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Article
Publication date: 1 November 2019

P. Gunasekar, S. Manigandan, Venkatesh S., R. Gokulnath, Rakesh Vimal and P. Boomadevi

The depletion of fossil fuel and emissions of harmful gases forced the pioneers in search of alternate energy source. The purpose of this study is to present an effective use of…

877

Abstract

Purpose

The depletion of fossil fuel and emissions of harmful gases forced the pioneers in search of alternate energy source. The purpose of this study is to present an effective use of hydrogen fuel for turbojet engines based on its exergetic performance.

Design/methodology/approach

This study was performed to measure the assessment of exergetic data of turbojet engines. Initially, the test was carried out on the Jet A-1 fuel. Then, a series of similar tests were carried out on turbojet engines with hydrogen fuel to measure their performance results. Finally, the exergetic values of both were compared with each other.

Findings

The introduction of hydrogen fuel reduced the exergy efficiency, and a 10 per cent reduction was observed in exergy efficiency. Simultaneously, the waste exergy rate increased by 9 per cent. However, because of the high specific fuel exergy, hydrogen fuel was better than Jet A-1 fuel. Note that parameters such as environmental effect factor and ecological effect witnessed an increase in their index owing to the addition of hydrogen.

Practical implications

Introduction of alternative blends is necessary for achieving lower emission of gases such as CO, NOx and CO2 from gas turbine engines without compromising on performance. The Jet A fuels were replaced by blends to obtain better emission characteristics.

Originality/value

The use of hydrogen in turbojet engines showed an adverse effect on exergetic performance. However, it was very impressive to see a 200 per cent reduction in emissions. From the comparison of exergy efficiency results of inlet, combustion and nozzle, it is evident that the combustion chamber has the largest values of exergy ratio, waste exergy ratio, cost flow, ecological factor, environmental factor and fuel ratio owing to irreversibility in the combustion process.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 2
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 11 November 2020

Booma Devi, Venkatesh S., Rakesh Vimal and Praveenkumar T.R.

This paper aims to investigate the effect of additives in Jet-A fuel blends, especially on performance, combustion and emission characteristics.

245

Abstract

Purpose

This paper aims to investigate the effect of additives in Jet-A fuel blends, especially on performance, combustion and emission characteristics.

Design/methodology/approach

Jet-A fuel was formed by using Kay’s and Gruenberg–Nissan mixing rules by adding additive glycerol with TiO2. While measuring the combustion performance, the amount of oxygen content present in fuel and atomization are the key factors to consider. As such, the Jet-A fuel was created by adding additives at different proportion. A small gas turbine engine was used for conducting tests. All tests were carried out at different load conditions for all the fuel blends such as neat Jet-A fuel, G10T (glycerol 10% with 50 ppm TiO2 and Jet-A 90%), G20T (glycerol 10% with 50 ppm TiO2 and Jet-A 90%) and G30T (glycerol 10% with 50 ppm TiO2 and Jet-A 90%).

Findings

From tests, the G20T and G10T produced better results than other blends. The thermal efficiency of the blends of G20T and G10T are 22% and 14% higher than neat Jet-A fuel. Further, the improved static thrust with less fuel consumption was noticed in G20T fuel blend.

Originality/value

The G20T blends showed better performance because of the increased oxygenated compounds in the fuel blends. Moreover, the emission rate of environmentally harmful gases such as NOx, CO and HC was lower than the neat Jet-A fuel. From the results, it is clear that the rate of exergy destruction is more in the combustion chamber than the other components of fuel.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 3
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 30 December 2020

P. Gunasekar, S. Manigandan and Praveen Kumar T.R.

The rise in demand and high utilization of fuel causes severe environmental threat for the nations on the globe. Rapid burning potential of hydrogen produces enormous amount of…

1361

Abstract

Purpose

The rise in demand and high utilization of fuel causes severe environmental threat for the nations on the globe. Rapid burning potential of hydrogen produces enormous amount of thrust, and it is mainly owing to wide flame range and less onset of ignition.

Design/methodology/approach

The significant contribution of hydrogen as fuel has been explored by several researchers around the globe recently to use in aviation sector owing to its eco-friendly nature. Hydrogen is a safe and clean fuel, and it can be generated from several sources. The effects of addition on hydrogen on gas turbine on combustion characteristics and emission concentration level on atmosphere have been reviewed in this paper.

