scholarly journals Transport category airplane flight range calculation accounting center-of-gravity position shift and engine throttling characteristics

2021 ◽  
pp. 4-14
Author(s):  
Ruslan Tsukanov ◽  
Viktor Riabkov
Keyword(s):  
Mathematical Model ◽  
Fuel Consumption ◽  
Program Implementation ◽  
Fuel Efficiency ◽  
Real Data ◽  
Center Of Gravity ◽  
Specific Fuel Consumption ◽  
Flight Range ◽  
Position Shift ◽  
Range Calculation

A problem facing world commercial aviation is a provision of the flight range and an increase in the fuel efficiency of transport category airplanes using fuel trim transfer application, which allows for decreasing airplane trim drag at cruise flight. In the existing mathematical models, center-of-gravity position is usually assumed fixed, but with fuel usage, center-of-gravity shifts within the definite range of center-of-gravity positions. Until the fuel trim transfer was not used in airplanes, the center-of-gravity shift range was rather short, that allowed to use the specified assumption without any considerable mistakes. In case of fuel trim transfer use, center-of-gravity shifts can reach 15…20 % of mean aerodynamic chord, that requires considering the center-of-gravity actual position during the flight range calculation. Early made estimated calculations showed the necessity of following mathematical model improvement using accounting the real engine throttling characteristics. The goal of this publication is to develop a method of flight range calculation taking transport category airplane into account actual center-of-gravity position with fuel using and variation in engine-specific fuel consumption according to their throttling characteristics. On the basis of real data from engine maintenance manuals, formulas are obtained for approximation throttling characteristics of turbofan engines in the form of dimensionless specific fuel consumption (related to the specific fuel consumption at full thrust) dependence on the engine throttling coefficient. A mathematical model (algorithm and its program implementation using С language in Power Unit 11.7 R03 system) has been developed to calculate the airplane flight range accounting its actual center-of-gravity position shift with fuel usage and variation in specific fuel consumption according to engine throttling characteristics. Using comparison with known payload-range diagram, adequacy of developed mathematical model is shown. Recommendations to improve the mathematical model are also given.

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.

scholarly journals Optimisation of the vehicle transmission and the gear-shifting strategy for the minimum fuel consumption and the minimum nitrogen oxide emissions

2017 ◽  
Vol 231 (7) ◽  
pp. 883-899 ◽  
Author(s):  
Callum J Oglieve ◽  
Mahdi Mohammadpour ◽  
Homer Rahnejat
Keyword(s):  
Nitrogen Oxide ◽  
Fuel Consumption ◽  
Fuel Efficiency ◽  
Specific Fuel Consumption ◽  
Brake Specific Fuel Consumption ◽  
Objective Functions ◽  
Computationally Efficient ◽  
Nitrogen Oxide Emissions ◽  
Case Scenario ◽  
Shifting Strategy

The paper outlines a computationally efficient analytical method for evaluating the fuel consumption and the nitrogen oxide emissions during manoeuvres pertaining to the New European Driving Cycle. An integrated optimisation procedure is also included in the analyses with minimisation of the brake specific fuel consumption and minimisation of the nitrogen oxide emissions as objective functions. A set of optimum gear ratios are determined for a four-speed transmission, a five-speed transmission and six-speed transmission as the governing parameters in the optimisation process. The analysis highlights the determination of gear-shifting objective-driven strategies based on the minimisation of either of the declared objective functions. A reduction of 7.5% in the brake specific fuel consumption and a reduction of 6.75% in nitrogen oxide emissions are attainable in the best-case scenario for a six-speed transmission and a gear-shifting strategy based on the lowest brake specific fuel consumption for the case of an engine. The novel integrated analytical simulations and multi-objective optimisation have not been hitherto reported in literature. It provides the opportunity for an objective intelligent-based approach to the use of gear shift indicator technology. The results of this study also show that transmission optimisation can act as an effective and inexpensive mean to enhance the fuel efficiency and to reduce the emissions.

scholarly journals Mathematical model for calculating the mass of a heat exchanger in problems of optimizing the parameters of the working process of aircraft gas turbine engines

