
Chamber Diameter

The assembly consistency of a diesel engine will affect its nitrogen oxides (NOx) emission variation. In order to improve the NOx emissions of diesel engines, a study was carried out based on the assembly tolerance variation of the diesel engine’s combustion system. Firstly, a diesel engine which meets the Euro VI standards together with the experimental data is obtained. The mesh model and combustion model of the engine combustion system are built in the Converge software (version 2.4, Tecplot, Bellevue, DC, USA), and the experimental data is used to calibrate the combustion model obtained in the Converge software. Then, the four-factor and three-level orthogonal simulation experiments are carried out on the dimension parameters that include nozzle extension height, throat diameter, shrinkage diameter and combustion chamber depth. Through mathematical analysis on the experimental data, the results show that the variation of nozzle extension height and combustion chamber depth have a strong influence on NOx emission results, and the variation of combustion chamber diameter also has a weak influence on NOx production. According to the regression model obtained from the analysis, there is a quadratic function relating the nozzle extension height and NOx emissions and the amount of NOx increases with increasing nozzle extension height. The relationship between emission performance and size parameters is complex. In the selected size range, the influence of the variation of the chamber diameter on NOx is linear. The variation of the chamber depth also has an effect on NOx production, and the simulation results vary with the change of assembly tolerance variation. Thus, in the engine assembly process, it is necessary to strictly control the nozzle extension height and combustion chamber depth. The research results are useful to improve the NOx emission of diesel engine and provide a basis for the control strategy of selective catalytic reduction (SCR) devices.

NOx Emissions From a Diesel Engine Fueled With Natural Gas

1995 ◽  
Vol 117 (4) ◽  
pp. 290-296 ◽  
Author(s):  
Y. Tao ◽  
K. B. Hodgins ◽  
P. G. Hill
Keyword(s):  
Diesel Engine ◽  
Natural Gas ◽  
Ignition Delay ◽  
Substantial Reduction ◽  
Equilibrium Concentration ◽  
Nox Emission ◽  
Combustion Model ◽  
Injection Timing ◽  
Exhaust Pipe ◽  
Nox Emissions

The performance and emission characteristics of a single-cylinder two-stroke diesel engine fueled with direct injection of natural gas entrained with pilot diesel ignition enhancer have been measured. The thermal efficiency of the optimum gas-diesel operation was shown to exceed that of the conventional diesel at full load, but to be less at part load where the ignition delay was excessive. At high load, where the NOx emission problem is most serious, substantial reduction in NOx emission rate was obtained with delay of injection timing and also with use of exhaust gas recirculation. Measured cylinder pressures were used with a three-zone combustion model to determine ignition delay and the temperatures of the burned gas. The predicted NOx emissions based on equilibrium concentration of NO at the maximum burned gas temperature were found to correlate closely with exhaust pipe measurements of NOx.

Design Analysis of a Micro Gas Turbine Combustion Chamber Burning Natural Gas

2012 ◽  
Author(s):  
André Perpignan V. de Campos ◽  
Fernando L. Sacomano Filho ◽  
Guenther C. Krieger Filho
Keyword(s):  
Experimental Data ◽  
Natural Gas ◽  
Combustion Chamber ◽  
Gas Turbines ◽  
Low Cost ◽  
Mixture Fraction ◽  
Combustion Model ◽  
Inlet Temperature ◽  
Gas Combustion ◽  
Micro Turbine

Gas turbines are reliable energy conversion systems since they are able to operate with variable fuels and independently from seasonal natural changes. Within that reality, micro gas turbines have been increasing the importance of its usage on the onsite generation. Comparatively, less research has been done, leaving more room for improvements in this class of gas turbines. Focusing on the study of a flexible micro turbine set, this work is part of the development of a low cost electric generation micro turbine, which is capable of burning natural gas, LPG and ethanol. It is composed of an originally automotive turbocompressor, a combustion chamber specifically designed for this application, as well as a single stage axial power turbine. The combustion chamber is a reversed flow type and has a swirl stabilized combustor. This paper is dedicated to the diagnosis of the natural gas combustion in this chamber using computational fluid dynamics techniques compared to measured experimental data of temperature inside the combustion chamber. The study emphasizes the near inner wall temperature, turbine inlet temperature and dilution holes effectiveness. The calculation was conducted with the Reynolds Stress turbulence model coupled with the conventional β-PDF equilibrium along with mixture fraction transport combustion model. Thermal radiation was also considered. Reasonable agreement between experimental data and computational simulations was achieved, providing confidence on the phenomena observed on the simulations, which enabled the design improvement suggestions and analysis included in this work.

