scholarly journals Development of a method to improve the calculation accuracy of specific fuel consumption for performance modeling of air-breathing engines

2021 ◽  
Vol 2 (8 (110)) ◽  
pp. 23-30
Author(s):  
Oleh Kislov ◽  
Maya Ambrozhevich ◽  
Mykhailo Shevchenko
Keyword(s):  
Heat Capacity ◽  
Fuel Consumption ◽  
Estimation Error ◽  
Engine Performance ◽  
Isobaric Heat Capacity ◽  
Specific Fuel Consumption ◽  
Calculation Error ◽  
Turbofan Engine ◽  
Air Breathing

Determination of specific fuel consumption of air-breathing engines is one of the problems of modeling their performance. As a rule, the estimation error of the specific fuel consumption while calculating air-breathing engine performance is greater than that of thrust. In this work, this is substantiated by the estimation error of the fuel-air ratio, which weakly affects thrust but significantly affects the specific fuel consumption. The presence of a significant error in the fuel-air ratio is explained by the use of simplified methods, which use the dependence of enthalpy as a function of mixture temperature and composition without taking into account the effect of pressure. The developed method to improve the calculation accuracy of specific fuel consumption of air-breathing engines is based on the correction of the fuel-air ratio in the combustor, determined by the existing mathematical models. The correction of the fuel-air ratio is made using the dependences of enthalpy on mixture temperature, pressure and composition. The enthalpy of the mixture is calculated through the average isobaric heat capacity obtained by integrating the isobaric heat capacity, depending on mixture temperature, pressure and composition. The calculation accuracy of the fuel-air ratio was verified by comparing it with the known experimental data on the combustion chamber of the General Electric CF6-80A engine (USA). The average calculation error of the fuel-air ratio does not exceed 3 %. The developed method was applied for correcting the specific fuel consumption for calculating the altitude-airspeed performance of the D436-148B turbofan engine (Ukraine), which made it possible to reduce the estimation error of the fuel-air ratio and specific fuel consumption to an average of 3 %

Two-Stroke Marine Diesel Engine Variable Injection Timing System Performance Evaluation and Optimum Setting for Minimum Fuel Consumption at Acceptable NOx Levels

2014 ◽  
Author(s):  
Dimitrios T. Hountalas ◽  
Spiridon Raptotasios ◽  
Antonis Antonopoulos ◽  
Stavros Daniolos ◽  
Iosif Dolaptzis ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Engine Performance ◽  
Operating Conditions ◽  
Specific Fuel Consumption ◽  
Injection Timing ◽  
Nox Emissions ◽  
Pressure Measurements ◽  
Cylinder Pressure ◽  
Start Of Injection

Currently the most promising solution for marine propulsion is the two-stroke low-speed diesel engine. Start of Injection (SOI) is of significant importance for these engines due to its effect on firing pressure and specific fuel consumption. Therefore these engines are usually equipped with Variable Injection Timing (VIT) systems for variation of SOI with load. Proper operation of these systems is essential for both safe engine operation and performance since they are also used to control peak firing pressure. However, it is rather difficult to evaluate the operation of VIT system and determine the required rack settings for a specific SOI angle without using experimental techniques, which are extremely expensive and time consuming. For this reason in the present work it is examined the use of on-board monitoring and diagnosis techniques to overcome this difficulty. The application is conducted on a commercial vessel equipped with a two-stroke engine from which cylinder pressure measurements were acquired. From the processing of measurements acquired at various operating conditions it is determined the relation between VIT rack position and start of injection angle. This is used to evaluate the VIT system condition and determine the required settings to achieve the desired SOI angle. After VIT system tuning, new measurements were acquired from the processing of which results were derived for various operating parameters, i.e. brake power, specific fuel consumption, heat release rate, start of combustion etc. From the comparative evaluation of results before and after VIT adjustment it is revealed an improvement of specific fuel consumption while firing pressure remains within limits. It is thus revealed that the proposed method has the potential to overcome the disadvantages of purely experimental trial and error methods and that its use can result to fuel saving with minimum effort and time. To evaluate the corresponding effect on NOx emissions, as required by Marpol Annex-VI regulation a theoretical investigation is conducted using a multi-zone combustion model. Shop-test and NOx-file data are used to evaluate its ability to predict engine performance and NOx emissions before conducting the investigation. Moreover, the results derived from the on-board cylinder pressure measurements, after VIT system tuning, are used to evaluate the model’s ability to predict the effect of SOI variation on engine performance. Then the simulation model is applied to estimate the impact of SOI advance on NOx emissions. As revealed NOx emissions remain within limits despite the SOI variation (increase).