Findings

Incorporation of hydrogen is effective reducing nitrous oxide emission, high calorific value and flame less combustion. Addition of hydrogen to higher proportions enhances the combustion performance, minimizing the setbacks of conventional fuel and meets the specified standards on emission.

Originality/value

From the literature review, the comparative study on hydrogen with other fuel is explained. This paper concludes that addition of hydrogen in fuel enhances the performance of combustion on gas turbine engine along with significant reduction in emission levels.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 3
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 18 October 2018

S. Manigandan and Vijayaraja K.

The purpose of this paper is to present the results of mixing promotion and screech frequency of controlled elliptical supersonic jet.

173

Abstract

Purpose

The purpose of this paper is to present the results of mixing promotion and screech frequency of controlled elliptical supersonic jet.

Design/methodology/approach

Flow field characteristics of low-aspect-ratio elliptical jets are examined at over-expanded, under-expanded and correctly expanded conditions. The tabs are placed at elliptical jet exit along the major and minor axes.

Findings

The results show that the mixing done by the minor axis is superior to the tabs along major axis. At all pressure ratios, the content of jet noise and the frequency are high for the tabs along the major axis because of increase in the amplitude of screech frequency. Further the tabs along minor axis show a dominance of large-scale vertical structures. In under-expanded conditions, the shock cell shows the rapid change because of the presence of tabs. The tabs along minor axis are making the shock weaker, hence no evidence of axis switching.

Practical implications

To achieve the greater performance of jet, the authors need to reduce the potential core length of the issuing jet. This can be achieved by implementing different types of tabs at the exit of the nozzle.

Originality/value

The present paper represents the flow of controlled jet using inverted triangular tabs. By achieving the controlled jet flow, the performance of propulsion systems can be improved. This can be used in systems such as combustion chamber, missile’s noise reduction and thrust vector control.

Details

Aircraft Engineering and Aerospace Technology, vol. 90 no. 9
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 23 October 2020

Anderson A., Karthikeyan A., Ramesh Kumar C., Ramachandran S. and Praveenkumar T.R.

The purpose of this study is to predict the performance and emission characteristics of micro gas turbine engines powered by alternate fuels. The micro gas turbine engine…

885

Abstract

Purpose

The purpose of this study is to predict the performance and emission characteristics of micro gas turbine engines powered by alternate fuels. The micro gas turbine engine performance, combustion and emission characteristics are analyzed for the jet fuel with different additives.

Design/methodology/approach

The experimental investigation was carried out with Jet A-1 fuel on the gas turbine engines at different load conditions. The primary blends of the Jet A-1 fuels are from canola and solid waste pyrolysis oil. Then the ultrasonication of highly concentrated multiwall carbon nanotubes is carried with the primary blends of canola (Jet-A fuel 70%, canola 20% and 10% ethanol) and P20E (Jet-A 70% fuel, 20% PO and 10% ethanol).

Findings

The consumption of the fuel is appreciable with the blends at a very high static thrust. The 39% reduction in thrust specific fuel consumption associated with a 32% enhance in static thrust with P20E blend among different fuel blends. Moreover, due to the increase in ethanol concentration in the blends PO20E and C20E lead to a 22% rise in thermal efficiency and a 9% increase in higher oxygen content is observed.

Practical implications

The gas turbine engine emits very low emission of gases such as CO, CO2 and NOx by using the fuel blends, which typically reduces the fossil fuel usage limits with reduced pollutants.

Originality/value

The emission of the gas turbine engines is further optimized with the addition of hydrogen in Jet-A fuel. That is leading to high specific fuel exergy and owing to the lower carbon content in the hydrogen fuel when compared with that of the fossil fuels used in gas turbine engines. Therefore, the usage of hydrogen with nanofluids was so promising based on the results obtained for replacing fossil fuels.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 3
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 16 January 2025

Nithya Subramani, Sangeetha M. and Gowtham G.

