Effects of Bypass Ratio Change Trend on Performance in a Military Aircraft Turbofan Engine with Comparative Assessment

Steam power plant Generation of Tanjung Jati B 3rd unit has a capacity of 660 MW. The power plant operational in 2011, because of the long operation process, there will be a decrease in performance. The plant needs to be researched to analyze the performance and losses that occurs in the power plant. Because this also affects the environment if the efficiency of the power plant is high, it can reduce the use of coal. Because coal becomes air pollution and environmental pollution, which can cause acid rain, water pollution, and global warming. This research is used to analyze energy and exergy on the components of a steam power plant. From the results of this research, the largest of destruction exergy boiler is 881.08 MW and the exergetic efficiency is 48.66%. While the rate of the smallest destruction exergy in LPH 3 is 0.6 MW and the exergetic efficiency is 94.45%. The contribution of the largest Losses energy in the boiler is 231 MW and energetic efficiency is 87.05%. While the contribution of the smallest energy Losses in HPH 6 is 0.74 MW and energetic efficiency is 99.23%.

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THERMODYNAMIC ANALYSES OF MULTIPLE EVAPORATORS VAPOR COMPRESSION REFRIGERATION SYSTEMS WITH R410A, R290, R1234YF, R502, R404A, R152A AND R134A

International Journal of Air-Conditioning and Refrigeration ◽

10.1142/s2010132514500035 ◽

2014 ◽

Vol 22 (01) ◽

pp. 1450003 ◽

Cited By ~ 8

Author(s):

KAPIL CHOPRA ◽

V. SAHNI ◽

R. S. MISHRA

Keyword(s):

Numerical Model ◽

Thermodynamic Analysis ◽

Energetic Efficiency ◽

Vapor Compression ◽

Exergetic Efficiency ◽

System Defect ◽

Energy And Exergy ◽

System 2 ◽

Vapor Compression Refrigeration ◽

System 1

In this paper, comparative thermodynamic analysis of system-1 (multiple evaporators and compressors with individual expansion valves) and system-2 (multiple evaporators and compressors with multiple expansion valves) has been presented which is based on energy and exergy principles. The comparison of systems-1 and -2 using ecofriendly R410A, R290, R1234YF, R502, R404A, R152A and R134A refrigerants was done in terms of COP (energetic efficiency), exergetic efficiency and system defect. Numerical model has been developed for systems-1 and -2 for finding out irreversibility and it was observed that system-2 is better system in comparison with system-1 for selected refrigerants. It was also found that R152a shows better performances than other considered refrigerants for both systems.

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THREE-DIMENSIONAL FLOW IN A TRANSONIC AXIAL FLOW FAN OF A HIGH BYPASS RATIO TURBOFAN ENGINE

International Conference on Aerospace Sciences and Aviation Technology ◽

10.21608/asat.2011.27139 ◽

2011 ◽

Vol 11 (ASAT CONFERENCE) ◽

pp. 1-21

Author(s):

A. ABD EL-AZIM ◽

M. GOBRAN ◽

H. HASSAN

Keyword(s):

Three Dimensional ◽

Axial Flow ◽

Axial Flow Fan ◽

Three Dimensional Flow ◽

Turbofan Engine ◽

Dimensional Flow ◽

Bypass Ratio

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A Comparative Study of Genetic Algorithms and Gradient Methods for RM12 Turbofan Engine Diagnostics and Performance Estimation

Volume 2: Turbo Expo 2004 ◽

10.1115/gt2004-53591 ◽

2004 ◽

Cited By ~ 7

Author(s):

Tomas Gro¨nstedt ◽

Markus Wallin

Keyword(s):