Characteristics of Water-in-Diesel Emulsions in a Single Cylinder Compression Ignition Engine

2014 ◽  
Author(s):  
Teja Gonguntla ◽  
Robert Raine ◽  
Leigh Ramsey ◽  
Thomas Houlihan
Keyword(s):  
Fuel Consumption ◽  
Direct Injection ◽  
Engine Performance ◽  
Operating Conditions ◽  
Specific Fuel Consumption ◽  
Brake Specific Fuel Consumption ◽  
Compression Ignition Engine ◽  
Oil Emulsion ◽  
Single Cylinder ◽  
Performance And Emission

The objective of this project was to develop both engine performance and emission profiles for two test fuels — a 6% water-in-diesel oil emulsion (DOE-6) fuel and a neat diesel (D100) fuel. The testing was performed on a single cylinder, direct-injection, water-cooled diesel engine coupled to an eddy current dynamometer. Output parameters of the engine were used to calculate Brake Specific Fuel Consumption (BSFC) and Engine Efficiency (η) for each test fuel. DOE-6 fuels generated a 24% reduction in NOX and a 42% reduction in Carbon Monoxide emissions over the tested operating conditions. DOE-6 fuels presented higher ignition delays — between 1°-4°, yielded 1%–12% lower peak cylinder pressures and produced up to 5.5% lower exhaust temperatures. Brake Specific Fuel consumption increased by 6.6% for the DOE-6 fuels as compared to the D100 fuels. This project is the first research done by a New Zealand academic institution on water-in-diesel emulsion fuels.

Optimization of Turbofan Propulsion Cycle Using a Genetic Algorithm

2010 ◽  
Author(s):  
Adel Ghenaiet
Keyword(s):  
Genetic Algorithm ◽  
Fuel Consumption ◽  
Pressure Ratio ◽  
Engine Performance ◽  
Optimization Procedure ◽  
Specific Fuel Consumption ◽  
High Mass ◽  
Design Parameters ◽  
Inlet Temperature ◽  
Simplifying Assumptions

This paper presents an evolutionary approach as the optimization framework to design for the optimal performance of a high-bypass unmixed turbofan to match with the power requirements of a commercial aircraft. The parametric analysis had the objective to highlight the effects of the principal design parameters on the propulsive performance in terms of specific fuel consumption and specific thrust. The design optimization procedure based on the genetic algorithm PIKAIA coupled to the developed engine performance analyzer (on-design and off-design) aimed at finding the propulsion cycle parameters minimizing the specific fuel consumption, while meeting the required thrusts in cruise and takeoff and the restrictions of temperatures limits, engine size and weight as well as pollutants emissions. This methodology does not use engine components’ maps and operates on simplifying assumptions which are satisfying the conceptual or early design stages. The predefined requirements and design constraints have resulted in an engine with high mass flow rate, bypass ratio and overall pressure ratio and a moderate turbine inlet temperature. In general, the optimized engine is fairly comparable with available engines of equivalent power range.

scholarly journals Control of Exhaust Emissions Using Piston Coating on Two-StrokeSI Engines with Gasoline Blends

2021 ◽  
Vol 8 (1) ◽  
pp. H16-H20
Author(s):  
A.V.N.S. Kiran ◽  
B. Ramanjaneyulu ◽  
M. Lokanath M. ◽  
S. Nagendra ◽  
G.E. Balachander
Keyword(s):  
Fuel Consumption ◽  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
Fossil Fuels ◽  
Engine Performance ◽  
Exhaust Emissions ◽  
Specific Fuel Consumption ◽  
Thermal Barrier ◽  
Piston Crown ◽  
Barrier Coating

An increase in fuel utilization to internal combustion engines, variation in gasoline price, reduction of the fossil fuels and natural resources, needs less carbon content in fuel to find an alternative fuel. This paper presents a comparative study of various gasoline blends in a single-cylinder two-stroke SI engine. The present experimental investigation with gasoline blends of butanol and propanol and magnesium partially stabilized zirconium (Mg-PSZ) as thermal barrier coating on piston crown of 100 µm. The samples of gasoline blends were blended with petrol in 1:4 ratios: 20 % of butanol and 80 % of gasoline; 20 % of propanol and 80 % of gasoline. In this work, the following engine characteristics of brake thermal efficiency (BTH), specific fuel consumption (SFC), HC, and CO emissions were measured for both coated and non-coated pistons. Experiments have shown that the thermal efficiency is increased by 2.2 % at P20. The specific fuel consumption is minimized by 2.2 % at P20. Exhaust emissions are minimized by 2.0 % of HC and 2.4 % of CO at B20. The results strongly indicate that the combination of thermal barrier coatings and gasoline blends can improve engine performance and reduce exhaust emissions.

scholarly journals Rancang Bangun dan Pengujian Penghalang Heliks sebagai Pencampur Udara-Biogas pada Motor Otto

