scholarly journals Comprehensive Performance Analysis for the Rotating Detonation-Based Turboshaft Engine

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Zifei Ji ◽  
Ruize Duan ◽  
Renshuai Zhang ◽  
Huiqiang Zhang ◽  
Bing Wang
Keyword(s):  
Performance Analysis ◽  
Fuel Consumption ◽  
Thermal Efficiency ◽  
Pressure Ratio ◽  
Specific Fuel Consumption ◽  
Specific Power ◽  
Compressor Pressure Ratio ◽  
Comprehensive Performance ◽  
Turboshaft Engine ◽  
Rotating Detonation

The potential advantages of rotating detonation combustion are gradually approved, and it is becoming a stable and controllable energy conversion way adopted to the propulsion devices or ground-engines. This study focuses on the rotating detonation-based turboshaft engine, and the architecture is presented for this form of engine with compatibility between the turbomachinery and rotating detonation combustor being realized. The parametric performance simulation model for the rotating detonation-based turboshaft engine are developed. Further, the potential performance benefits as well as their generation mechanism are revealed, based on the comprehensive performance analysis of the rotating detonation-based turboshaft engine. Comparisons between the rotating detonation turboshaft engine and the conventional one reveal that the former holds significant improvements in specific power, thermal efficiency, and specific fuel consumption at lower compressor pressure ratios, and these improvements decrease with the increase of compressor pressure ratio and increase as turbine inlet temperature increases. The critical compressor pressure ratio corresponding to the disappearance of specific power improvement is higher than that corresponding to the disappearance of thermal efficiency and specific fuel consumption. These critical compressor pressure ratios are positively correlated with flight altitude and negatively correlated with flight velocity. The conductive research conclusion is guidable for the design and engineering application of rotating detonation-based engines.

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.

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 Advanced Turboprop Engines for Long Endurance Naval Patrol Aircraft

1982 ◽  
Author(s):  
R. Hirschkron ◽  
R. H. Davis
Keyword(s):  
Pressure Drop ◽  
Fuel Consumption ◽  
Pressure Ratio ◽  
Specific Fuel Consumption ◽  
Performance Requirements ◽  
The Future ◽  
Weight Design ◽  
Long Endurance

Long endurance naval patrol aircraft of the future will require more efficient advanced turboprop powerplants. Engines used in this kind of application will have performance requirements emphasizing prolonged endurance and very low specific fuel consumption for cruise and part-power loiter operation. Regenerative, regenerative/intercooled and advanced conventional cycle screening studies were carried out to select the cycle pressure ratio and turbine temperature for each type, considering the effects on installed performance and weight. Design and cycle choices were studied in each engine category including recuperator types, effectiveness, pressure drop, bypass bleed and variable area turbine nozzle. The engine characteristics of each type were then compared using a representative mission. The advanced conventional engine showed the largest potential, the regenerative second and the regenerative/intercooled the least promise for lower installed fuel consumption and improved mission performance.

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 EXPERIMENTAL ANALYSIS OF THE COMBUSTION CHAMBER COATED WITH Mo AND Al2O3-TiO2 IN A DIESEL ENGINE

2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Murugan Kuppusamy ◽  
Thirumalai Ramanathan ◽  
Udhayakumar Krishnavel ◽  
Seenivasan Murugesan
Keyword(s):  
Combustion Chamber ◽  
Fuel Consumption ◽  
Thermal Efficiency ◽  
Performance Test ◽  
Ceramic Powder ◽  
Specific Fuel Consumption ◽  
Emission Characteristic ◽  
Powder Materials ◽  
Brake Specific Fuel Consumption ◽  
Brake Thermal Efficiency

The effect of thermal-barrier coatings (TBCs) reduces fuel consumption, effectively improving the engine efficiency. This research focused on a TBC with a thickness of 300 µm insulating the combustion chamber of a direct ignition (DI) engine. The piston crown, inlet and exhaust-valve head were coated using air-plasma-spray coating. Ceramic powder materials such as molybdenum (Mo) and aluminum oxide titanium dioxide (Al2O3-TiO2) were used. A performance test of the engine with the coated combustion chamber was carried out to investigate the brake power, brake thermal efficiency, volumetric efficiency, brake specific fuel consumption and air-fuel ratio. Also, an emission-characteristic test was carried out to investigate the emissions of unburned hydrocarbon (HC), carbon monoxide (CO), nitrogen oxides (NO, NO2, NO3) and smoke opacity (SO). The results reveal that the brake thermal efficiency and brake specific fuel consumption show significant increases because of these coating materials. The effect of the Al2O3-TiO2 coating significantly reduces the HC and CO engine emissions.

