scholarly journals Fast drift effects in the averaging of a filtration combustion system: A periodic homogenization approach

2018 ◽  
Vol 77 (1) ◽  
pp. 71-104 ◽  
Author(s):  
Ekeoma R. Ijioma ◽  
Adrian Muntean
Keyword(s):  
Filtration Combustion ◽  
Combustion System ◽  
Periodic Homogenization ◽  
System A ◽  
Homogenization Approach ◽  
Fast Drift

A Contribution to the Theory of the Development and Stability of Detonation in Gases

1952 ◽  
Vol 19 (1) ◽  
pp. 63-71
Author(s):  
A. K. Oppenheim
Keyword(s):  
Detonation Wave ◽  
Cross Section ◽  
Combustion Zone ◽  
Gas Mixture ◽  
Constant Cross Section ◽  
Combustion System ◽  
Adequate Explanation ◽  
System A

Abstract The development of detonation of an explosive gas mixture contained in a constant-cross-section duct is analyzed on the basis of a unidimensional, gasdynamic treatment of a double-discontinuity combustion system. A steady and an unsteady system are considered, and it is shown that the latter yields an adequate explanation of the effect of coalition of the two discontinuities on the establishment and subsequent stability of the detonation wave. The locus of states behind the detonating combustion zone during the development of the process is determined and analyzed.

A Lean Burn Low Emissions Gas Engine for Co-Generation

1996 ◽  
Vol 210 (3) ◽  
pp. 203-211 ◽  
Author(s):  
K J S Mendis ◽  
C R Stone ◽  
N Ladommatos ◽  
M Daragheh
Keyword(s):  
Combustion Model ◽  
Hydrocarbon Emissions ◽  
Combustion System ◽  
High Compression Ratio ◽  
Specific Mass ◽  
Lean Burn ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
System A ◽  
Brake Mean Effective Pressure

This paper presents the rationale behind a fast burn high compression ratio (FBHCR) combustion system intended for use in a lean burn natural gas engine. Comparisons are made between the FBHCR combustion system, predictions made by a two-zone combustion model and measurements from the original combustion system, for the brake efficiency, brake mean effective pressure and the brake specific NOx emissions. Experimental measurements of the unburnt hydrocarbon emissions, the burn duration and the cycle-by-cycle variations in combustion are also discussed from the two combustion systems. The results show how the conflicting aims of low emissions and low fuel consumption can be satisfied by using a lean burn combustion system. A comparison is also made between the following ways of expressing the exhaust emissions: volumetric, brake specific, mass per megajoule of fuel and gravimetric referenced to a specified oxygen level.

scholarly journals Field Experience of the Sequential Combustion System for the GT24/GT26 Gas Turbine Family

1998 ◽  
Author(s):  
Franz Joos ◽  
Philipp Brunner ◽  
Marcel Stalder ◽  
Stefan Tschirren
Keyword(s):  
Gas Turbine ◽  
Research Work ◽  
Basic Research ◽  
Test Facility ◽  
Test Results ◽  
Combustion System ◽  
System A ◽  
Commercial Operation ◽  
Near Future

The first units of the Sequential Combustion System gas turbine family are in commercial operation. The first gas turbine GT24 (60Hz, 165MW-class) started the commercial operation, while the first GT26 (50Hz, 265MW-class) demonstrates its performance at the GT test facility. More engines are presently in the commissioning phase or will be in the near future. These turbines are designed to offer increased output at high GT efficiency. To acheive this, the sequential combustion system, a reheat process with two combustors, has been developed. Whereas the first combustor is based on the proven EV-combustor technology, extensive research and development efforts have been carried out in developing the lean premixed self-igniting second combustor (SEV). This paper is a follow-up of the ASME paper 96-GT-315, which described the basic research work concerning the lean premixing SEV-burners with self-ignition. The present paper reports the experience gained during commissioning of the first engines. The performance of the two combustors, as well as the measured emissions, are discussed and compared with the expected values and rig test results. Finally, the potential of the sequential combustion system to reach low NOx levels is demonstrated by unveiling the results of the extensive testing program during the commissioning phase.

scholarly journals Inovasi Sistem Pemisah Logam dalam Mendukung Pembangkit Listrik Tenaga Sampah (PLT Sampah)