2021 ◽  
Vol 8 (3) ◽  
pp. 89-96
Author(s):  
Herbert Hasudungan Siahaan ◽  
Armansyah H Tambunan ◽  
Desrial ◽  
Soni Solistia Wirawan
Keyword(s):  
Fuel Consumption ◽  
Performance Test ◽  
Engine Performance ◽  
Fuel Mixture ◽  
Specific Fuel Consumption ◽  
Combustion Reaction ◽  
Otto Cycle ◽  
Direct Use ◽  
Engine Power

A helical barrier as air-biogas mixing device was designed and tested for direct use of biogas from digester in otto cycle generator set. Homogeneity of the air-fuel mixture can give better combustion reaction and increase engine power. The design was based on simulation, which shows that a 0.039 m length of helical barrier gave a 5% increase in power compared to non-helical barrier. Likewise, the simulations also showed that the helical barrier reduced specific fuel consumption (SFC) by 8%. Accordingly, the mixer with helical barrier was designed, and fabricated. Its performance test confirms the improvement resulted by using helical barriers as air-biogas mixer in the engine. The experiment showed that the power increased by 5% when using helical barrier, while SFC decreased by 4.5%. It is concluded that the helical barrier can increase the homogeneity of the mixture resulting in better engine performance. Besides, emissions produced from the engine using a helical barrier also decreased.

Thermodynamics Cycle Analysis, Pressure Loss and Heat Transfer Assessment of a Recuperative System for Aero Engines

2014 ◽  
Author(s):  
A. Goulas ◽  
S. Donnerhack ◽  
M. Flouros ◽  
D. Misirlis ◽  
Z. Vlahostergios ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Fuel Consumption ◽  
Heat Exchangers ◽  
Engine Performance ◽  
Specific Fuel Consumption ◽  
Hot Gas ◽  
Research Activities ◽  
Aero Engine ◽  
Overall Efficiency ◽  
Aero Engines

Aiming in the direction of designing more efficient aero engines, various concepts have been developed in recent years, among which is the concept of an intercooled and recuperative aero engine. Particularly in the area of recuperation, MTU Aero Engines has been driving research activities in the last decade. This concept is based on the use of a system of heat exchangers mounted inside the hot-gas exhaust nozzle (recuperator). Through the operation of the system of heat exchangers, the heat from the exhaust gas, downstream the LP turbine of the jet engine is driven back to the combustion chamber. Thus, the preheated air enters the engine combustion chamber with increased enthalpy, providing improved combustion and by consequence, increased fuel economy and low-level emissions. If additionally an intercooler is placed between the compressor stages of the aero engine, the compressed air is then cooled by the intercooler thus, less compression work is required to reach the compressor target pressure. In this paper an overall assessment of the system is presented with particular focus on the recuperative system and the heat exchangers mounted into the aero engine’s exhaust nozzle. The herein presented results were based on the combined use of CFD computations, experimental measurements and thermodynamic cycle analysis. They focus on the effects of total pressure losses and heat exchanger efficiency on the aero engine performance especially the engine’s overall efficiency and the specific fuel consumption. More specifically, two different hot-gas exhaust nozzle configurations incorporating modifications in the system of heat exchangers are examined. The results show that significant improvements can be achieved in overall efficiency and specific fuel consumption hence contributing into the reduction of CO2 and NOx emissions. The design of a more sophisticated recuperation system can lead to further improvements in the aero engine efficiency in the reduction of fuel consumption. This work is part of the European funded research program LEMCOTEC (Low Emissions Core engine Technologies).

Effects of Micro-Emulsion Fuels on the Performance and Emissions of Diesel Engine

2011 ◽  
Vol 236-238 ◽  
pp. 151-154 ◽  
Author(s):  
Jia Quan Wang ◽  
Ping Sun ◽  
Zhen Chen ◽  
De Qing Mei
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Engine Performance ◽  
Specific Fuel Consumption ◽  
Performance And Emissions ◽  
Micro Emulsion ◽  
Effects Of Temperature ◽  
The Stability

The micro-emulsion fuels were prepared with complex surfactant, and the effects of temperature on the stability of these fuels were investigated. The engine performance and the emissions were studied when the engine was fueled with diesel and micro-emulsion diesel respectively. Results showed that when the engine was fueled with micro-emulsion diesel, the NOXand smoke emissions were decreased obviously and HC and CO emissions were increased slightly. Discounting of surfactant and water, the specific fuel consumption of micro-emulsion diesel was lower than those of diesel under any load at the speed of 2900r/min.

scholarly journals Effect of cetane improver addition into diesel fuel: Methanol mixtures on performance and emissions at different injection pressures