Optimization of Engine Efficiency for Diesel Engine Equipped With EGR-VGT and Aftertreatment Systems

2019 ◽  
Author(s):  
Kuo Yang ◽  
Pingen Chen
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Diesel Engines ◽  
Intrinsic Property ◽  
Nox Emission ◽  
Nox Emissions ◽  
Minimum Phase ◽  
Engine Efficiency ◽  
Simulation Results ◽  
Aftertreatment Systems

Abstract Engine efficiency improvement is very critical for medium to heavy-duty vehicles to reduce Diesel fuel consumption and enhance U.S. energy security. The tradeoff between engine efficiency and NOx emissions is an intrinsic property that prevents modern Diesel engines, which are generally equipped with exhaust gas recirculation (EGR) and variable geometry turbocharger (VGT), from achieving the optimal engine efficiency while meeting the stringent NOx emission standards. The addition of urea-based selective catalytic reduction (SCR) systems to modern Diesel engine aftertreatment systems alleviate the burden of NOx emission control on Diesel engines, which in return creates extra freedom for optimizing Diesel engine efficiency. This paper proposes two model-based approaches to locate the optimal operating point of EGR and VGT in the air-path loop to maximize the indicated efficiency of turbocharged diesel engine. Simulation results demonstrated that the engine brake specific fuel consumption (BSFC) can be reduced by up to 1.6% through optimization of EGR and VGT, compared to a baseline EGR-VGT control which considers both NOx emissions and engine efficiency on engine side. The overall equivalent BSFCs are 1.8% higher with optimized EGR and VGT control than with the baseline control. In addition, the influence of reducing EGR valve opening on the non-minimum phase behavior of the air path loop is also analyzed. Simulation results showed slightly stronger non-minimum phase behaviors when EGR is fully closed.

scholarly journals Computational and experimental determination of flame radiation parameters in the combustion chamber of a marine diesel engine

2020 ◽  
pp. 98-102
Author(s):  
Б.И. Руднев ◽  
О.В. Повалихина
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Combustion Chamber ◽  
Experimental Method ◽  
Diesel Engines ◽  
Flame Temperature ◽  
Marine Diesel Engine ◽  
Gas Temperature ◽  
Flame Radiation ◽  
Marine Diesel

Температура пламени и степень черноты определяют его собственное излучение. Однако оценка указанных параметров на стадии проектирования судовых дизелей представляет собой трудную и еще пока нерешенную проблему. Последнее обусловливается сложностью достоверного математического моделирования процесса сгорания топлива в дизельных двигателях и весьма высокой стоимостью экспериментальных исследований в этой области. Целью данной статьи является разработка расчетно-экспериментального метода определения параметров излучения пламени в камере сгорания судового дизеля 6 ЧН 24/36. Показано, что оценка величины температуры пламени в камере сгорания в функции угла поворота коленчатого вала может быть выполнена по температуре газов, найденной из экспериментальной или расчетной индикаторной диаграммы и специального параметра. Последний определяется на основании зависимости, полученной путем обобщения экспериментальных данных по измерениям температуры пламени на ряде дизельных двигателей. Представлены результаты по температуре пламени для судового дизеля 6 ЧН 24/36, полученные с использованием разработанного расчетно-экспериментального метода. Установлено, что с ростом нагрузки температура пламени возрастает. При этом в диапазоне изменения нагрузки дизеля от 50% до 100% от номинальной мощности увеличение температуры пламени примерно в два раза превышает увеличение температуры газов. Использование полученных результатов для оценки собственных потоков излучения пламени в камере сгорания судового дизеля 6 ЧН 24/36 и сопоставление их с известными экспериментальными данными показало сходимость в пределах 10 – 15%. The flame temperature and radiating power are determined with its own radiation. However, the assessment of these parameters at the design stage of marine diesel engines is a complicated and still unsolved problem. The latter is due to the complexity of reliable mathematical modeling of the fuel combustion process in diesel engines and the very high cost of experimental research in this area. The purpose of this article is to develop a computational and experimental method for determining the parameters of flame radiation in the combustion chamber of marine diesel engine 6 ChN 24/36. It is shown that the estimation of the value of flame temperature in the combustion chamber as a function of the crankshaft rotation angle can be performed using the gas temperature found from the experimental or calculated indicator diagram and a special parameter. The latter is determined on the basis of the dependence obtained by generalizing experimental data of the flame temperature measurements at a number of diesel engines. The results on the flame temperature for marine diesel engine 6 ChN 24/36, obtained using the developed computational and experimental method, are presented. It has been found that the flame temperature increases with increasing load. At the same time, in the range of diesel load variation from 50% to 100% of the nominal power, an increase in the flame temperature is approximately twice more than an increase in the gas temperature. The use of the results obtained to assess the intrinsic fluxes of flame radiation in the combustion chamber of marine diesel engine 6 ChN 24/36 and their comparison with the known experimental data showed the convergence within 10 - 15%.

