at the present work, the effect of cold exhaust gas recirculation (egr) on combustion and pollution of a dual fuel engine has been investigated by cfd code fire. the turbulent flow within the combustion chamber is simulated using the k-ε turbulence model, which is modified for engine flows. “wave” and “eddy break up” models are employed to predict combustion and spray process. the calculations ...

in this paper, by numerical simulation of gas flow, effects of divergence angles on the amplification factor, side force and thrust vector magnitude of a moveable nozzle with supersonic split line have been investigated. the study is conducted for constant exit to throat area ratio and the location of the split line is also constant. the finite volume method with second order upwind scheme for ...

Developing an effective turbulence model is important for engineering applications as well as for fundamental understanding of the flow physics. We present a mathematical derivation of a closure relating the Reynolds stress to the mean strain rate for incompressible flows. A systematic multiscale analysis expresses the Reynolds stress in terms of the solutions of local periodic cell problems. W...

In turbulence-theory, the equations for the dynamics of statistical quantities usually form an infinite system. The coupled momentum equations are the best known example. Such relations can also be derived for the n-point-distribution functions which describe the stochastic state of a tur­ bulent medium at every instant. This will be shown for the case of Vlasov turbulence. In order to obtatin ...

Appropriate descriptions of turbulence are important in predicting sediment transport and seabed evolution. We use here a three-dimensional model to investigate the impacts of sediment-induced stratification, erosion parameterization, and turbulence closures on sediment transport and morphological simulations. The model is implemented in the Proudman Oceanographic Laboratory Coastal Ocean Model...

To improve the accuracy of reactor design, this article uses k-ε, DES, LES, and SST four methods to compare simulation results velocity field in blade area, turbulence intensity, distribution fluid reactor, predict appropriate model calculation. Therefore, calculation process is more suitable for small reactors.