Multidisciplinary Analysis of a Geared Fan Intercooled Core Aero-Engine

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Konstantinos G. Kyprianidis ◽  
Andrew M. Rolt ◽  
Tomas Grönstedt
Keyword(s):  
Exchange Rates ◽  
Fuel Consumption ◽  
Pressure Ratio ◽  
Velocity Ratio ◽  
Specific Fuel Consumption ◽  
Design Parameters ◽  
Aircraft Model ◽  
Aero Engine ◽  
Jet Velocity ◽  
Analytical Expressions

The reduction of CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, along with the reduction of engine nacelle drag and weight. One alternative design approach to improving specific fuel consumption is to consider a geared fan combined with an increased overall pressure ratio intercooled core performance cycle. The thermal benefits from intercooling have been well documented in the literature. Nevertheless, there is very little information available in the public domain with respect to design space exploration of such an engine concept when combined with a geared fan. The present work uses a multidisciplinary conceptual design tool to analyze the option of an intercooled core geared fan aero engine for long haul applications with a 2020 entry into service technology level assumption. With minimum mission fuel in mind, the results indicate as optimal values a pressure ratio split exponent of 0.38 and an intercooler mass flow ratio of 1.18 at hot-day top of climb conditions. At ISA midcruise conditions a specific thrust of 86 m/s, a jet velocity ratio of 0.83, an intercooler effectiveness of 56%, and an overall pressure ratio value of 76 are likely to be a good choice. A 70,000 lbf intercooled turbofan engine is large enough to make efficient use of an all-axial compression system, particularly within a geared fan configuration, but intercooling is perhaps more likely to be applied to even larger engines. The proposed optimal jet velocity ratio is actually higher than the value one would expect by using standard analytical expressions, primarily because this design variable affects core efficiency at mid-cruise due to a combination of several different subtle changes to the core cycle and core component efficiencies at this condition. The analytical expressions do not consider changes in core efficiency and the beneficial effect of intercooling on transfer efficiency, nor do they account for losses in the bypass duct and jet pipe, while a relatively detailed engine performance model, such as the one utilized in this study, does. Mission fuel results from a surrogate model are in good agreement with the results obtained from a rubberized-wing aircraft model for some of the design parameters. This indicates that it is possible to replace an aircraft model with specific fuel consumption and weight penalty exchange rates. Nevertheless, drag count exchange rates have to be utilized to properly assess changes in mission fuel for those design parameters that affect nacelle diameter.

Analyses and Optimization of a Propulsion Cycle for Unmixed High Bypass Turbofan

2008 ◽  
Author(s):  
Adel Ghenaiet
Keyword(s):  
Fuel Consumption ◽  
Pressure Ratio ◽  
Specific Fuel Consumption ◽  
Design Parameters ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
High Pressure Ratio ◽  
Turbine Inlet ◽  
Design Variables ◽  
Bypass Ratio

This paper deals with a parametric study and an optimization for the design variables of a high bypass unmixed turbofan equipping commercial aircrafts. The objective of the first part of this study is to highlight the effects of the principal design parameters (bypass ratio, compression ratios, turbine inlet temperature etc..) on the uninstalled performance, in terms of specific thrust and specific fuel consumption. The second part concerns the optimization, aiming at finding the optimum design parameters concurrently minimizing the specific fuel consumption at cruise, and meeting the thrust requirement at takeoff. The cycle analyzer (on-design and off-design) as coupled to the optimization algorithm MMFD by adopting a random multi-starts search strategy is shown to be stable and converging. The predefined requirements and constraints have dictated utilizing an engine with a high-bypass ratio, high-pressure ratio and a moderate turbine inlet temperature. In general, the obtained results compare fairly well with typical data available for an equivalent ‘reference’ engine. This elaborated methodology is shown to be consistent with the conceptual design requirements and accuracy, because, it does not use components’ characteristics, and operates on simplifying assumptions. This present methodology can be readily adapted for other configurations of aero-engines as well, and easily integrated in a multi-disciplinary design approach.

Impact of Oxidation Inhibitors on Performance and Emission Characteristics of a Low Heat Rejection Engine

2017 ◽  
Vol 8 (4) ◽  
Author(s):  
P.S. Kumar ◽  
S.A. Kannan ◽  
A. Kumar ◽  
K.A.V. Geethan
Keyword(s):  
Combustion Chamber ◽  
Fuel Consumption ◽  
Thermal Efficiency ◽  
Specific Fuel Consumption ◽  
Nox Emission ◽  
Emission Characteristics ◽  
Brake Thermal Efficiency ◽  
Heat Rejection ◽  
Oxidation Inhibitors ◽  
Low Heat Rejection Engine