2019 ◽  
Vol 18 (3) ◽  
pp. 67-80
Author(s):  
V. S. Kuz'michev ◽  
H. Omar ◽  
A. Yu. Tkachenko ◽  
A. A. Bobrik
Keyword(s):  
Mathematical Model ◽  
Heat Exchanger ◽  
Gas Turbine ◽  
Fuel Consumption ◽  
Heat Recovery ◽  
Specific Weight ◽  
Specific Fuel Consumption ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbine Engine

Despite the fact that aviation gas turbine engines (GTE) have reached a high degree of sophistication, requirements for the improvement of their efficiency are constantly increasing. Reduction of specific fuel consumption and specific weight of the engine unit makes it possible to improve aircraft performance. One of the effective means of reducing specific fuel consumption and obtaining high thermal efficiency of a gas turbine engine is the use of heat recovery, so the interest in it holds throughout the period of development of gas turbine engines. However, the use of heat recovery in aircraft gas turbine engines is faced with a contradiction: on the one hand, heat recovery allows reducing specific fuel consumption, but, on the other hand, it increases the weight of the power plant due to the presence of a heat exchanger. Moreover, with the increase in the degree of regeneration, specific fuel consumption decreases, whereas the mass of the power plant increases.To obtain the desired effect, it is necessary to optimize simultaneously both the parameters of the engine work process and the degree of regeneration of the heat exchanger according to the criteria of evaluating the engine unit in the aircraft system. For this purpose, it is necessary to have a mathematical model for estimating the weight of a highly efficient aircraft heat exchanger. The article presents a developed mathematical model for calculating the weight of a compact plate heat exchanger used to increase the efficiency of a gas turbine engine due to the heating of compressed air entering the combustion chamber by the hot gas that enters the combustion chamber from behind the turbine. We chose a rational pattern of relative motion of the working media in the heat exchanger, the optimal type of plate-type heat transfer surface in terms of minimizing the weight of the heat exchanger and the hydraulic losses in the air and gas ducts. For the selected surface type, the dependence of the specific weight of the heat exchanger on the degree of regeneration is determined for different nozzle exhaust velocities on the basis of a computational algorithm. To assess the reliability of the obtained model, comparative analysis of the effect of the degree of regeneration on the specific weight of the heat exchanger was carried out, based on the comparison of the results of calculations for the developed model with the data of other authors and with the data for the produced regenerators.

scholarly journals ОЦІНКА ВПЛИВУ ЦЕНТРУВАННЯ НА АЕРОДИНАМІЧНУ ЯКІСТЬ, ПОЛЯРУ І ДАЛЬНІСТЬ ПОЛЬОТУ ЛІТАКА

2021 ◽  
pp. 135-145
Author(s):  
Ruslan U. Tsukanov ◽  
Victor I. Ryabkov
Keyword(s):  
Quantitative Estimation ◽  
Fuel Efficiency ◽  
Center Of Gravity ◽  
Fuel Utilization ◽  
Engine Thrust ◽  
Flight Range ◽  
Flight Mode ◽  
Range Transport ◽  
Drag Ratio ◽  
Lift To Drag Ratio

The method of transport category airplane flight range estimation taking into account its center-of-gravity position variation in the process of fuel utilization at cruising flight mode is presented. The method structure includes the following models:– Interinfluence of main parameters on each other in the process of fuel utilization;– Estimation of CG position influence on lift-to-drag ratio in cruising mode;– Quantitative estimation of center-of-gravity position variation influence on airplane flight range.Simulation of the main parameters is based on authoring researches, establishing interinfluence among geometrical and aerodynamic parameters of wing, parameters of horizontal tail and center-of-gravity position variation caused by fuel utilization in cruise flight. Such model allows estimating airplane center-of-gravity influence on their values and relative position.Aerodynamic parameters variation caused by center-of-gravity shift resulted in necessity to take the influence into account, for required engine thrust variation; that is shown in the publication in the form of dependences  allowing to take into account the required thrust variation and their influence on range variation.On the base of interinfluence model and taking into account required thrust variation (with center-of-gravity position shift), lift-to-drag variation has been obtained and analyzed in the form of dependences ,  for middle airplane of transport category.Expression for estimation of airplane flight range under variable values of its mass and center-of-gravity position is obtained on the base of these models; that allows to increase flight range by means of center-of-gravity position dedicated shift.On the example of mid-range transport airplane, it is shown, that at Mach number  and center-of-gravity shift back from  to , the increase of flight range makes .On the base of presented models, it is shown, that airplane center-of-gravity position influences lift-to-drag ratio, fuel efficiency and as a result on flight range at cruising flight mode.Application of aft center-of-gravity position allows to decrease engine required thrust (and to decrease fuel consumption), and increase lift-to-drag ratio and airplane flight range.

