scholarly journals ‘The optimization of a jet turbojet engine by PSO and searching algorithms’

2019 ◽  
Author(s):  
Sorush Niknamian
Keyword(s):  
Sea Level ◽  
Exergy Analysis ◽  
Pressure Ratio ◽  
Second Law Of Thermodynamics ◽  
Computer Code ◽  
Exergy Efficiency ◽  
Second Law ◽  
Combustion Chambers ◽  
Software Environment ◽  
Turbojet Engine

The turbojet engine operates on the ideal Brayton cycle (gas turbine) and consists of six main parts: diffusers, compressors, combustion chambers, turbines, afterburners and nozzles. Using computer code writing in MATLAB software environment, exergy analysis on all selected turbojet engine components, exergy analysis on J85-GE-21 turbojet engine for selective height of 10008000 meters above sea level at speeds of 200 m/s and temperatures of 10, 20 and 40 ° C have been provided and then, according to the system functions, the system is optimized based on the PSO method. For the purpose of optimization, variables of Mach number, efficiency of the compressor, turbine, nozzle and compressor pressure ratio are considered in the range of 0.6 to 1.4, 0.8 to 0.95, 0.8 to 0.95 and 7 to 10, respectively. The highest exergy efficiency of different parts of the engine at sea level with an inlet air velocity of 200 m/s corresponds to a diffuser with 73.1%. Then, the nozzle and combustion chamber are respectively 68.6% and 51.5%. The lowest exergy efficiency is related to compressor with 4%. After that, the afterburner is ranked second with 11.6%. Also, the values of entropy produced and the efficiency of the second law before optimization were 1176.99 and 479 w/k respectively and the same values after optimization were 1129 and 51.4 w/k respectively which is identified. After the optimization process, the amount of entropy produced is reduced and the efficiency of the second law of thermodynamics has increased.

scholarly journals The optimization of a jet turbojet engine by PSO and searching algorithms

2020 ◽  
Vol 3 (1) ◽  
pp. 7-11
Author(s):  
Sorush Niknamian
Keyword(s):  
Sea Level ◽  
Exergy Analysis ◽  
Pressure Ratio ◽  
Second Law Of Thermodynamics ◽  
Computer Code ◽  
Exergy Efficiency ◽  
Second Law ◽  
Combustion Chambers ◽  
Software Environment ◽  
Turbojet Engine

The turbojet engine operates on the ideal Brayton cycle (gas turbine) and consists of six main parts: diffusers, compressors, combustion chambers, turbines, afterburners and nozzles. Using computer code writing in MATLAB software environment, exergy analysis on all selected turbojet engine components, exergy analysis on J85-GE-21 turbojet engine for selective height of 1000-8000 meters above sea level at speeds of 200 m/s and temperatures of 10°C, 20°C and 40°C have been provided and then, according to the system functions, the system is optimized based on the PSO method. For the purpose of optimization, variables of Mach number, efficiency of the compressor, turbine, nozzle and compressor pressure ratio are considered in the range of 0.6 to 1.4, 0.8 to 0.95, 0.8 to 0.95 and 7 to 10, respectively. The highest exergy efficiency of different parts of the engine at sea level with an inlet air velocity of 200 m/s corresponds to a diffuser with 73.1%. Then, the nozzle and combustion chamber are respectively 68.6% and 51.5%. The lowest exergy efficiency is related to compressor with 4%. After that, the afterburner is ranked second with 11.6%. Also, the values of entropy produced and the efficiency of the second law before optimization were 1176.99 and 479 w/k respectively and the same values after optimization were 1129 and 51.4 w/k respectively which is identified. After the optimization process, the amount of entropy produced is reduced and the efficiency of the second law of thermodynamics has increased.

Optimization of turbojet engine cycle with dual-purpose PSO algorithm

2019 ◽  
Vol 20 (6) ◽  
pp. 604 ◽  
Author(s):  
M.R. Ahadi Nasab ◽  
M.A. Ehyaei
Keyword(s):  
Entropy Production ◽  
Pressure Ratio ◽  
Second Law Of Thermodynamics ◽  
Pso Algorithm ◽  
Optimization Method ◽  
Exergy Efficiency ◽  
Second Law ◽  
Turbine Efficiency ◽  
Turbojet Engine ◽  
Compressor Pressure Ratio