The purpose of the study is to find the effect of convergent and divergent section length on the exit flow characteristics. Converging-diverging (CD) nozzle design can be…

13

Abstract

Purpose

The purpose of the study is to find the effect of convergent and divergent section length on the exit flow characteristics. Converging-diverging (CD) nozzle design can be difficult because of the necessity for precise geometry and an understanding of compressible fluid flow dynamics. To obtain the ideal supersonic speeds, it is challenging to make sure that the flow chokes at the throat, where the Mach number approaches one and then expands appropriately in the diverging region. The design needs to take into consideration things like the relationship between the area and Mach number, the impact of various pressure ratios and the flow’s isentropic interactions.

Design/methodology/approach

An ideal thrust production is achieved through the effective acceleration of exhaust gases through proper nozzle design. This paper numerically investigates impact of convergent, divergent length and nozzle pressure ratio on the exit Mach Number of CD nozzle supersonic jet. Exit Mach Number 1.6 convergent-divergent nozzle was used. In total, five cases were taken as the length of the both the convergent-divergent sections were modified with 50% of increment and decrement in its base length. At four different NPR, the analysis was carried out in over-expanded, correctly expanded and under-expanded conditions. The NPR used were 2, 3.2, 4 and 5.

Findings

From the results, it is found that the convergent length linearly affects the exit Mach number, while the divergent length variation is not in order. Both the decreased and increased divergent length reduce the supersonic jet exit Mach number. The subsonic region is not majorly affected by the length. There is no rapid change in the flow properties whether the length is reduced or increased. Maximum of 2% to 3% variation is only noticed. On the contrary, a small change in supersonic region or divergent section makes major modification in the flow.

Originality/value

To achieve the desired Mach number, not only the area of the nozzle but also the length affects it. In terms of divergent angle and area ratio, only most of the studies on nozzle have been focused. This study aims to find the impact of convergent length and divergent length on the exit Mach number. This could be used in a wide range of applications, including laser cutting, thermal spraying, gas turbines for power generation, rocket and jet engines, supersonic wind tunnels and turbo chargers in automotive engineering, because of their capacity to accelerate fluids to supersonic speeds.

Details

Aircraft Engineering and Aerospace Technology, vol. 97 no. 2
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 7 June 2021

Ismail Hakki Hakkı Akçay, Habib Gürbüz, Hüsameddin Akçay and Mustafa Aldemir

This study seeks the effect on static thrust, thrust specific energy consumption (TSEC) and exhaust emissions of euro diesel-hydrogen dual-fuel combustion in a small turbojet…

419

Abstract

Purpose

This study seeks the effect on static thrust, thrust specific energy consumption (TSEC) and exhaust emissions of euro diesel-hydrogen dual-fuel combustion in a small turbojet engine.

Design/methodology/approach

Experimental studies are performed in a JetCat P80-SE type small turbojet engine. Euro diesel and hydrogen is fed through two different inlets in a common rail distributing fuel to the nozzles. Euro diesel fuel is fed by a liquid fuel pump to the engine, while hydrogen is fed by a fuel-line with a pressure of 5 bars from a gas cylinder with a pressure of approximately 200 bars.

Findings

At different engine speeds, it is found that there is a decrease at the TSEC between a range of 1% and 4.8% by different hydrogen energy fractions (HEF).

Research limitations/implications

The amount of hydrogen is adjusted corresponding to a range of 0–20% of the total heat energy of the euro diesel and hydrogen fuels. The small turbojet engine is operated between a range of 35,000 and 95,000 rpm engine speeds.

Practical implications

On the other hand, remarkable improvements in exhaust emissions (i.e. CO, CO2, HC and NOx) are observed with HEFs.

Originality/value

This is through providing improvements in performance and exhaust emissions using hydrogen as an alternative to conventional jet fuel in gas turbine engines.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 4
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 9 July 2024

Manigandan Sekar, Vijayaraja Kengaiah, Praveenkumar T.R. and Gunasekar P.

The purpose of this study is to investigate the effect of coaxial swirlers on acoustic emission and reduction of potential core length in jet engines.

48

Abstract

Purpose

The purpose of this study is to investigate the effect of coaxial swirlers on acoustic emission and reduction of potential core length in jet engines.

Design/methodology/approach

The swirlers are introduced in the form of curved vanes with angles varied from 0° to 130°, corresponding to swirl numbers of 0–1.5. These swirlers are fixed in the annular chamber and tested at different nozzle pressure ratios of 2, 4 and 6.