Numerical Investigation of NOx Emissions Characteristics of a Natural Gas Premixed Burner Based on Chemical Reactor Network Model

2019 ◽  
Author(s):  
Bin Mu ◽  
Fulin Lei ◽  
Weiwei Shao ◽  
Xunwei Liu ◽  
Zhedian Zhang ◽  
...  
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Chemical Reactor ◽  
Nox Emission ◽  
Recirculation Region ◽  
Nox Emissions ◽  
Nox Formation ◽  
Chemical Reactor Network ◽  
Thermal Nox ◽  
Reactor Network

Abstract Numerical optimization of nitrogen oxides (NOx) formation is an essential factor during developing low pollution combustor of gas turbine. The Computational Fluid Dynamics-Chemical Reactor Network (CFD-CRN) hybrid method has a great advantage in fast and accurate prediction of combustor NOx emissions. In this work, a hybrid CFD-CRN approach is established to predict pollutant emissions of a lean premixed model burner for gas turbine applications. Several criteria are compared for separating the combustor into chemically and physically homogeneous zones, and the crucial parameters such as residence time and flue gas recirculation ratio are calculated. The CRN model is preliminarily verified with experimental data. The effects of pressure and fuel-air unmixedness on NOx formation are subsequently investigated. In addition, the effects of changes in fuel/air flow distribution and crucial parameters of CRN model on NOx emissions are also estimated under different pressures and fuel-air unmixedness. The combustor is divided into several zones including reaction preheating region, flame front region, flame transition region, post flame region, main recirculation region and corner recirculation region based on CFD results of fuel-air mixing characteristics, velocity field, temperature field, distribution of OH mass fraction and Damkohler number. The complex CRN model has the advantage of predicting NOx emission characteristics under higher Tad conditions compared with the simple model, and its prediction of NOx emission shows good agreement with experimental data under various equivalence ratio conditions. The structure and distribution of several regions of CRN model are analogous but not significant when Reynolds number exceeds 105 under high pressure. The pathway analysis shows that the NOx emission gradually decreases through N2O and NNH mechanisms, resulted from the decreasing concentration of O radical under low Tad and high pressure. However, the pressure could significantly promote thermal NOx formation resulting form increase of temperature. The fuel-air unmixedness results in the increase of maximum flame temperature, which has significant effect on change of the CRN regions-separating. The fuel-air unmixedness causes the significant increasing of thermal NOx formation.

A Study on Biodiesel NOx Emission Control With the Reduced Chemical Kinetics Model

2014 ◽  
Vol 136 (10) ◽  
Author(s):  
Juncheng Li ◽  
Zhiyu Han ◽  
Cai Shen ◽  
Chia-fon Lee
Keyword(s):  
Chemical Kinetics ◽  
Combustion Process ◽  
Operating Conditions ◽  
Nox Emission ◽  
Kinetics Model ◽  
Combustion Model ◽  
Nox Emissions ◽  
Soot Emission ◽  
Start Of Injection ◽  
Combustion Processes

In this paper, the effects of the start of injection (SOI) timing and exhaust gas recirculation (EGR) rate on the nitrogen oxides (NOx) emissions of a biodiesel-powered diesel engine are studied with computational fluid dynamics (CFD) coupling with a chemical kinetics model. The KIVA code coupling with a CHEMKIN-II chemistry solver is applied to the simulation of the in-cylinder combustion process. A surrogate biodiesel mechanism consisting of two fuel components is employed as the combustion model of soybean biodiesel. The in-cylinder combustion processes of the cases with four injection timings and three EGR rates are simulated. The simulation results show that the calculated NOx emissions of the cases with default EGR rate are reduced by 20.3% and 32.9% when the injection timings are delayed by 2- and 4-deg crank angle, respectively. The calculated NOx emissions of the cases with 24.0% and 28.0% EGR are reduced by 38.4% and 62.8%, respectively, compared to that of the case with default SOI and 19.2% EGR. But higher EGR rate deteriorates the soot emission. When EGR rate is 28.0% and SOI is advanced by 2 deg, the NOx emission is reduced by 55.1% and soot emission is controlled as that of the case with 24% EGR and default SOI. The NOx emissions of biodiesel combustion can be effectively improved by SOI retardation or increasing EGR rate. Under the studied engine operating conditions, introducing more 4.8% EGR into the intake air with unchanged SOI is more effective for NOx emission controlling than that of 4-deg SOI retardation with default EGR rate.