Gas Turbine ◽

Performance Test ◽

Gradient Methods ◽

Performance Testing ◽

Performance Estimation ◽

Data Sets ◽

Data Set ◽

Turbofan Engine ◽

Local Optima ◽

Bypass Ratio

Recent work on gas turbine diagnostics based on optimisation techniques advocates two different approaches: 1) Stochastic optimisation, including Genetic Algorithm techniques, for its robustness when optimising objective functions with many local optima and 2) Gradient based methods mainly for their computational efficiency. For smooth and single optimum functions, gradient methods are known to provide superior numerical performance. This paper addresses the key issue for method selection, i.e. whether multiple local optima may occur when the optimisation approach is applied to real engine testing. Two performance test data sets for the RM12 low bypass ratio turbofan engine, powering the Swedish Fighter Gripen, have been analysed. One set of data was recorded during performance testing of a highly degraded engine. This engine has been subjected to Accelerated Mission Testing (AMT) cycles corresponding to more than 4000 hours of run time. The other data set was recorded for a development engine with less than 200 hours of operation. The search for multiple optima was performed starting from more than 100 extreme points. Not a single case of multi-modality was encountered, i.e. one unique solution for each of the two data sets was consistently obtained. The RM12 engine cycle is typical for a modern fighter engine, implying that the obtained results can be transferred to, at least, most low bypass ratio turbofan engines. The paper goes on to describe the numerical difficulties that had to be resolved to obtain efficient and robust performance by the gradient solvers. Ill conditioning and noise may, as illustrated on a model problem, introduce local optima without a correspondence in the gas turbine physics. Numerical methods exploiting the special problem structure represented by a non-linear least squares formulation is given special attention. Finally, a mixed norm allowing for both robustness and numerical efficiency is suggested.

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Design and Analysis of an Aircraft Thermal Management System Linked to a Low-Bypass Ratio Turbofan Engine

10.1115/gt2021-58942 ◽

2021 ◽

Author(s):

Robert A. Clark ◽

Mingxuan Shi ◽

Jonathan Gladin ◽

Dimitri Mavris

Keyword(s):

Thermal Management ◽

Management System ◽

Environmental Control ◽

Cooling System ◽

Heat Transfer Fluid ◽

Turbofan Engine ◽

Thermal Management System ◽

Air Stream ◽

The Impact ◽

Bypass Ratio

Abstract The design of an aircraft thermal management system (TMS) that is capable of rejecting heat loads into the bypass stream of a typical low-bypass ratio turbofan engine, or a ram-air stream, is investigated. The TMS consists of an air cycle system (ACS), which is similar to the typical air cycle machines (ACMs) used on current aircraft, both military and commercial. This system turbocharges compressor bleed air and uses heat exchangers in a ram air stream or the engine bypass stream to cool the engine bleed air prior to expanding it to low temperatures suitable for heat rejection. In this study, a simple low-bypass ratio afterburning turbofan engine was modeled in NPSS to provide boundary conditions to the TMS system throughout the flight envelope of a typical military fighter aircraft. The engine was sized to produce sea level static (SLS) thrust roughly equivalent to that of an F-35-class engine. Two different variations of the TMS system, a ram air cooled and a bypass air cooled, were sized to handle a given demanded aircraft heat load, which might include environmental control system (ECS) loads, avionics cooling loads, weapons system loads, or other miscellaneous loads. The architecture and modeling of the TMS is described in detail, and the ability of the sized TMS to reject these demanded aircraft loads throughout several key off-design points was analyzed, along with the impact of ACS engine bleeds on engine thrust and fuel consumption. A comparison is made between the cooling capabilities of the ram-air stream versus the engine bypass stream, along with the benefits and drawbacks of each cooling stream. It is observed that the maximum load dissipation capability of the TMS is tied directly to the amount of engine bleed flow, while the level of bleed flow required is set by the temperature conditions imposed by the aircraft cooling system and the heat transfer fluid used in the ACS thermal transport bus. Furthermore, the higher bypass stream temperatures significantly limit the thermodynamic viability and capability of a TMS designed with bypass air as the ultimate heat sink. The results demonstrate the advantage that adaptive, variable cycle engines (VCEs) may have for future military aircraft designs, as they combine the best features of the two TMS architectures that were studied here.

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ANALISA ENERGI DAN EKSERGI PADA PENGERINGAN TEPUNG TAPIOKA MENGGUNAKAN PENGERING KONTINYU UNGGUN FLUIDISASI GETAR

REAKTOR ◽

10.14710/reaktor.16.1.24-31 ◽

2016 ◽

Vol 16 (1) ◽

pp. 24 ◽

Cited By ~ 2

Author(s):

Suherman Suherman ◽

Rona Trisnaningtyas

Keyword(s):

