scholarly journals Implementation and Parameter Analysis of the Knock Phenomenon of a Marine Dual-Fuel Engine Based on a Two-Zone Combustion Model

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 602
Author(s):  
Fang-Kun Zou ◽  
Hong Zeng ◽  
Huai-Yu Wang ◽  
Xin-Xin Wang ◽  
Zhao-Xin Xu
Keyword(s):  
Natural Gas ◽  
Air Temperature ◽  
Compression Ratio ◽  
Operating Parameter ◽  
Parameter Analysis ◽  
Combustion Model ◽  
Dual Fuel ◽  
Inlet Temperature ◽  
Dimensional Model ◽  
Engine Knock

The stable working window of a dual-fuel engine is narrow, and it is prone to knock during operation. The occurrence of knock limits the load and torque output of a dual-fuel engine, and even causes engine damage in severe cases. The existing volumetric model of marine dual-fuel engine has little research on the related problems of knock simulation. In order to analyze the causes of knock phenomenon and the influence of operating parameter changes on knock, under the Matlab/Simulink simulation environment, a quasi-dimensional model was established with MAN 8L51/60DF dual-fuel engine as the prototype, and the model was calibrated using the bench data. The knock intensity index coefficient (KI) was used as the evaluation index of knock intensity. Three parameters, the intake air temperature, compression ratio, and natural gas intake, were selected as variables to simulate the engine. According to the analysis of the simulation results, the influence of the parameter changes on the occurrence of engine knock phenomenon and knock intensity could be further studied. The results showed that the combination of the KI model and the quasi-dimensional model could effectively and accurately predict the engine performance and knock trend. The change of gas inlet quality, compression ratio, and inlet temperature could promote the occurrence of detonation, the engine knock could be avoided by controlling the intake air temperature below 336 K, compression ratio not exceeding 15 or the intake volume of natural gas per cycle not exceeding 11.25 g/cycle.

scholarly journals Parametric Knocking Performance Investigation of Spark Ignition Natural Gas Engines and Dual Fuel Engines

2020 ◽  
Vol 8 (6) ◽  
pp. 459 ◽  
Author(s):  
La Xiang ◽  
Gerasimos Theotokatos ◽  
Haining Cui ◽  
Keda Xu ◽  
Hongkai Ben ◽  
...  
Keyword(s):  
Natural Gas ◽  
Compression Ratio ◽  
Engine Performance ◽  
Spark Ignition ◽  
Combustion Model ◽  
Dual Fuel ◽  
Ignition Timing ◽  
Natural Gas Engines ◽  
Study Results ◽  
Pilot Fuel

Both spark ignition (SI) natural gas engines and compression ignition (CI) dual fuel (DF) engines suffer from knocking when the unburnt mixture ignites spontaneously prior to the flame front arrival. In this study, a parametric investigation is performed on the knocking performance of these two engine types by using the GT-Power software. An SI natural gas engine and a DF engine are modelled by employing a two-zone zero-dimensional combustion model, which uses Wiebe function to determine the combustion rate and provides adequate prediction of the unburnt zone temperature, which is crucial for the knocking prediction. The developed models are validated against experimentally measured parameters and are subsequently used for performing parametric investigations. The derived results are analysed to quantify the effect of the compression ratio, air-fuel equivalence ratio and ignition timing on both engines as well as the effect of pilot fuel energy proportion on the DF engine. The results demonstrate that the compression ratio of the investigated SI and DF engines must be limited to 11 and 16.5, respectively, for avoiding knocking occurrence. The ignition timing for the SI and the DF engines must be controlled after −38°CA and 3°CA, respectively. A higher pilot fuel energy proportion between 5% and 15% results in increasing the knocking tendency and intensity for the DF Engine at high loads. This study results in better insights on the impacts of the investigated engine design and operating settings for natural gas (NG)-fuelled engines, thus it can provide useful support for obtaining the optimal settings targeting a desired combustion behaviour and engine performance while attenuating the knocking tendency.

A Refined Analytical Combustion Model for Evaluating the Effects of EGR Percentage on Improvement of Knock Characteristics of Natural Gas in Spark Ignition Engine

2008 ◽  
Author(s):  
Mohammad Ghanbari ◽  
Hesameddin Safari ◽  
Seyed Ali Jazayeri ◽  
Reza Ebrahimi
Keyword(s):  
Natural Gas ◽  
Compression Ratio ◽  
Thermal Efficiency ◽  
Combustion Products ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Combustion Model ◽  
Lean Burn ◽  
Spark Timing ◽  
Engine Knock

Accurate modeling of engine knock onset is needed for control of SI engine combustion and increase of thermal efficiency. This contribution presents a refined model for analysis of engine knock when using natural gas fuel and EGR. The model is used to compare the effectiveness of EGR to other knock suppression methods such as lean-burn combustion, compression ratio reduction, and ignition timing retardation. The model consists of two zones: a burned combustion products region and an unburned reactants comprising the end gas region, separated by a flame front of negligible thickness. A mass burning rate is derived from a turbulent combustion model. FORTRAN code as programming software is used for combustion simulation. Operating conditions which affect an engine’s tendency to knock are discussed. The model was validated by comparison to experimental data. Results show that EGR addition is more effective at suppressing knock, while maintaining high thermal efficiency and output work, compared to other knock suppression techniques such as inlet pressure and temperature, equivalence ratio, spark timing, or compression ratio.

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.