In this study, for the first time analysis of a low heat rejection engine was carried out along with the addition of oxidation inhibitors. If the combustion chamber components of the engine such as piston, cylinder head, and inlet and outlet valves are insulated with a thermal barrier material, then the engine will be referred as low heat rejection engine. In this study yttria stabilized zirconia was coated on the combustion chamber components for a thickness of about 150 microns. Then the analysis of performance parameters such as brake thermal efficiency and specific fuel consumption and emission characteristics such as emission of carbon monoxide, hydrocarbon and nitrogen oxide was carried out in single cylinder four stroke diesel engine with electrical loading using diesel and pongamia methyl ester as the fuels. The major problem associated with the usage of biodiesels and low heat rejection engine is the increased NOX emission than the normal engine operated with the diesel. This problem has been overcome by the usage of oxidation inhibitors such as ethyl hexyl nitrate (EHN), tert-butyl hydroquinone (TBHQ). The results showed that addition of oxidation inhibitors leads to increase in brake thermal efficiency, reduced specific fuel consumption and reduced NOX emission.

Fundamental Differences Between Conventional and Geared Turbofans

2009 ◽  
Author(s):  
Joachim Kurzke
Keyword(s):  
Fuel Consumption ◽  
Real Option ◽  
Pressure Ratio ◽  
Thermodynamic Cycle ◽  
Specific Fuel Consumption ◽  
Thermodynamic Efficiency ◽  
Aircraft Engines ◽  
Direct Drive ◽  
Significant Difference ◽  
Bypass Ratio

The potential for improving the thermodynamic efficiency of aircraft engines is limited because the aerodynamic quality of the turbomachines has already achieved a very high level. While in the past increasing burner exit temperature did contribute to better cycle efficiency, this is no longer the case with today’s temperatures in the range of 1900...2000K. Increasing the cycle pressure ratio above 40 will yield only a small fuel consumption benefit. Therefore the only way to improve the fuel efficiency of aircraft engines significantly is to increase bypass ratio — which yields higher propulsive efficiency. A purely thermodynamic cycle study shows that specific fuel consumption decreases continuously with increasing bypass ratio. However, thermodynamics alone is a too simplistic view of the problem. A conventional direct drive turbofan of bypass ratio 6 looks very different to an engine with bypass ratio 10. Increasing bypass ratio above 10 makes it attractive to design an engine with a gearbox to separate the fan speed from the other low pressure components. Different rules apply for optimizing turbofans of conventional designs and those with a gearbox. This paper describes various criteria to be considered for optimizing the respective engines and their components. For illustrating the main differences between conventional and geared turbofans it is assumed that an existing core of medium pressure ratio with a two stage high pressure turbine is to be used. The design of the engines is done for takeoff rating because this is the mechanically most challenging condition. For each engine the flow annulus is examined and stress calculations for the disks are performed. The result of the integrated aero-thermodynamic and mechanical study allows a comparison of the fundamental differences between conventional and geared turbofans. At the same bypass ratio there will be no significant difference in specific fuel consumption between the alternative designs. The main difference is in the parts count which is much lower for the geared turbofan than for the conventional engine. However, these parts will be mechanically much more challenging than those of a conventional turbofan. If the bypass ratio is increased significantly above 10, then the geared turbofan becomes more and more attractive and the conventional turbofan design is no longer a real option. The maximum practical bypass ratio for ducted fans depends on the nacelle drag and how the installation problems can be solved.

The Comparative Trail Research on the Performance of a Diesel Engine Fuelled with Diesel Fuel and Biodiesel/Diesel Blended Fuel

2011 ◽  
Vol 142 ◽  
pp. 103-106
Author(s):  
Wen Ming Cheng ◽  
Hui Xie ◽  
Gang Li
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Diesel Fuel ◽  
Thermal Efficiency ◽  
Specific Fuel Consumption ◽  
Brake Specific Fuel Consumption ◽  
Brake Thermal Efficiency ◽  
Series Of Experiments ◽  
Blended Fuel ◽  
Load Conditions

This paper discusses the brake specific fuel consumption and brake thermal efficiency of a diesel engine using cottonseed biodiesel blended with diesel fuel. A series of experiments were conducted for the various blends under varying load conditions at a speed of 1500 rpm and 2500 rpm and the results were compared with the neat diesel. From the results, it is found that the brake specific fuel consumption of cottonseed biodiesel is slightly higher than that of diesel fuel at different engine loads and speeds, with this increase being higher the higher the percentage of the biodiesel in the blend. And the brake thermal efficiency of cottonseed biodiesel is nearly similar to that of diesel fuel at different engine loads and speeds. From the investigation, it is concluded that cottonseed biodiesl can be directly used in diesel engines without any modifications, at least in small blending ratios.

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