Energy Efficiency ◽

Fluidized Bed ◽

Exergy Analysis ◽

Cassava Starch ◽

Energy Utilization ◽

Exergetic Efficiency ◽

Energy And Exergy ◽

Vibrated Fluidized Bed ◽

Energy And Exergy Analysis ◽

Utilization Ratio

Energy and exergy analysis of cassava starch drying in continuous vibrated fluidized bed dryer were carried out to assess the performance of the system in terms of energy utilization ratio, energy efficiency, exergy inflow and outflow, exergy loss, and exergetic efficiency. The results showed cassava starch has starch content 87%, degree of whiteness 95%, negative fiber content, sperichal granula with average diameter12.32 μm, orthorhombic crystal structure and crystal size 47.467 nm . Energy utilization and energy utilization ratio increased from 0.08 to 0.20 J/s and 0.35 to 0.4 as the drying temperature increased from 50 to 70 oC. Energy efficiency increased from 13.80 % to 23.31 %, while exergy inflow, outflow, and losses increased from 4.701 to 14.678, 2.277 to 6.344, and 2.424 to 8.334 J/s respectively in the above temperature range. Exergetic efficiency decreased with increase in drying air temperature, while exergetic improvement potential increased with increased drying air temperature. Keywords: Cassava starch, continuous drying, energy and exergy analysis, vibrated fluidized bed Abstrak Analisis energi dan eksergi pengeringan pati tapioka menggunakan pengering kontinu unggun fluidisasi getar, telah dilakukan untuk menilai kinerja sistem dalam bentuk utilisasi energi, efisiensi energi, eksergi masuk dan keluar, eksergi hilang dan efisiensi eksergi. Hasil analisis pati memiliki kandungan starch 87%, tingkat keputihan 95%, kandungan serat negatif, bentuk partikel granular spherical dengan diameter 12,32 μm, struktur kristal orthorhombic dan ukuran kristal sebesar 47,467 nm. Peningkatan suhu pengering dari 50 menjadi 70 0C akan meningkatkan utilisasi energi dan rasio utilisasi energi dari 0,08 menjadi 0,20 J/s dan 0,35 menjadi 0,4. Efisiensi energi meningkat dari 13,80% hingga 23,31%, sedangkan eksergi masuk dan keluar, eksergi hilang meningkat dari 4,701 menjadi 14,678, 2,277 menjadi 6,344, dan 2,424 menjadi 8,334 J/s. Efisiensi eksergi menurun dengan naiknya suhu sedangkan potensi pengembangan eksergi meningkat dengan naiknya suhu. Kata kunci:. Analisis energi dan eksergi, pati tapioka, pengeringan kontinu, unggun fluidisasi getar

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Design and Analysis of an Aircraft Thermal Management System Linked to a Low Bypass Ratio Turbofan Engine

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4052031 ◽

2021 ◽

Author(s):

Robert Clark ◽

Mingxuan Shi ◽

Jonathan Gladin ◽

Dimitri N. Mavris

Keyword(s):

Thermal Management ◽

Management System ◽

Cooling System ◽

Maximum Load ◽

Fighter Aircraft ◽

Turbofan Engine ◽

Cycle System ◽

Thermal Management System ◽

Air Stream ◽

Bypass Ratio

Abstract The design of an aircraft thermal management system (TMS) that is capable of rejecting heat loads into the bypass stream of a typical low-bypass ratio turbofan engine, or a ram-air stream, is investigated. The TMS consists of an air cycle system, similar to the typical air cycle machines used on current aircraft, both military and commercial. This system turbocharges compressor bleed air and uses heat exchangers in a ram air stream, or the engine bypass stream, to cool the engine bleed air prior to expanding it to low temperatures suitable for heat rejection. In this study, a simple low-bypass ratio afterburning turbofan engine was modeled in NPSS to provide boundary conditions to the TMS system throughout the flight envelope of a typical military fighter aircraft. Two variations of the TMS system, a ram air cooled and a bypass air cooled, were sized to handle a given demanded aircraft heat load. The ability of the sized TMS to reject the demanded aircraft load throughout several key off-design points was analyzed. It was observed that the maximum load dissipation capability of the TMS is tied to the amount of engine bleed flow, while the level of bleed flow required is set by the temperature conditions imposed by the aircraft cooling system. Notably, engine bypass stream temperatures significantly limit the thermodynamic viability of a TMS designed with bypass air as the heat sink. The results demonstrate the advantage that variable cycle engines may have for future aircraft designs.

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