scholarly journals ВПЛИВ ЗМІНИ ЦЕНТРУВАННЯ НА ДАЛЬНІСТЬ ПОЛЬОТУ ЛІТАКА ТРАНСПОРТНОЇ КАТЕГОРІЇ

2020 ◽  
pp. 5-14
Author(s):  
R. Tsukanov ◽  
V. Ryabkov ◽  
O. Los
Keyword(s):  
Quantitative Estimation ◽  
Fuel Efficiency ◽  
Center Of Gravity ◽  
Fuel Utilization ◽  
Engine Thrust ◽  
Flight Range ◽  
Flight Mode ◽  
Range Transport ◽  
Drag Ratio ◽  
Lift To Drag Ratio

The method of transport category airplane flight range estimation taking into account its center-of-gravity position variation in the process of fuel utilization at cruising flight mode is presented. The method structure includes the following models:– Interinfluence of main parameters on each other in the process of fuel utilization;– CG position influence on required thrust values in level flight;– Estimation of CG position influence on lift-to-drag ratio in cruise mode;– Quantitative estimation of center-of-gravity position variation influence on airplane flight range.Simulation of the main parameters is based on authoring researches, which established interinfluence among geometrical and aerodynamic parameters of wing, parameters of horizontal tail and center-of-gravity position variation caused by fuel utilization in cruise flight. Such model allows estimating of airplane center-of-gravity influence their values and their relative position.Aerodynamic parameters variation caused by center-of-gravity shift resulted in necessity to take this influence into account, for required engine thrust variation; that is shown in the publication in the form of dependences P(M, m, xCG) allowing to take into account the required thrust variation and their influence to range variation.On the base of interinfluence model and taking into account required thrust variation (when center-of-gravity position shifts), lift-to-drag variation has been obtained and analyzed in the form of dependences K, KM(M, m, xCG) for middle airplane of transport category.Expression for estimation of airplane flight range under variable values of its mass and center-of-gravity position is obtained on the base of these models; that allows flight range increasing by means of center-of-gravity position dedicated shift.On the example of mid-range transport airplane, it is shown, that at Mach number M = 0.7 and center-of-gravity shift back from xCG = 0.20 to xCG = 0.35, the increase of lift-to-drag ratio makes ΔK = 0.43.On the base of presented models, it is shown, that airplane center-of-gravity position influences lift-to-drag ratio, fuel efficiency and as a result on flight range at cruising flight mode.Application of aft center-of-gravity position allows decreasing of engine required thrust (decreasing fuel consumption), and increasing of lift-to-drag ratio and airplane flight range.

Modifications to Improve Fuel Consumption in the Remanufacture of Spark Ignition Engines for Electric Generators

2015 ◽  
Author(s):  
Matthew Neill Swain ◽  
Oliver Patrick Jordan ◽  
Travis Jamal Mackey ◽  
Patrick Shannon Seemann ◽  
Hasitha Samarajeewa ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Internal Combustion Engines ◽  
Fuel Efficiency ◽  
Spark Ignition ◽  
Specific Fuel Consumption ◽  
Phase Iii ◽  
Brake Specific Fuel Consumption ◽  
Test Cycle ◽  
Automotive Engines ◽  
Electric Generators