2017 ◽  
Vol 21 (1 Part B) ◽  
pp. 555-566 ◽  
Author(s):  
Feyyaz Candan ◽  
Murat Ciniviz ◽  
Ilker Ors
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Diesel Fuel ◽  
Engine Performance ◽  
Injection Pressure ◽  
Specific Fuel Consumption ◽  
Exhaust Emission ◽  
Brake Specific Fuel Consumption ◽  
Consumption Values ◽  
Smoke Opacity

In this study, methanol in ratios of 5-10-15% were incorporated into diesel fuel with the aim of reducing harmful exhaust gasses of Diesel engine, di-tertbutyl peroxide as cetane improver in a ratio of 1% was added into mixture fuels in order to reduce negative effects of methanol on engine performance parameters, and isobutanol of a ratio of 1% was used as additive for preventing phase separation of all mixtures. As results of experiments conducted on a single cylinder and direct injection Diesel engine, methanol caused the increase of NOx emission while reducing CO, HC, CO2, and smoke opacity emissions. It also reduced torque and power values, and increased brake specific fuel consumption values. Cetane improver increased torque and power values slightly compared to methanol-mixed fuels, and reduced brake specific fuel consumption values. It also affected exhaust emission values positively, excluding smoke opacity. Increase of injector injection pressure affected performances of methanol-mixed fuels positively. It also increased injection pressure and NOx emissions, while reducing other exhaust emissions.

scholarly journals ANALYSIS OF THE EFFECT OF BYPASS RATIO ON PERFORMANCE ENGINE CFM56-5A1 IN CRUISING CONDITIONS

Vortex ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 39
Author(s):  
Opri Surya Yustinoto
Keyword(s):  
Fuel Consumption ◽  
Engine Performance ◽  
Specific Fuel Consumption ◽  
Bypass Ratio ◽  
Consumption Value

The value of engine performance is known to decrease and increase with increasing and decreasing variation of the value of the parameter bypass ratio, so that if the value of these parameters is greater, then the fuel consumption when the aircraft operates will be less and the thrust will decrease. In addition to changing the value of the specific fuel consumption due to the influence of the bypass value, variations in altitude are also very influential where the higher the aircraft, the resulting specific fuel consumption value will be smaller 

scholarly journals ОСОБЕННОСТИ РАСЧЕТА И РЕГУЛИРОВАНИЯ ДВУХКОНТУРНОГО ТУРБОРЕАКТИВНОГО ДВИГАТЕЛЯ С ФОРСАЖНОЙ КАМЕРОЙ СГОРАНИЯ В НАРУЖНОМ КОНТУРЕ НА ПРЯМОТОЧНЫХ РЕЖИМАХ РАБОТЫ

2020 ◽  
pp. 15-23
Author(s):  
Олег Владимирович Кислов ◽  
Михаил Анатольевич Шевченко
Keyword(s):  
Mathematical Model ◽  
Fuel Consumption ◽  
Control Program ◽  
Critical Section ◽  
Specific Fuel Consumption ◽  
Outlet Section ◽  
Nozzle Outlet ◽  
Turbofan Engine ◽  
Turbofan Engines ◽  
Ramjet Engines

A promising direction in aviation is the creation of anaircraft for supersonic cruise speeds (Mach 3...4). It is known that ramjet engines are more preferable for Mach numbers larger 3. However, they do not have starting thrust and uneconomical at subsonic flight speeds. At the same time, at subsonic flight speeds, turbofan engines are the most expedient. The combination of the positive properties of turbofan engines at subsonic speeds and a ramjet engines at supersonic speeds is possible by using duct-burning turbofan engine, which can operate at the ramjet mode with the blocked gas turbine duct at supersonic flight conditions. At this mode, duct-burning turbofan engine turns into ramjet engine, which, however, has special features due to the presence of fan in front of the combustion chamber, which operates in turbine mode or in zero power mode and also because of the outlet jet, which has annular shape, flows out from the duct causes the appearance of bottom drag. The presence of bottom drag requires both the development of a mathematical model for its calculation and taking into account its influence on the choice of the control law for the nozzle outlet area. The article presents a mathematical model of the working process of duct-burning turbofan engine at ramjet mode, taking into account the presence of fan in the flow path and bottom drug. Using the developed mathematical model, the regularities of changes in the internal and effective thrust, as well as the specific fuel consumption, depending on the relative fuel consumption and the critical section of the nozzle at a given altitude and flight speed are established. The critical section of the nozzle is the main regulating factor, and the relative fuel consumption is related to the main regulating factor - the fuel consumption. These patterns are useful for choosing a control program.There is such a combination of regulating factors whichprovides two extremes in the regularities of trust and specific fuel consumption changes: the mode of minimum specific fuel consumption and the mode of maximum thrust. In addition, the influence of gas underexpansion in the nozzle on the thrust-economic parameters of the engine and the required area of the nozzle outlet section were estimated. The obtained regularities are advisable to use when engine control program is chosen.

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