In this article, the J85-GE-21 turbojet engine for an altitude of 1000–8000 m, with the speed of 200 m/s and at 10, 20, and 40 °C, was provided, and then, based on the objective functions, the above system was optimized using particle swarm optimization method. For the purpose of optimization, the Mach number, compressor efficiency, turbine efficiency, nozzle efficiency, and compressor pressure ratio were assumed to be in the range of 0.6–1.4, 0.8–0.95, 0.8–0.95, 0.8–0.95, and 7–10, respectively. The highest exergy efficiency of 73.1% for different components of the engine at sea level and speed of 200 m/s belonged to the diffuser. Second and third to it were nozzle and combustion chamber with 68.6 and 51.5%, respectively. The lowest exergy efficiency of 4% belonged to the compressor, and the second to it was the afterburner with 11.6%. Also, the values of entropy production and efficiency of the second law of thermodynamics were 1176.99 and 479 K/W, respectively, prior to optimization, which were respectively changed to 1129 and 51.4 K/W postoptimization. Obviously, the entropy production is reduced, while the efficiency of the second law of thermodynamics is increased.

Exergy Analysis of Transcritical Regenerative Organic Rankine Cycle Using Isobutane

2013 ◽  
Vol 442 ◽  
pp. 183-186
Author(s):  
Kyoung Hoon Kim
Keyword(s):  
Exergy Analysis ◽  
Organic Rankine Cycle ◽  
Internal Heat ◽  
Second Law Of Thermodynamics ◽  
Rankine Cycle ◽  
Exergy Efficiency ◽  
Second Law ◽  
Source Temperature ◽  
Internal Heat Exchanger ◽  
Maximum Value

Exergy analysis is performed for transcritical Organic Rankine Cycle (ORC) with internal heat exchanger based on the second law of thermodynamics. Effects of source temperature as well as turbine inlet pressure (TIP) are investigated on the exergy destructions (or anergies) of the system as well as exergy efficiency. Results show that irreversibility of the system decreases with increasing TIP or decreasing source temperature. Exergy efficiency decreases with increasing source temperature; however has a maximum value with respect to TIP.

scholarly journals ANALISIS EKSERGI PENGERINGAN IRISAN TEMULAWAK

2016 ◽  
Vol 36 (01) ◽  
pp. 96
Author(s):  
Lamhot Parulian Manalu ◽  
Armansyah Halomoan Tambunan
Keyword(s):  
Exergy Analysis ◽  
Second Law Of Thermodynamics ◽  
Exergy Efficiency ◽  
Energy Utilization ◽  
Second Law ◽  
Process Conditions ◽  
Drying Process ◽  
Conservation Of Energy ◽  
Thin Layer Drying ◽  
Curcuma Xanthorrhiza

Java turmeric (Curcuma xanthorrhiza Roxb.) is a medicinal plant used as raw material for making herbal medicine, its rhizome cut into slices and dried so called simplicia. Curcuma has a harvest moisture content is high enough to need a great energy for drying. Generally, the theory used to analyze the energy efficiency is the first law of thermodynamics that describes the principle of conservation of energy. However, this theory has limitations in measuring the loss of energy quality. To determine whether the energy used in the drying process has been used optimally in terms of quality, the second law of thermodynamics -known as exergy analysis- is used. The purpose of this study is to determine the efficiency of the thin layer drying of curcuma slices with exergy analysis. The results show that the process conditions affect the energy utilization ratio and exergy efficiency of drying. Exergy analysis method based on the second law of thermodynamics has been used to determine the amount of exergy destroyed so that the efficiency of the drying process can be determined more accurately. Exergy efficiency varies between 96.5%-100% for temperatures of 50 °C to 70 °C at 40% RH and 82.3% - 100% for 20% to 40% RH at 50 °C.Keywords: Drying, energy, exergy efficiency, curcuma slices ABSTRAKTemulawak (Curcuma xanthorrhiza Roxb.) merupakan tanaman obat yang simplisianya digunakan sebagai bahan baku pembuatan jamu atau obat tradisional. Pengeringan merupakan proses utama dalam memproduksi simplisia. Untuk menganalisis efisiensi energi suatu proses pengeringan umumnya digunakan hukum termodinamika pertama yang menjelaskan tentang prinsip kekekalan energi. Akan tetapi teori ini mempunyai keterbatasan dalam mengukur penurunan kualitas energi. Untuk mengetahui apakah energi yang digunakan pada proses pengeringan sudah digunakan secara optimal dari sisi kualitas, digunakan hukum termodinamika kedua atau yang dikenal dengan analisis eksergi. Tujuan penelitian ini adalah menentukan efisiensi proses pengeringan lapisan tipis irisan temulawak dengan metode analisis energi dan eksergi. Dalam studi ini, metode analisis energi dan eksergi berdasarkan hukum termodinamika pertama dan kedua telah digunakan untuk menghitung rasio penggunaan energi dan besaran eksergi yang musnah (exergy loss). sehingga efisiensi proses pengeringan irisan temulawak dapat ditentukan secara akurat. Hasil penelitian menunjukkan bahwa kondisi proses pengeringan mempengaruhi rasio penggunaan energi dan efisiensi eksergi pengeringan. Semakin tinggi suhu dan RH pengeringan maka rasio penggunaan energi semakin rendah dan efisiensi eksergi semakin tinggi. Efisiensi eksergi pengeringan temulawak bervariasi antara 96,5%-100% untuk selang suhu 50 oC hingga 70 oC pada RH 40% serta 82,3% - 100% untuk selang RH 20% hingga 40% pada suhu 50 oC. Kata kunci: Pengeringan, energi, efisiensi eksergi, temulawak

