Catalytic combustion is a promising technique for producing thermal energy in MEMS(Micro Electro-Mechanical Systems) scale electrical power generators. To examine the feasibility and possible benefits of catalytic combustion in MEMS-scale channels, catalytic reactions in small diameter (1 mm) flow reactor tubes at low Reynolds numbers are simulated by using the commercial fluid dynamics code FL...

-The performance of catalysts in different forms was investigated for the design of a catalytic combustor with hydrogen fuel. The catalysts tested had dimensions of 150 x 150 mm, and consisted of a ceramic honeycomb impregnated with Pt, two Ni metal foams coated with Pd powder which differed from each other in pore size, and a ceramic foam coated with Co-Mn-Ag oxide powder. In the diffusive mod...

Homogeneous Charge Compression Ignition (HCCI) combustion is a pioneer method of combustion in which pre-mixed fuel and oxidizer (typically air) are compressed to the point of auto-ignition. HCCI engines can operate with most alternative fuels, especially, dimethyl ether (DME) which has been tested as a possible diesel fuel due to its simultaneously low NOx and PM emissions. In this paper a ...

The influence of a turbulent spectrum of the temperature field on compression ignition at constant volume under homogeneous charge compression ignition engine conditions is studied by direct numerical simulation with complex chemistry. In particular the dependence of overall ignition progress on initial mixture conditions and turbulence parameters is determined. The propagation speed of ignitio...

Homogenous charge compression ignition (HCCI) combustion is spontaneous multi-site combustion of a nominally premixed air/fuel mixture that exhibits high rate of pressure rise and short combustion duration. To avoid excessive pressure rise rate and knocking, HCCI engines are fueled with highly diluted mixture using a combination of excess air and/or EGR. HCCI combustion is attractive due to ...

oxides of nitrogen are the major emission from a diesel engine. it is due to heterogeneous diffusion combustion system with fuel-rich regions, which produce high local temperature around the periphery of the spray where high formation rate of no is promoted. various techniques are therefore employed to reduce the nox emission like egr, scr, etc. in this present work a rotating injector is a tec...

New combustion concepts developed in internal combustion engines such as homogeneous charge compression ignition (HCCI) have attracted serious attention due to the possibilities to simultaneously achieve higher efficiency and lower emissions, which will impact the environment positively. The HCCI combustion concept has potential of ultra-low NOX and particulate matter (PM) emission in compariso...

Experiments were conducted to determine exhaust emissions and combustion characteristics of a conventional diesel engine (CE) and high grade low heat rejection diesel engine (LHR) (with air gap insulated piston with superni (an alloy of nickel) crown, air gap insulated liner with superni insert and ceramic coated cylinder head)with different operating conditions [normal temperature and pre-heat...

The goal of this paper is to contribute to the design of high-performance mesocombustors, a field currently under rapid development, in particular for propulsion, e.g., for UAVs, and micro/meso-electrical power generators. This study is focused on a cylindrical combustor of 29 cm, fuelled by methane and air, which provides 2 kW of thermal power. The device was entirely designed and built at the...

In this paper, finite-time thermodynamic analysis of an air-standard internal-combustion Dual cycle is performed. Maximum power (MP), maximum power density (MPD), maximum efficient power (MEP) which are three alternative performance criteria are derived. The effects of the design parameters such as volume ratio and extreme temperature ratio of the cycle have been investigated under MP, MPD and ...