2019 ◽  
Vol 20 (2) ◽  
pp. 205
Author(s):  
Iin Parlina ◽  
Wiharja Wiharja ◽  
Iif Miftahul Ihsan
Keyword(s):  
Pilot Plant ◽  
Waste To Energy ◽  
Added Value ◽  
Combustion System ◽  
Separation System ◽  
Plant System ◽  
System A ◽  
Metal Separation ◽  
Magnetic Cores ◽  
Large Project

ABSTRACTIn the Waste to Energy (WtE) Pilot Plant system, the garbage feed has high diverse content including various type of metal. A metal separation system plays an important role during waste pretreatment process before the garbage entering the incinerator. This system is aimed to prevent performance degradation of the combustion system and to gain added value of the reuse metals in the waste. The WtE Pilot Plant in Bantargebang, constructed in 2018, is a large project and is expected to contribute significantly in overcoming waste problems in Indonesia. The performance of the WtE pilot plant system increases significantly if supported by a metal separator system integrated to the existing pretreatment system. This paper evaluates new design of metal separation system from the waste inputs. In general, metal separator system was designed as a permanent unit with a stand alone or integrated electromagnetic lifting. In this paper, the metal separator system was designed by using a combination of permanent ferrite and neodymium magnetic cores to create a combined force able to pull scraps mixed in waste at a considerable distance and was easily removed and collected. To optimize the system, a metal separator system was attached to a crane system installed in a double cabin car. Thus, the flexibility of this system was increasingly high. Tests results showed that the metal separator system with a combination of ferrite and neodymium was able to pull metals in the waste from a distance up to 20 cm despite of blocking by non-magnetic wastes, and able to attract almost 100% of the exisiting metals. Key words: WtE, metal separator, ferrite, neodymium, waste, mobile systemABSTRAKPada sistem Pembangkit Listrik Tenaga Sampah (PLT Sampah), di mana umpan sampah memiliki keberagaman yang tinggi, termasuk keberadaan logam di dalamnya, sistem pemisahan logam sebagai tahapan pretreatment sampah sebelum masuk ke dalam sistem insinerator akan memegang peranan yang cukup penting. Sistem ini bertujuan untuk mencegah penurunan kinerja sistem pembakaran serta untuk meningkatkan nilai dari penggunaan ulang logam yang tercampur ke dalam sampah. Pembangunan Pilot PLT Sampah di Bantargebang yang dimulai pada tahun 2018 merupakan suatu proyek besar dan diharapkan dapat memberikan kontribusi yang signifikan dalam mengatasi permasalahan sampah di Indonesia. Kinerja sistem PLT Sampah ini akan lebih baik jika didukung oleh sistem pemisah logam yang dapat diintegrasikan dengan sistem pretreatment yang telah ada. Inovasi sistem ini dirancang untuk melakukan pemilahan terhadap input sampah yang masuk ke dalam sistem PLT Sampah yang berupa logam sehingga sampah logam tidak turut terbakar. Pada umumnya, pemisah logam dibuat sebagai unit permanen dengan menggunakan magnet pengangkat berupa elektromagnet yang berdiri sendiri atau bisa terintegrasi. Namun pada sistem ini, sistem pemisah logam dirancang dengan menggunakan magnet permanen yang menggabungkan inti magnet ferrite dan neodymium sehingga akan menciptakan kombinasi antara sistem yang dapat menarik scrap yang tercampur dalam sampah pada jarak yang cukup jauh namun bisa dilepaskan dengan mudah untuk dikumpulkan. Untuk membuat sistem ini bekerja optimal, sistem pemisah logam dibuat secara mobil dengan memadukannya dengan sistem derek yang terpasang pada sistem mobil kabin ganda. Dengan demikian, fleksibilitas sistem ini menjadi semakin tinggi. Uji yang telah dilakukan menunjukkan sistem pemisah logam dengan kombinasi ferrite- neodymium ini dapat menarik logam yang tercampur pada sampah hingga jarak 20 cm meskipun terhalang sampah yang lain (non-magnet), dan menarik hampir 100% dari logam yang tersedia.Kata kunci : PLT Sampah, pemisah logam, ferrite, neodymium, sampah, sistem mobil