On-design exergy analysis of a combustor for a turbojet engine: a parametric study

2017 ◽  
Vol 89 (5) ◽  
pp. 719-724 ◽  
Author(s):  
Ahmet Topal ◽  
Onder Turan
Keyword(s):  
Exergy Analysis ◽  
Pressure Ratio ◽  
Negative Influence ◽  
Exergy Efficiency ◽  
Inlet Pressure ◽  
Practical Implementation ◽  
System Effect ◽  
Content Type ◽  
Turbojet Engine ◽  
Exit Temperature

Purpose The purpose of this study is to perform an exergy analysis of a turbojet engine combustor at different cycle parameters. Design/methodology/approach Base cycle parameters have been defined for the engine, and then differentiation of the combustor exergy efficiencies and destruction rates have been evaluated by changing overall pressure ratio, combustor exit temperature and combustor pressure ratio. Findings For the basic engine cycle, combustor unit is found to have lowest exergy efficiency as 62.3 for the sea level static condition. Compressor turbine exhaust and whole engine exergy efficiencies have been calculated as 88.7, 96.5, 68.2 and 69.4, respectively. Practical implications Because of the biggest exergy, destruction is seen mainly in combustion system; effect of the combustor inlet pressure (related to the compressor design technology), pressure drop and exit temperature on the exergy efficiencies have been analyzed and combustor second law efficiency have been evaluated. Social implications The investigation’s purposes are highly connected with social wellness and targeted at sustainable development of the society. Practical implementation of the obtained scientific results is directed on the improving of combustor for a turbojet engines and decreasing negative influence on the environment. Originality/value As a result of this paper, the following are the contribution of this paper in the field of gas turbine exergy subjects: Combustor has been found as the most critical component in respect of the exergy efficiency. Therefore, the effect of the combustor main cycle parameters such as inlet pressure, combustor pressure ratio and exit temperature have been analyzed.

scholarly journals Exergetic analysis of an aircraft turbojet engine with an afterburner

2013 ◽  
Vol 17 (4) ◽  
pp. 1181-1194 ◽  
Author(s):  
M.A. Ehyaei ◽  
A. Anjiridezfuli ◽  
M.A. Rosen
Keyword(s):  
Sea Level ◽  
Exergy Analysis ◽  
Exergy Efficiency ◽  
Brayton Cycle ◽  
Simulation Data ◽  
Turbojet Engine ◽  
Air Speed ◽  
Exergetic Analysis ◽  
Engine Components ◽  
Aircraft Data

An exergy analysis is reported of a J85-GE-21 turbojet engine and its components for two altitudes: sea level and 11,000 meters. The turbojet engine with afterburning operates on the Brayton cycle and includes six main parts: diffuser, compressor, combustion chamber, turbine, afterburner and nozzle. Aircraft data are utilized in the analysis with simulation data. The highest component exergy efficiency at sea level is observed to be for the compressor, at 96.7%, followed by the nozzle and turbine with exergy efficiencies of 93.7 and 92.3%, respectively. At both considered heights, reducing of engine intake air speed leads to a reduction in the exergy efficiencies of all engine components and overall engine. The exergy efficiency of the turbojet engine is found to decrease by 0.45% for every 1?C increase in inlet air temperature.