Performance and Emissions Characteristics of Bio-Diesel (B100)-Ignited Methane and Propane Combustion in a Four Cylinder Turbocharged Compression Ignition Engine

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
N. T. Shoemaker ◽  
C. M. Gibson ◽  
A. C. Polk ◽  
S. R. Krishnan ◽  
K. K. Srinivasan
Keyword(s):  
Natural Gas ◽  
Fuel Efficiency ◽  
Dual Fuel ◽  
Compression Ignition ◽  
Propane Combustion ◽  
Compression Ignition Engine ◽  
Engine Knock ◽  
Performance And Emissions ◽  
Cylinder Compression ◽  
Dual Fueling

Different combustion strategies and fuel sources are needed to deal with increasing fuel efficiency demands and emission restrictions. One possible strategy is dual fueling using readily available resources. Propane and natural gas are readily available with the current infrastructure and biodiesel is growing in popularity as a renewable fuel. This paper presents experimental results from dual fuel combustion of methane (as a surrogate for natural gas) and propane as primary fuels with biodiesel pilots in a 1.9 liter, turbocharged, 4-cylinder compression ignition engine at 1800 rev/min. Experiments were performed with different percentage energy substitutions (PES) of propane and methane and at different brake mean effective pressures (BMEP/bmep). Brake thermal efficiency (BTE) and emissions (NOx, HC, CO, CO2, O2 and smoke) were also measured. Maximum PES levels for B100-methane dual fueling were limited to 70% at 2.5 bars bmep and 48% at 10 bars bmep, and corresponding values for B100-propane dual fueling were 64% and 43%, respectively. Maximum PES was limited by misfire at 2.5 bars bmep and the onset of engine knock at 10 bars bmep. Dual fuel BTEs approached straight B100 values at 10 bars bmep while they were significantly lower than B100 values at 2.5 bars bmep. In general, dual fueling was beneficial in reducing NOx and smoke emissions by 33% and 50%, respectively, from baseline B100 levels; however, both CO and THC emissions were significantly higher than baseline B100 levels at all PES and loads.

Cylinder Specific Pressure Predictions for Advanced Dual Fuel Compression Ignition Engines Utilizing a Two-Stage Functional Data Analysis

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Xiao Huang ◽  
Lulu Kang ◽  
Mateos Kassa ◽  
Carrie Hall
Keyword(s):  
Combustion Process ◽  
Operating Parameter ◽  
Combustion Model ◽  
Dual Fuel ◽  
Compression Ignition ◽  
Cylinder Pressure ◽  
Specific Pressure ◽  
Compression Ignition Engine ◽  
Two Stage ◽  
Pressure Trace

In-cylinder pressure is a critical metric that is used to characterize the combustion process of engines. While this variable is measured on many laboratory test beds, in-cylinder pressure transducers are not common on production engines. As such, accurate methods of predicting the cylinder pressure have been developed both for modeling and control efforts. This work examines a cylinder-specific pressure model for a dual fuel compression ignition engine. This model links the key engine input variables to the critical engine outputs including indicated mean effective pressure (IMEP) and peak pressure. To identify the specific impact of each operating parameter on the pressure trace, a surrogate model was produced based on a functional Gaussian process (GP) regression approach. The pressure trace is modeled as a function of the operating parameters, and a two-stage estimation procedure is introduced to overcome various computational challenges. This modeling method is compared to a commercial dual fuel combustion model and shown to be more accurate and less computationally intensive.

Performance and Emissions Characteristics of Bio-Diesel (B100)-Ignited Methane and Propane Combustion in a Four Cylinder Turbocharged Compression Ignition Engine

2011 ◽  
Author(s):  
N. T. Shoemaker ◽  
C. M. Gibson ◽  
A. C. Polk ◽  
S. R. Krishnan ◽  
K. K. Srinivasan
Keyword(s):  
Natural Gas ◽  
Fuel Efficiency ◽  
Dual Fuel ◽  
Propane Combustion ◽  
Compression Ignition Engine ◽  
Brake Thermal Efficiency ◽  
Engine Knock ◽  
Performance And Emissions ◽  
Dual Fuel Combustion ◽  
Dual Fueling

Different combustion strategies and fuel sources are needed to deal with increasing fuel efficiency demands and emission restrictions. One possible strategy is dual fueling using readily available resources. Propane and natural gas are readily available with the current infrastructure and biodiesel is growing in popularity as a renewable fuel. This paper presents experimental results from dual fuel combustion of methane (as a surrogate for natural gas) and propane as primary fuels with biodiesel pilots in a 1.9 liter, turbocharged, 4 cylinder diesel engine at 1800 rev/min. Experiments were performed with different percentage energy substitutions (PES) of propane and methane and at different brake mean effective pressures (BMEP/bmep). Brake thermal efficiency (BTE) and emissions (NOx, HC, CO, CO2, O2 and smoke) were also measured. Maximum PES levels for B100-methane dual fuelling were limited to 70% at 2.5 bar bmep and 48% at 10 bar bmep, and corresponding values for B100-propane dual fuelling were 64% and 43%, respectively. Maximum PES was limited by misfire at 2.5 bar bmep and the onset of engine knock at 10 bar bmep. Dual fuel BTEs approached straight B100 values at 10 bar bmep while they were significantly lower than B100 values at 2.5 bar bmep. In general dual fuelling was beneficial in reducing NOx and smoke emissions by 33% and 50%, respectively from baseline B100 levels; however, both CO and THC emissions were significantly higher than baseline B100 levels at all PES and loads.

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