This paper describes the development of a water cooled, lean burn, gaseous fueled engine designed for distributed power installations. Electric generators have become popular because they provide a portable supply of electrical power at consumer demand. They are used in critical need areas such as hospitals and airports, and have found their way into homes frequented with power outages or homes in remote locations. Gensets are available in a wide variety of sizes ranging from 1 kilowatt (kW) to thousands of kilowatts. In the mid-range the power sources are typically spark ignition, automotive type internal combustion engines. Since engines designed for automotive use are subject to different emission regulations, and are optimized for operation at RPMs and BMEPs above that of electric generator engines, modifications can be made to optimize them for gensets. This work describes modifications which can be made during remanufacturing an automotive engine to optimize it for use as a generator engine. While the work recognizes the potential for cost savings from the use of remanufactured automotive engines over that of using new automotive engines and the majority of the design constraints were adopted to reduce engine cost, the main focus of the work is quantifying the increase in fuel efficiency that can be achieved while meeting the required EPA emission requirements. This paper describes the seven combustion chamber designs that were developed and tested during this work. Friction reduction was obtained in both valve train and journal bearing design. The engine optimized for fuel efficiency produced a maximum brake thermal efficiency of 37.5% with λ= 1.63. This yielded an EPA test cycle average brake specific fuel consumption (BSFC) of 325 g/kW-hr. Modification of the spark advance and low load equivalence ratio to meet EPA Phase III emission standards resulted in an EPA test cycle average BSFC of 330 gm/kW-hr. When the engine used in this research was tested in its unmodified, automotive configuration under the EPA Compliant Test Cycle it’s EPA test cycle average brake specific fuel consumption was 443.4 gm/kW-hr. This is a 34% increase in fuel consumption compared to the modified engine.

Application of Box-Behnken Analysis on the Optimisation of Air Intake System for a Naturally Aspirated Engine

2020 ◽  
Vol 17 (2) ◽  
pp. 8029-8042
Author(s):  
N.S. Mustafa ◽  
N.H.A. Ngadiman ◽  
M.A. Abas ◽  
M.Y. Noordin
Keyword(s):  
Fuel Consumption ◽  
Fuel Efficiency ◽  
Engine Performance ◽  
Fuel Price ◽  
Design Expert ◽  
Intake System ◽  
Analysis Technique ◽  
System Components ◽  
Air Intake ◽  
High Influence

Fuel price crisis has caused people to demand a car that is having a low fuel consumption without compromising the engine performance. Designing a naturally aspirated engine which can enhance engine performance and fuel efficiency requires optimisation processes on air intake system components. Hence, this study intends to carry out the optimisation process on the air intake system and airbox geometry. The parameters that have high influence on the design of an airbox geometry was determined by using AVL Boost software which simulated the automobile engine. The optimisation of the parameters was done by using Design Expert which adopted the Box-Behnken analysis technique. The result that was obtained from the study are optimised diameter of inlet/snorkel, volume of airbox, diameter of throttle body and length of intake runner are 81.07 mm, 1.04 L, 44.63 mm and 425 mm, respectively. By using these parameters values, the maximum engine performance and minimum fuel consumption are 93.3732 Nm and 21.3695×10-4 kg/s, respectively. This study has fully accomplished its aim to determine the significant parameters that influenced the performance of airbox and optimised the parameters so that a high engine performance and fuel efficiency can be produced. The success of this study can contribute to a better design of an airbox.

THE DEVELOPMENT OF THE MATHEMATICAL MODEL OF PREDICTING THE INDICATORS OF ACCREDITATION OF TECHNICAL UNIVERSITIES IN THE RUSSIAN FEDERATION

2017 ◽  
pp. 27-38
Author(s):  
Olga Mikhaylovna Tikhonova ◽  
Alexander Fedorovich Rezchikov ◽  
Vladimir Andreevich Ivashchenko ◽  
Vadim Alekseevich Kushnikov
Keyword(s):  
Mathematical Model ◽  
System Dynamics ◽  
Regression Model ◽  
Oriented Graph ◽  
Real Data ◽  
Educational Process ◽  
Proposed Model ◽  
Linear Differential ◽  
The University ◽  
The Mathematical Model