The Impact of Reference Environment Selection on the Exergy Efficiencies of Aerospace Engines

1999 ◽  
Author(s):  
Jason Etele ◽  
Marc A. Rosen
Keyword(s):  
Sea Level ◽  
Exergy Analysis ◽  
Operating Environment ◽  
A Value ◽  
Turbojet Engine ◽  
Reference Environment ◽  
The Impact

Abstract An exergy analysis is applied to a turbojet engine over a range of flight altitudes ranging from sea level to 15,000 m (∼50,000 ft), to examine the effects of using different reference-environment models. The results of this analysis using a variable reference environment (equal to the operating environment at all times) are compared to the results obtained using two constant reference environments (sea level and 15,000 m). The actual rational efficiency of the turbojet decreases with increasing altitude, ranging from a value of 16.9% at sea level to 15.3% at 15,000 m. In the most extreme cases considered, the rational efficiency value calculated using a constant reference environment varies by approximately 2% from the variable reference environment value.

scholarly journals From Entropy Generation to Exergy Efficiency at Varying Reference Environment Temperature: Case Study of an Air Handling Unit

Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 361 ◽  
Author(s):  
Giedrė Streckienė ◽  
Vytautas Martinaitis ◽  
Juozas Bielskus
Keyword(s):  
Heat Pump ◽  
Entropy Generation ◽  
Energy Demand ◽  
Dynamic Modelling ◽  
Second Law Of Thermodynamics ◽  
Exergy Efficiency ◽  
Second Law ◽  
Air Handling Unit ◽  
Individual Character ◽  
Environment Temperature

The continuous energy transformation processes in heating, ventilation, and air conditioning systems of buildings are responsible for 36% of global final energy consumption. Tighter thermal insulation requirements for buildings have significantly reduced heat transfer losses. Unfortunately, this has little effect on energy demand for ventilation. On the basis of the First and the Second Law of Thermodynamics, the concepts of entropy and exergy are applied to the analysis of ventilation air handling unit (AHU) with a heat pump, in this paper. This study aims to develop a consistent approach for this purpose, taking into account the variations of reference temperature and temperatures of working fluids. An analytical investigation on entropy generation and exergy analysis are used, when exergy is determined by calculating coenthalpies and evaluating exergy flows and their directions. The results show that each component of the AHU has its individual character of generated entropy, destroyed exergy, and exergy efficiency variation. However, the evaporator of the heat pump and fans have unabated quantities of exergy destruction. The exergy efficiency of AHU decreases from 45–55% to 12–15% when outdoor air temperature is within the range of −30 to +10 °C, respectively. This helps to determine the conditions and components of improving the exergy efficiency of the AHU at variable real-world local climate conditions. The presented methodological approach could be used in the dynamic modelling software and contribute to a wider application of the Second Law of Thermodynamics in practice.

Exergy Analysis of a Turbojet Engine Over a Complete Flight Cycle

2001 ◽  
Author(s):  
Marc A. Rosen
Keyword(s):  
Sea Level ◽  
Exergy Analysis ◽  
Operating Environment ◽  
Turbojet Engine ◽  
Reference Environment ◽  
Selection Of

Abstract Exergy analysis is used to evaluate the efficiency of a turbojet engine over an entire flight (including climb, cruise and descent), and to assess the sensitivity of these results to the selection of the reference environment. This study is an extension of previous work where the accuracy of an exergy analysis of a turbojet engine is evaluated for different reference environments on an instantaneous basis. The present work evaluates cumulative engine efficiencies. The results show that the use of a constant reference environment set at cruise altitude conditions yields cumulative exergy efficiencies that are within 0.01% of those found using a variable reference environment (equal to the operating environment conditions at all times) over a 3,500 km flight. This result is in contrast to the use of a constant sea-level reference environment where such are 3.7%. This significant cumulative efficiency difference with the choice of reference environment is not observed when using an instantaneous exergy analysis. Care must be exercised when using a constant reference environment, as for both constant sea-level and cruise-altitude reference environments cumulative rational efficiencies increase over the majority of the flight, whereas for a continuously varying reference environment these efficiencies decrease.

scholarly journals Exergy Analysis of Integrated Gas-Steam Cycle

1994 ◽  
Author(s):  
Onkar Singh ◽  
R. Yadav
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Exergy Analysis ◽  
Waste Heat ◽  
Second Law Of Thermodynamics ◽  
Heat Recovery Boiler ◽  
Second Law ◽  
Operating Parameters ◽  
Insight Into ◽  
Steam Cycle

The thermodynamic analysis of integrated gas/steam cycle has been carried out on the basis of second law of thermodynamics. The exergy analysis provides a viable understanding of the influence of various parameters on the distribution of losses in the constituent components of the cycle. The paper also provides the insight into the influence of changing operating parameters on the performance of the waste heat recovery boiler, which in turn questions the viability of the integrated gas/steam cycle.

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