Findings

The study finds that transonic tones exist for the nonswirl jet, creating an unfavorable effect. However, these screech tones are eliminated by introducing a swirl jet at the nozzle exit. Weak swirl shows a greater reduction in noise than strong swirl at subsonic conditions. In addition, the introduction of swirl jets at all pressure ratios significantly reduces jet noise and core length in supersonic conditions, mitigating the noise created by shockwaves and leading to screech tone-free jet mixing.

Originality/value

The paper provides valuable insights into the use of coaxial swirlers for noise reduction and core length reduction in jet engines, particularly in supersonic conditions.

Details

Aircraft Engineering and Aerospace Technology, vol. 96 no. 7
Type: Research Article
ISSN: 1748-8842

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Case study
Publication date: 12 November 2024

Padmalini Singh, Tamizharasi D. and Purushottam Bung

After completion of the case study, students will be able to discuss the characteristics of sustainable enterprises driving the innovation; analyze the concept of waste to wealth…

Abstract

Learning outcomes

After completion of the case study, students will be able to discuss the characteristics of sustainable enterprises driving the innovation; analyze the concept of waste to wealth, along with its associated benefits and challenges; provide an example of a sustainable start-up that operates conventionally and is attempting to increase production capacity through automation; and describe the strategies for scaling up the business.

Case overview/synopsis

Mr Manigandan Kumarappan’s goal was to provide the world with alternatives to plastic and other nonbiodegradable articles used in homes, offices, hotels and other places which compelled him to leave his corporate life behind and become an entrepreneur. His knowledge, expertise and creativity made him work toward providing a sustainable solution to the plastic-free world which made him create leafy straws for the world. His start-up Evalogia made 10,000 straws a day, mostly with manual production and machine-assisted in part of the processes. Evalogia got orders from all over the world after the ban on plastic from many countries. However, Evalogia was unable to meet the demand, as the manufacturing process mostly depended on manual production at present. Hence, the company planned to scale up its production capacity from 10,000 straws per day to 100,000 straws to meet the demand through automation or by increasing the production units to meet the growing demand from domestic and international markets. Kumarappan wondered if increasing the number of manufacturing facilities would make it harder to hire new staff, manage existing ones, train them and provide overall supervision; if these tasks were not completed well, the product’s quality and, subsequently, its demand, might suffer. The automation process required huge investment, time and a great deal of skepticism for its success. Kumarappan was stuck over whether to add more production units or automate the process to increase production.

Complexity academic level

This case study is suitable for graduate students.

Supplementary materials

Teaching notes are available for educators only.

Subject code

CSS 3: Entrepreneurship.

Details

Emerald Emerging Markets Case Studies, vol. 14 no. 4
Type: Case Study
ISSN: 2045-0621

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Article
Publication date: 8 February 2021

Pradeep Uttam Gaikwad, Senthil Gnanamani and Nithya Subramani

The purpose of this paper is to find the pressure and the knocking phenomena. To get the pressure values, the butterworth bandpass filter was used and the potential of knocking…

637

Abstract

Purpose

The purpose of this paper is to find the pressure and the knocking phenomena. To get the pressure values, the butterworth bandpass filter was used and the potential of knocking was found by using peak-to-peak pressure values and also the species concentration. Cooled exhaust gas recirculation was the method used to minimize the knocking occurrence in the engine. Moreover, the effect of premixed methanol and start of engine (SOI) on knocking were also determined.

Design/methodology/approach

This paper deals with the compression ignition engine to investigate the unfavorable knocking behavior. The tests were carried out with the 3D model of engine fueled with waste cooking oil blended with TiO2. A number of tests were taken to find the pressure variation and the species concentration at eight different locations in the computational model.

Findings

In doing the tests, the positive intended outcome was achieved. From results, it is clear that the SOI and premixed methanol mitigated the knocking process.

Originality/value

The species concentration and pressure in the form of filtered signal were proved to be the ideal methods for evaluating the knocking event in the engine.

Details

Aircraft Engineering and Aerospace Technology, vol. 94 no. 4
Type: Research Article
ISSN: 1748-8842

Keywords

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