The paper presents the system of predicting the indicators of accreditation of technical universities based on J. Forrester mechanism of system dynamics. According to analysis of cause-and-effect relationships between selected variables of the system (indicators of accreditation of the university) there was built the oriented graph. The complex of mathematical models developed to control the quality of training engineers in Russian higher educational institutions is based on this graph. The article presents an algorithm for constructing a model using one of the simulated variables as an example. The model is a system of non-linear differential equations, the modelling characteristics of the educational process being determined according to the solution of this system. The proposed algorithm for calculating these indicators is based on the system dynamics model and the regression model. The mathematical model is constructed on the basis of the model of system dynamics, which is further tested for compliance with real data using the regression model. The regression model is built on the available statistical data accumulated during the period of the university's work. The proposed approach is aimed at solving complex problems of managing the educational process in universities. The structure of the proposed model repeats the structure of cause-effect relationships in the system, and also provides the person responsible for managing quality control with the ability to quickly and adequately assess the performance of the system.

Exergy analysis of a turboprop engine at different flight altitude and speeds using novel consideration

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali Dinc ◽  
Yousef Gharbia
Keyword(s):  
Fuel Consumption ◽  
Thermal Efficiency ◽  
Exergy Efficiency ◽  
Specific Fuel Consumption ◽  
Flight Altitude ◽  
Fuel Flow ◽  
Turboprop Engine ◽  
Shaft Power ◽  
Two Parameters ◽  
The Relationship

Abstract In this study, exergy efficiency calculations of a turboprop engine were performed together with main performance parameters such as shaft power, specific fuel consumption, fuel flow, thermal efficiency etc., for a range of flight altitude (0–14 km) and flight speeds (0–0.6 Mach). A novel exergy efficiency formula was derived in terms of specific fuel consumption and it is shown that these two parameters are inversely proportional to each other. Moreover, a novel exergy efficiency and thermal efficiency relation was also derived. The relationship showed that these two parameters are linearly proportional to each other. Exergy efficiency of the turboprop engine was found to be in the range of 23–33%. Thermal efficiency of the turboprop engine was found to be around 25–35%. Exergy efficiency is higher at higher speeds and altitude where the specific fuel consumption is lower. Conversely, exergy efficiency of the engine is lower for lower speeds and altitude where the specific fuel consumption is higher.

scholarly journals Effect of Methanol/Water Mixed Fuel Compound Injection on Engine Combustion and Emissions

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4491
Author(s):  
Changchun Xu ◽  
Haengmuk Cho
Keyword(s):  
Fuel Consumption ◽  
Ignition Delay ◽  
Fuel Injection ◽  
Fuel Efficiency ◽  
Engine Performance ◽  
Hydroxyl Group ◽  
Combustion Mechanism ◽  
Performance And Emission ◽  
Reduce Emissions ◽  
Concentration Ratios

Due to the recent global increase in fuel prices, to reduce emissions from ground transportation and improve urban air quality, it is necessary to improve fuel efficiency and reduce emissions. Water, methanol, and a mixture of the two were added at the pre-intercooler position to keep the same charge and cooling of the original rich mixture, reduce BSFC and increase ITE, and promote combustion. The methanol/water mixing volume ratios of different fuel injection strategies were compared to find the best balance between fuel consumption, performance, and emission trends. By simulating the combustion mechanism of methanol, water, and diesel mixed through the Chemkin system, the ignition delay, temperature change, and the generation rate of the hydroxyl group (−OH) in the reaction process were analyzed. Furthermore, the performance and emission of the engine were analyzed in combination with the actual experiment process. This paper studied the application of different concentration ratios of the water–methanol–diesel mixture in engines. Five concentration ratios of water–methanol blending were injected into the engine at different injection ratios at the pre-intercooler position, such as 100% methanol, 90% methanol/10% water, 60% methanol/40% water, 30% methanol/70% water, 100% water was used. With different volume ratios of premixes, the combustion rate and combustion efficiency were affected by droplet extinguishment, flashing, or explosion, resulting in changes in combustion temperature and affecting engine performance and emissions. In this article, the injection carryout at the pre-intercooler position of the intake port indicated thermal efficiency increase and a brake specific fuel consumption rate decrease with the increase of water–methanol concentration, and reduce CO, UHC, and nitrogen oxide emissions. In particular, when 60% methanol and 40% water were added, it was found that the ignition delay was the shortest and the cylinder pressure was the largest, but the heat release rate was indeed the lowest.

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