The Kinetic Model Including Singlet Oxygen and Ozone in Hydrogen-Air Mixture

2013 ◽  
Vol 772 ◽  
pp. 239-245
Author(s):  
Yan Nan Chang ◽  
Chang Hui Wang ◽  
Tong Guang Cheng
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Singlet Oxygen ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Flame Temperature ◽  
Combustion System ◽  
Basic Model ◽  
System A

To analysize the influence of singlet oxygen O2(a1Δg) and ozone O3on the hydrogen-air combustion system, a kinetic model must be defined. By simulating the ignition delay time, flame speed, flame temperature and the component changes of Starik model, GRI3.0 model, Konnov model and Mueller model using the software Chemkin4.1 and comparing the results with the experimental data, the Starik model is chosen as the basis of the study. Then singlet oxygen O2(a1Δg) and ozone O3is added in the basic model to form a new mechanism. The presence of singlet oxygen O2(a1Δg) and ozone O3is demonstrated to result in noticeable enhancement on flame propagation.

Experimental Study to Enhance Resistance for Boundary Layer Flashback in Swirl Burners Using Microsurfaces

2017 ◽  
Author(s):  
Mohammed Al-Fahham ◽  
Fares Amer Hatem ◽  
Ali Safa Alsaegh ◽  
Agustin Valera Medina ◽  
Samuel Bigot ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Vortex Breakdown ◽  
Combustion Stability ◽  
Combustion System ◽  
Operation Conditions ◽  
System A ◽  
Swirl Combustion ◽  
Wide Range ◽  
A New Technique ◽  
Flame Flashback

Flame flashback has been one of the major instability problems in premixed gas turbine combustion with the potential to cause considerable damage to the combustion system hardware in addition to significant increase in pollutant levels. Swirl combustion has been proven as an effective flame stabilizer over a wide range of operation conditions, although swirling systems can be prone to various types of flashback under fuel premixed conditions. Unfortunately, using methodologies for the mitigation of one flashback mechanism will lead to another one in these systems. Therefore, this paper focuses on improving Boundary Layer Flashback (BLF) while trying to mitigate Combustion Induced Vortex Breakdown (CIVB) in a medium swirl combustion system. A new technique inspired by Biomimetic Engineering has been developed to use micro-surfaces for this aim. The use of these biologically designed shapes for successful flow stabilisation allows improved control of the boundary layer, thus reducing outflow drag while resisting the random propagation of flashback. Therefore, boundary layer flashback resistance using this concept was investigated numerically and experimentally in a 150 kW tangential swirl burner to determine the effects of using a micro-surface in swirling flows with and without central air injection. Various techniques were used, including Hot Wire Anemometry, LDA measurements, LES CFD, and RANS CFD. The results showed enhancement of the system resistance to boundary layer flashback, and a new combustion stability map was generated with a wider operational region when using central injection combined with micro-surfaces, thus avoiding two types of flashback mechanisms, i.e. BLF and CIVB.

scholarly journals Multi scale numerical approach for micro-cracked viscoelastic masonry

2018 ◽  
Vol 251 ◽  
pp. 04031
Author(s):  
T.T.Nga Nguyen ◽  
S.Tuan Nguyen ◽  
N.Quang Vu ◽  
T.Ta. Nguyen ◽  
N.Hung Tran ◽  
...  
Keyword(s):  
Analytical Solution ◽  
Numerical Method ◽  
Viscoelastic Properties ◽  
Numerical Approach ◽  
Two Dimensional ◽  
Periodic Homogenization ◽  
Periodic Cell ◽  
Multi Scale ◽  
Homogenization Approach ◽  
Incremental Formulation

A multi-scale numerical method for viscoelastic micro-cracked masonry is proposed. Firstly, the effective viscoelastic properties of the masonry are modelled by a periodic homogenization approach. The Modified Maxwell (MM) model is chosen for the creep. Secondly, an incremental procedure is proposed. Thirdly, an incremental formulation is used to get the overall viscoelastic behaviour of the two dimensional periodic cell. Finally, the result of the method is validated against analytical solution.

Sign in / Sign up

Export Citation Format

Share Document