The central recirculation zone (CRZ) in a swirl stabilized gas turbine combustor has a dominant effect on the fuel air mixing process and flame stability. Most of state of the art swirlers share one disadvantage; the fixed swirl number for the same swirler configuration. Thus, in a mathematical sense, Reynolds number becomes the sole parameter for controlling the flow characteristics inside the...

An investigation into in-cylinder swirl and tumble flow characteristics with reduced maximum valve lifts (MVL) is presented. The experimental work was conducted in the modified four-valve optical spark-ignition (SI) test engine with three different MVL. Particle image velocimetry (PIV) was employed for measuring in-cylinder air motion and measurement results were analyzed for examining flow fie...

Pollutant emissions from diesel engines are significantly affected by fuel injection strategies that could reduce NOx and Soot emissions. For the first time and in this study, numerical simulations were performed to consider the influences of changing the injection duration in each pulse of the double injection strategies on in-cylinder parameters and pollutant emissions. Results confirmed that...

Structured catalysts for the simultaneous removal of soot and nitrogen oxides were prepared by means of coating cordierite monoliths with alumina-based suspensions containing Cu, Co or Fe and Cs as the catalytically active phase. Textural and chemical properties of the coated monoliths were determined by means of N2-physisorption, SEM and temperature programmed reduction. Their activity in the ...

On the basis of the stochastic reactor model Partially Stirred Plug Flow Reactor (PaSPFR) a model is developed that accounts for soot and NOx formation in the distributed combustion regime. This is done by means of the joint composition probability density function (PDF). The composition vector consists of the species mass fraction in the gas phase, enthalpy, and four moments of the soot partic...

This paper describes and analyzes a series of nearly CFD test cases performed as a contribu tion to the second Drag Prediction Workshop held in association with the AIAA in June Two con gurations are included DLR F wing body and wing body nacelle pylon The ability of CFD to pre dict the drag lift and pitching moment from exper iment including the delta arising from the ad dition of the nacelle ...

This paper presents a complete numerical procedure to study the fluid-structure interaction problem of incompressible flow through reed valves, typically employed in hermetic reciprocating compressors. A partitioned semi-implicit coupling scheme is implemented, which only strongly couples the added-mass-effect (pressure term) of the fluid to the structure hence, assuring numerical stability and...

This paper reports a study on the effect of helical, spiral, and helical-spiral combination manifold configuration on air motion and turbulence inside the cylinder of a Direct Injection (DI) diesel engine motored at 3000 rpm. Three-dimensional model of the manifolds and the cylinder is created and meshed using the pre-processor GAMBIT. The flow characteristics of these engine manifolds are exam...

Different CFD models of reverse-flow centrifugal separators namely swirl tubes have been built in order to study and detail analysis of the phenomenon of the "end of the vortex". The present work based on previous experience and experimental activities in the field of this phenomenon. The models was built in absolutely agree with geometrical characteristics and operating conditions of experimen...

main purpose of current study is development of a new multi zone model for direct injection diesel engines. zone configuration is based on conical shape of spray. siebers’s correlation is used for spray cone angle calculation. experimental data are used for calculation of fuel inlet mass flow rate. fuel diffusion in different zones is calculated using fick’s law. a chemical kinetics mechanism c...