Investigation of Numerical Simulation in Combustion Chamber Predictability

2011 ◽  
Vol 317-319 ◽  
pp. 2085-2090
Author(s):  
Rang Shu Xu ◽  
Ling Niu ◽  
Xin Zhu Weng ◽  
Long Xu ◽  
Min Li Bai
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Combustion Chamber ◽  
Domain Boundary ◽  
Combustion Model ◽  
Physical Parameters ◽  
Computational Domain ◽  
Flame Tube ◽  
Vof Model ◽  
Adopted Model

For the purpose of increasing applicability of combustion chamber simulation, computational domain, boundary condition, simplicity of complicated structures, mesh generation and physical parameters are investigated in this paper. An annular combustion chamber of some aero-engine is studied by means of predictive numerical simulation. The computational domain includes diffuser, swirler, inner flame tube, inner ring of combustion chamber and the flow channel of all the holes on the wall of flame tube. The film cooling holes row was simplified into a slit filled with porous media. Realizable k-turbulent model and non-premixed combustion model were adopted. Model of pressure atomization nozzle were calibrated and validated through inner nozzle flow property two-phase flow VOF model and experimental data. Physical parameters are express through polynomial functions. A commercial CFD code was adopted on a high performance computing cluster with parallel algorithm and the solving method are high-order discretization scheme. The velocity, pressure, temperature, fuel spray, density of fuel and productions, etc. are calculated and validated with the experimental data.

A Study on Biodiesel NOx Emission Control With the Reduced Chemical Kinetics Model

2013 ◽  
Author(s):  
Juncheng Li ◽  
Chia-fon F. Lee ◽  
Zhiyu Han ◽  
Cai Shen ◽  
Mianzhi Wang
Keyword(s):  
Chemical Kinetics ◽  
Nox Emission ◽  
Kinetics Model ◽  
Combustion Model ◽  
Nox Emissions ◽  
Soot Emission ◽  
Start Of Injection ◽  
Soybean Biodiesel ◽  
Combustion Processes ◽  
Gas Recirculation

In this paper, the effects of the start of injection (SOI) timing and EGR rate on the nitrogen oxide (NOx) emissions of biodiesel-powered diesel engine are studied with computational fluid dynamics (CFD) coupling with a chemical kinetics model. A surrogate biodiesel mechanism consisting of two fuel components is employed as the combustion model of soybean biodiesel. The in-cylinder combustion processes of the cases with four injection timings and three exhaust gas recirculation (EGR) rates are simulated. The simulation results show that the NOx emissions of biodiesel combustion can be effectively improved by SOI retardation or increasing EGR rate. The calculated NOx emissions of the cases with default EGR rate are reduced by 20.3% and 32.9% when the injection timings are delayed by 2-degree and 4-degree crank angle, respectively. The calculated NOx emissions of the cases with 24.0% and 28.0% EGR are reduced by 38.4% and 62.8%, respectively, compared to that of the case with default SOI and 19.2% EGR. But higher EGR rate deteriorates the soot emission. When EGR rate is 28.0% and SOI is advanced by 2-degree, the NOx emission is reduced by 55.1% and soot emission is controlled as that of the case with 24% EGR and default SOI.

Improving the NOx-BSFC Trade Off of a Turbocharged Large Diesel Engine Using Performance Simulation

2002 ◽  
Author(s):  
Ki-Doo Kim ◽  
Dong-Hun Kim
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Fuel Consumption ◽  
Fuel Injection ◽  
Nox Emission ◽  
Injection System ◽  
Miller Cycle ◽  
Intake Valve ◽  
Closing Time ◽  
Performance Simulation

The purpose of this study is to determine the optimum intake valve closing time of a large diesel engine having lower fuel consumption and lower NOx emission. The performance simulation has been conducted for this purpose, and a phenomenological combustion model is verified by experimental data of heat release rate and NOx emission in order to enhance the prediction quality of the performance simulation. The results of performance simulation are compared with measured data to confirm the modeling method and results. The fuel injection system simulation has been also performed to get fuel injection rate, and the results is also verified by experimental data of fuel injection pump pressure and injected fuel mass. The performance simulation investigate the application of Miller cycle to a large diesel engine, and so, the intake valve closing time is determined at the condition of reducing NOx emission and fuel consumption at the same time. As that result, Miller cycle has a feature that the maximum reduction of NOx emission is 15.7% while the improvement of specific fuel oil consumption is 1.7g/kWh.

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